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ClickHouse/src/Storages/StorageReplicatedMergeTree.cpp
Nikolai Kochetov 5ee9b56040 Do not change the snapshot after at reading from MT
2023-08-22 13:50:51 +00:00

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#include <Core/Defines.h>
#include <cstddef>
#include <ranges>
#include <chrono>
#include <base/hex.h>
#include <base/interpolate.h>
#include <Common/Macros.h>
#include <Common/MemoryTracker.h>
#include <Common/ProfileEventsScope.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/ZooKeeper/KeeperException.h>
#include <Common/ZooKeeper/Types.h>
#include <Common/escapeForFileName.h>
#include <Common/formatReadable.h>
#include <Common/noexcept_scope.h>
#include <Common/thread_local_rng.h>
#include <Common/typeid_cast.h>
#include <Common/ThreadFuzzer.h>
#include <Disks/ObjectStorages/IMetadataStorage.h>
#include <base/sort.h>
#include <Storages/buildQueryTreeForShard.h>
#include <Storages/AlterCommands.h>
#include <Storages/ColumnsDescription.h>
#include <Storages/Freeze.h>
#include <Storages/MergeTree/AsyncBlockIDsCache.h>
#include <Storages/MergeTree/DataPartStorageOnDiskFull.h>
#include <Storages/MergeTree/extractZkPathFromCreateQuery.h>
#include <Storages/MergeTree/IMergeTreeDataPart.h>
#include <Storages/MergeTree/LeaderElection.h>
#include <Storages/MergeTree/MergedBlockOutputStream.h>
#include <Storages/MergeTree/MergeFromLogEntryTask.h>
#include <Storages/MergeTree/MergeList.h>
#include <Storages/MergeTree/MergeTreeBackgroundExecutor.h>
#include <Storages/MergeTree/MergeTreeDataFormatVersion.h>
#include <Storages/MergeTree/MergeTreePartInfo.h>
#include <Storages/MergeTree/MergeTreeReaderCompact.h>
#include <Storages/MergeTree/MutateFromLogEntryTask.h>
#include <Storages/MergeTree/PinnedPartUUIDs.h>
#include <Storages/MergeTree/ReplicatedMergeTreeAddress.h>
#include <Storages/MergeTree/ReplicatedMergeTreeAttachThread.h>
#include <Storages/MergeTree/ReplicatedMergeTreeMutationEntry.h>
#include <Storages/MergeTree/ReplicatedMergeTreePartHeader.h>
#include <Storages/MergeTree/ReplicatedMergeTreeQuorumAddedParts.h>
#include <Storages/MergeTree/ReplicatedMergeTreeQuorumEntry.h>
#include <Storages/MergeTree/ReplicatedMergeTreeSink.h>
#include <Storages/MergeTree/ReplicatedMergeTreeTableMetadata.h>
#include <Storages/MergeTree/ZeroCopyLock.h>
#include <Storages/PartitionCommands.h>
#include <Storages/StorageReplicatedMergeTree.h>
#include <Storages/VirtualColumnUtils.h>
#include <Databases/DatabaseOnDisk.h>
#include <Databases/DatabaseReplicated.h>
#include <Parsers/formatAST.h>
#include <Parsers/parseQuery.h>
#include <Parsers/ASTInsertQuery.h>
#include <Parsers/ASTDropQuery.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTOptimizeQuery.h>
#include <Parsers/ASTPartition.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/queryToString.h>
#include <Parsers/ASTCheckQuery.h>
#include <Parsers/ExpressionListParsers.h>
#include <Processors/QueryPlan/QueryPlan.h>
#include <Processors/Sources/RemoteSource.h>
#include <Processors/QueryPlan/BuildQueryPipelineSettings.h>
#include <Processors/QueryPlan/Optimizations/QueryPlanOptimizationSettings.h>
#include <Processors/QueryPlan/ReadFromPreparedSource.h>
#include <Processors/Sinks/EmptySink.h>
#include <Planner/Utils.h>
#include <IO/ReadBufferFromString.h>
#include <IO/Operators.h>
#include <IO/ConnectionTimeouts.h>
#include <Interpreters/ClusterProxy/SelectStreamFactory.h>
#include <Interpreters/ClusterProxy/executeQuery.h>
#include <Interpreters/Context.h>
#include <Interpreters/DDLTask.h>
#include <Interpreters/InterpreterAlterQuery.h>
#include <Interpreters/InterpreterSelectQuery.h>
#include <Interpreters/InterpreterSelectQueryAnalyzer.h>
#include <Interpreters/InterserverCredentials.h>
#include <Interpreters/JoinedTables.h>
#include <Interpreters/PartLog.h>
#include <Interpreters/SelectQueryOptions.h>
#include <Backups/BackupEntriesCollector.h>
#include <Backups/IBackup.h>
#include <Backups/IBackupCoordination.h>
#include <Backups/IBackupEntry.h>
#include <Backups/IRestoreCoordination.h>
#include <Backups/RestorerFromBackup.h>
#include <Poco/DirectoryIterator.h>
#include <base/scope_guard.h>
#include <Common/scope_guard_safe.h>
#include <boost/algorithm/string/join.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string.hpp>
#include <algorithm>
#include <ctime>
#include <filesystem>
#include <iterator>
#include <numeric>
#include <thread>
#include <future>
namespace fs = std::filesystem;
namespace ProfileEvents
{
extern const Event ReplicatedPartFailedFetches;
extern const Event ReplicatedPartFetchesOfMerged;
extern const Event ObsoleteReplicatedParts;
extern const Event ReplicatedPartFetches;
extern const Event CreatedLogEntryForMerge;
extern const Event NotCreatedLogEntryForMerge;
extern const Event CreatedLogEntryForMutation;
extern const Event NotCreatedLogEntryForMutation;
extern const Event ReplicaPartialShutdown;
}
namespace CurrentMetrics
{
extern const Metric BackgroundFetchesPoolTask;
extern const Metric ReadonlyReplica;
}
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_READ_ALL_DATA;
extern const int NOT_IMPLEMENTED;
extern const int NO_ZOOKEEPER;
extern const int INCORRECT_DATA;
extern const int INCOMPATIBLE_COLUMNS;
extern const int REPLICA_ALREADY_EXISTS;
extern const int NO_REPLICA_HAS_PART;
extern const int LOGICAL_ERROR;
extern const int TOO_MANY_UNEXPECTED_DATA_PARTS;
extern const int ABORTED;
extern const int REPLICA_IS_NOT_IN_QUORUM;
extern const int TABLE_IS_READ_ONLY;
extern const int NOT_FOUND_NODE;
extern const int BAD_DATA_PART_NAME;
extern const int NO_ACTIVE_REPLICAS;
extern const int NOT_A_LEADER;
extern const int TABLE_WAS_NOT_DROPPED;
extern const int PARTITION_ALREADY_EXISTS;
extern const int TOO_MANY_RETRIES_TO_FETCH_PARTS;
extern const int RECEIVED_ERROR_FROM_REMOTE_IO_SERVER;
extern const int PARTITION_DOESNT_EXIST;
extern const int UNFINISHED;
extern const int RECEIVED_ERROR_TOO_MANY_REQUESTS;
extern const int PART_IS_TEMPORARILY_LOCKED;
extern const int CANNOT_ASSIGN_OPTIMIZE;
extern const int ALL_REPLICAS_LOST;
extern const int REPLICA_STATUS_CHANGED;
extern const int CANNOT_ASSIGN_ALTER;
extern const int DIRECTORY_ALREADY_EXISTS;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int UNKNOWN_POLICY;
extern const int NO_SUCH_DATA_PART;
extern const int INTERSERVER_SCHEME_DOESNT_MATCH;
extern const int DUPLICATE_DATA_PART;
extern const int BAD_ARGUMENTS;
extern const int CONCURRENT_ACCESS_NOT_SUPPORTED;
extern const int CHECKSUM_DOESNT_MATCH;
extern const int NOT_INITIALIZED;
extern const int TOO_LARGE_DISTRIBUTED_DEPTH;
extern const int TABLE_IS_DROPPED;
}
namespace ActionLocks
{
extern const StorageActionBlockType PartsMerge;
extern const StorageActionBlockType PartsFetch;
extern const StorageActionBlockType PartsSend;
extern const StorageActionBlockType ReplicationQueue;
extern const StorageActionBlockType PartsTTLMerge;
extern const StorageActionBlockType PartsMove;
extern const StorageActionBlockType PullReplicationLog;
}
static const auto QUEUE_UPDATE_ERROR_SLEEP_MS = 1 * 1000;
static const auto MUTATIONS_FINALIZING_SLEEP_MS = 1 * 1000;
static const auto MUTATIONS_FINALIZING_IDLE_SLEEP_MS = 5 * 1000;
const String StorageReplicatedMergeTree::default_zookeeper_name = "default";
void StorageReplicatedMergeTree::setZooKeeper()
{
/// Every ReplicatedMergeTree table is using only one ZooKeeper session.
/// But if several ReplicatedMergeTree tables are using different
/// ZooKeeper sessions, some queries like ATTACH PARTITION FROM may have
/// strange effects. So we always use only one session for all tables.
/// (excluding auxiliary zookeepers)
std::lock_guard lock(current_zookeeper_mutex);
if (zookeeper_name == default_zookeeper_name)
{
current_zookeeper = getContext()->getZooKeeper();
}
else
{
current_zookeeper = getContext()->getAuxiliaryZooKeeper(zookeeper_name);
}
}
zkutil::ZooKeeperPtr StorageReplicatedMergeTree::tryGetZooKeeper() const
{
std::lock_guard lock(current_zookeeper_mutex);
return current_zookeeper;
}
zkutil::ZooKeeperPtr StorageReplicatedMergeTree::getZooKeeper() const
{
auto res = tryGetZooKeeper();
if (!res)
throw Exception(ErrorCodes::NO_ZOOKEEPER, "Cannot get ZooKeeper");
return res;
}
zkutil::ZooKeeperPtr StorageReplicatedMergeTree::getZooKeeperAndAssertNotReadonly() const
{
/// There's a short period of time after connection loss when new session is created,
/// but replication queue is not reinitialized. We must ensure that table is not readonly anymore
/// before using new ZooKeeper session to write something (except maybe GET_PART) into replication log.
auto res = getZooKeeper();
assertNotReadonly();
return res;
}
String StorageReplicatedMergeTree::getEndpointName() const
{
const MergeTreeSettings & settings = getContext()->getReplicatedMergeTreeSettings();
if (settings.enable_the_endpoint_id_with_zookeeper_name_prefix)
return zookeeper_name + ":" + replica_path;
return replica_path;
}
static ConnectionTimeouts getHTTPTimeouts(ContextPtr context)
{
return ConnectionTimeouts::getHTTPTimeouts(context->getSettingsRef(), {context->getConfigRef().getUInt("keep_alive_timeout", DEFAULT_HTTP_KEEP_ALIVE_TIMEOUT), 0});
}
static MergeTreePartInfo makeDummyDropRangeForMovePartitionOrAttachPartitionFrom(const String & partition_id)
{
/// NOTE We don't have special log entry type for MOVE PARTITION/ATTACH PARTITION FROM,
/// so we use REPLACE_RANGE with dummy range of one block, which means "attach, not replace".
/// It's safe to fill drop range for MOVE PARTITION/ATTACH PARTITION FROM with zeros,
/// because drop range for REPLACE PARTITION must contain at least 2 blocks,
/// so we can distinguish dummy drop range from any real or virtual part.
/// But we should never construct such part name, even for virtual part,
/// because it can be confused with real part <partition>_0_0_0.
/// TODO get rid of this.
MergeTreePartInfo drop_range;
drop_range.partition_id = partition_id;
drop_range.min_block = 0;
drop_range.max_block = 0;
drop_range.level = 0;
drop_range.mutation = 0;
return drop_range;
}
StorageReplicatedMergeTree::StorageReplicatedMergeTree(
const String & zookeeper_path_,
const String & replica_name_,
bool attach,
const StorageID & table_id_,
const String & relative_data_path_,
const StorageInMemoryMetadata & metadata_,
ContextMutablePtr context_,
const String & date_column_name,
const MergingParams & merging_params_,
std::unique_ptr<MergeTreeSettings> settings_,
bool has_force_restore_data_flag,
RenamingRestrictions renaming_restrictions_,
bool need_check_structure)
: MergeTreeData(table_id_,
metadata_,
context_,
date_column_name,
merging_params_,
std::move(settings_),
true, /// require_part_metadata
attach,
[this] (const std::string & name) { enqueuePartForCheck(name); })
, zookeeper_name(zkutil::extractZooKeeperName(zookeeper_path_))
, zookeeper_path(zkutil::extractZooKeeperPath(zookeeper_path_, /* check_starts_with_slash */ !attach, log))
, replica_name(replica_name_)
, replica_path(fs::path(zookeeper_path) / "replicas" / replica_name_)
, reader(*this)
, writer(*this)
, merger_mutator(*this)
, merge_strategy_picker(*this)
, queue(*this, merge_strategy_picker)
, fetcher(*this)
, cleanup_thread(*this)
, async_block_ids_cache(*this)
, part_check_thread(*this)
, restarting_thread(*this)
, part_moves_between_shards_orchestrator(*this)
, renaming_restrictions(renaming_restrictions_)
, replicated_fetches_throttler(std::make_shared<Throttler>(getSettings()->max_replicated_fetches_network_bandwidth, getContext()->getReplicatedFetchesThrottler()))
, replicated_sends_throttler(std::make_shared<Throttler>(getSettings()->max_replicated_sends_network_bandwidth, getContext()->getReplicatedSendsThrottler()))
{
initializeDirectoriesAndFormatVersion(relative_data_path_, attach, date_column_name);
/// We create and deactivate all tasks for consistency.
/// They all will be scheduled and activated by the restarting thread.
queue_updating_task = getContext()->getSchedulePool().createTask(
getStorageID().getFullTableName() + " (StorageReplicatedMergeTree::queueUpdatingTask)", [this]{ queueUpdatingTask(); });
queue_updating_task->deactivate();
mutations_updating_task = getContext()->getSchedulePool().createTask(
getStorageID().getFullTableName() + " (StorageReplicatedMergeTree::mutationsUpdatingTask)", [this]{ mutationsUpdatingTask(); });
mutations_updating_task->deactivate();
mutations_watch_callback = std::make_shared<Coordination::WatchCallback>(mutations_updating_task->getWatchCallback());
merge_selecting_task = getContext()->getSchedulePool().createTask(
getStorageID().getFullTableName() + " (StorageReplicatedMergeTree::mergeSelectingTask)", [this] { mergeSelectingTask(); });
/// Will be activated if we will achieve leader state.
merge_selecting_task->deactivate();
merge_selecting_sleep_ms = getSettings()->merge_selecting_sleep_ms;
mutations_finalizing_task = getContext()->getSchedulePool().createTask(
getStorageID().getFullTableName() + " (StorageReplicatedMergeTree::mutationsFinalizingTask)", [this] { mutationsFinalizingTask(); });
/// This task can be scheduled by different parts of code even when storage is readonly.
/// This can lead to redundant exceptions during startup.
/// Will be activated by restarting thread.
mutations_finalizing_task->deactivate();
bool has_zookeeper = getContext()->hasZooKeeper() || getContext()->hasAuxiliaryZooKeeper(zookeeper_name);
if (has_zookeeper)
{
/// It's possible for getZooKeeper() to timeout if zookeeper host(s) can't
/// be reached. In such cases Poco::Exception is thrown after a connection
/// timeout - refer to src/Common/ZooKeeper/ZooKeeperImpl.cpp:866 for more info.
///
/// Side effect of this is that the CreateQuery gets interrupted and it exits.
/// But the data Directories for the tables being created aren't cleaned up.
/// This unclean state will hinder table creation on any retries and will
/// complain that the Directory for table already exists.
///
/// To achieve a clean state on failed table creations, catch this error and
/// call dropIfEmpty() method only if the operation isn't ATTACH then proceed
/// throwing the exception. Without this, the Directory for the tables need
/// to be manually deleted before retrying the CreateQuery.
try
{
if (zookeeper_name == default_zookeeper_name)
{
current_zookeeper = getContext()->getZooKeeper();
}
else
{
current_zookeeper = getContext()->getAuxiliaryZooKeeper(zookeeper_name);
}
}
catch (...)
{
if (!attach)
{
dropIfEmpty();
throw;
}
else
{
current_zookeeper = nullptr;
}
}
}
bool skip_sanity_checks = false;
/// It does not make sense for CREATE query
if (attach)
{
try
{
if (current_zookeeper && current_zookeeper->exists(replica_path + "/host"))
{
/// Check it earlier if we can (we don't want incompatible version to start).
/// If "/host" doesn't exist, then replica is probably dropped and there's nothing to check.
ReplicatedMergeTreeAttachThread::checkHasReplicaMetadataInZooKeeper(current_zookeeper, replica_path);
}
if (current_zookeeper && current_zookeeper->exists(replica_path + "/flags/force_restore_data"))
{
skip_sanity_checks = true;
current_zookeeper->remove(replica_path + "/flags/force_restore_data");
LOG_WARNING(
log,
"Skipping the limits on severity of changes to data parts and columns (flag {}/flags/force_restore_data).",
replica_path);
}
else if (has_force_restore_data_flag)
{
skip_sanity_checks = true;
LOG_WARNING(log, "Skipping the limits on severity of changes to data parts and columns (flag force_restore_data).");
}
}
catch (const Coordination::Exception & e)
{
if (!Coordination::isHardwareError(e.code))
throw;
LOG_ERROR(log, "Caught exception while checking table metadata in ZooKeeper, will recheck later: {}", e.displayText());
}
}
loadDataParts(skip_sanity_checks);
if (attach)
{
/// Provide better initial value of merge_selecting_sleep_ms on server startup
auto settings = getSettings();
size_t max_parts_in_partition = getMaxPartsCountAndSizeForPartition().first;
if (settings->parts_to_delay_insert && max_parts_in_partition < settings->parts_to_delay_insert)
{
Float64 ratio = 1.0 - static_cast<Float64>(max_parts_in_partition) / settings->parts_to_delay_insert;
merge_selecting_sleep_ms = static_cast<UInt64>(interpolateLinear(settings->merge_selecting_sleep_ms,
settings->max_merge_selecting_sleep_ms, ratio));
}
}
if (!current_zookeeper)
{
if (!attach)
{
dropIfEmpty();
throw Exception(ErrorCodes::NO_ZOOKEEPER, "Can't create replicated table without ZooKeeper");
}
has_metadata_in_zookeeper = std::nullopt;
if (!has_zookeeper)
{
/// Do not activate the replica. It will be readonly.
LOG_ERROR(log, "No ZooKeeper defined: table will stay in readonly mode.");
return;
}
}
if (attach)
{
LOG_INFO(log, "Table will be in readonly mode until initialization is finished");
attach_thread.emplace(*this);
attach_thread->setSkipSanityChecks(skip_sanity_checks);
return;
}
auto metadata_snapshot = getInMemoryMetadataPtr();
has_metadata_in_zookeeper = true;
if (!getDataPartsForInternalUsage().empty())
throw Exception(ErrorCodes::INCORRECT_DATA,
"Data directory for table already contains data parts - probably it was unclean DROP table "
"or manual intervention. You must either clear directory by hand "
"or use ATTACH TABLE instead of CREATE TABLE if you need to use that parts.");
try
{
bool is_first_replica = createTableIfNotExists(metadata_snapshot);
try
{
/// NOTE If it's the first replica, these requests to ZooKeeper look redundant, we already know everything.
/// We have to check granularity on other replicas. If it's fixed we
/// must create our new replica with fixed granularity and store this
/// information in /replica/metadata.
other_replicas_fixed_granularity = checkFixedGranularityInZookeeper();
/// Allow structure mismatch for secondary queries from Replicated database.
/// It may happen if the table was altered just after creation.
/// Metadata will be updated in cloneMetadataIfNeeded(...), metadata_version will be 0 for a while.
bool same_structure = checkTableStructure(zookeeper_path, metadata_snapshot, need_check_structure);
if (same_structure)
{
Coordination::Stat metadata_stat;
current_zookeeper->get(zookeeper_path + "/metadata", &metadata_stat);
setInMemoryMetadata(metadata_snapshot->withMetadataVersion(metadata_stat.version));
}
}
catch (Coordination::Exception & e)
{
if (!is_first_replica && e.code == Coordination::Error::ZNONODE)
throw Exception(ErrorCodes::ALL_REPLICAS_LOST, "Table {} was suddenly removed.", zookeeper_path);
else
throw;
}
if (!is_first_replica)
createReplica(metadata_snapshot);
}
catch (...)
{
/// If replica was not created, rollback creation of data directory.
dropIfEmpty();
throw;
}
createNewZooKeeperNodes();
syncPinnedPartUUIDs();
if (!has_metadata_in_zookeeper.has_value() || *has_metadata_in_zookeeper)
createTableSharedID();
initialization_done = true;
}
String StorageReplicatedMergeTree::getDefaultZooKeeperPath(const Poco::Util::AbstractConfiguration & config)
{
return config.getString("default_replica_path", "/clickhouse/tables/{uuid}/{shard}");
}
String StorageReplicatedMergeTree::getDefaultReplicaName(const Poco::Util::AbstractConfiguration & config)
{
return config.getString("default_replica_name", "{replica}");
}
bool StorageReplicatedMergeTree::checkFixedGranularityInZookeeper()
{
auto zookeeper = getZooKeeper();
String metadata_str = zookeeper->get(zookeeper_path + "/metadata");
auto metadata_from_zk = ReplicatedMergeTreeTableMetadata::parse(metadata_str);
return metadata_from_zk.index_granularity_bytes == 0;
}
void StorageReplicatedMergeTree::waitMutationToFinishOnReplicas(
const Strings & replicas, const String & mutation_id) const
{
if (replicas.empty())
return;
/// Current replica must always be present in the list as the first element because we use local mutation status
/// to check for mutation errors. So if it is not there, just add it.
const Strings * all_required_replicas = &replicas;
Strings extended_list_of_replicas;
if (replicas.front() != replica_name)
{
extended_list_of_replicas.push_back(replica_name);
extended_list_of_replicas.insert(extended_list_of_replicas.end(), replicas.begin(), replicas.end());
all_required_replicas = &extended_list_of_replicas;
}
std::set<String> inactive_replicas;
for (const String & replica : *all_required_replicas)
{
LOG_DEBUG(log, "Waiting for {} to apply mutation {}", replica, mutation_id);
zkutil::EventPtr wait_event = std::make_shared<Poco::Event>();
while (!partial_shutdown_called)
{
/// Mutation maybe killed or whole replica was deleted.
/// Wait event will unblock at this moment.
Coordination::Stat exists_stat;
if (!getZooKeeper()->exists(fs::path(zookeeper_path) / "mutations" / mutation_id, &exists_stat, wait_event))
{
throw Exception(ErrorCodes::UNFINISHED, "Mutation {} was killed, manually removed or table was dropped", mutation_id);
}
auto zookeeper = getZooKeeper();
/// Replica could be inactive.
if (!zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active"))
{
LOG_WARNING(log, "Replica {} is not active during mutation. Mutation will be done asynchronously when replica becomes active.", replica);
inactive_replicas.emplace(replica);
break;
}
String mutation_pointer = fs::path(zookeeper_path) / "replicas" / replica / "mutation_pointer";
std::string mutation_pointer_value;
/// Replica could be removed
if (!zookeeper->tryGet(mutation_pointer, mutation_pointer_value, nullptr, wait_event))
{
LOG_WARNING(log, "Replica {} was removed", replica);
break;
}
else if (mutation_pointer_value >= mutation_id) /// Maybe we already processed more fresh mutation
break; /// (numbers like 0000000000 and 0000000001)
/// Replica can become inactive, so wait with timeout and recheck it
if (wait_event->tryWait(1000))
continue;
/// Here we check mutation for errors on local replica. If they happen on this replica
/// they will happen on each replica, so we can check only in-memory info.
auto mutation_status = queue.getIncompleteMutationsStatus(mutation_id);
/// If mutation status is empty, than local replica may just not loaded it into memory.
if (mutation_status && !mutation_status->latest_fail_reason.empty())
break;
}
/// This replica inactive, don't check anything
if (!inactive_replicas.empty() && inactive_replicas.contains(replica))
break;
/// It maybe already removed from zk, but local in-memory mutations
/// state was not updated.
if (!getZooKeeper()->exists(fs::path(zookeeper_path) / "mutations" / mutation_id))
{
throw Exception(ErrorCodes::UNFINISHED, "Mutation {} was killed, manually removed or table was dropped", mutation_id);
}
if (partial_shutdown_called)
throw Exception(ErrorCodes::UNFINISHED,
"Mutation is not finished because table shutdown was called. "
"It will be done after table restart.");
/// Replica inactive, don't check mutation status
if (!inactive_replicas.empty() && inactive_replicas.contains(replica))
continue;
/// At least we have our current mutation
std::set<String> mutation_ids;
mutation_ids.insert(mutation_id);
/// Here we check mutation for errors or kill on local replica. If they happen on this replica
/// they will happen on each replica, so we can check only in-memory info.
auto mutation_status = queue.getIncompleteMutationsStatus(mutation_id, &mutation_ids);
checkMutationStatus(mutation_status, mutation_ids);
}
if (!inactive_replicas.empty())
{
throw Exception(ErrorCodes::UNFINISHED,
"Mutation is not finished because some replicas are inactive right now: {}. Mutation will be done asynchronously",
boost::algorithm::join(inactive_replicas, ", "));
}
}
void StorageReplicatedMergeTree::createNewZooKeeperNodes()
{
auto zookeeper = getZooKeeper();
std::vector<zkutil::ZooKeeper::FutureCreate> futures;
/// These 4 nodes used to be created in createNewZookeeperNodes() and they were moved to createTable()
/// This means that if the first replica creating the table metadata has an older version of CH (22.3 or previous)
/// there will be a time between its calls to `createTable` and `createNewZookeeperNodes` where the nodes won't exists
/// and that will cause issues in newer replicas
/// See https://github.com/ClickHouse/ClickHouse/issues/38600 for example
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/quorum", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/quorum/last_part", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/quorum/failed_parts", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/mutations", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/quorum/parallel", String(), zkutil::CreateMode::Persistent));
/// Nodes for remote fs zero-copy replication
const auto settings = getSettings();
if (settings->allow_remote_fs_zero_copy_replication)
{
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/zero_copy_s3", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/zero_copy_s3/shared", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/zero_copy_hdfs", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/zero_copy_hdfs/shared", String(), zkutil::CreateMode::Persistent));
}
/// Part movement.
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/part_moves_shard", String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/pinned_part_uuids", getPinnedPartUUIDs()->toString(), zkutil::CreateMode::Persistent));
/// For ALTER PARTITION with multi-leaders
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/alter_partition_version", String(), zkutil::CreateMode::Persistent));
/// For deduplication of async inserts
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/async_blocks", String(), zkutil::CreateMode::Persistent));
/// To track "lost forever" parts count, just for `system.replicas` table
futures.push_back(zookeeper->asyncTryCreateNoThrow(zookeeper_path + "/lost_part_count", String(), zkutil::CreateMode::Persistent));
/// As for now, "/temp" node must exist, but we want to be able to remove it in future
if (zookeeper->exists(zookeeper_path + "/temp"))
{
/// For block numbers allocation (since 22.11)
futures.push_back(zookeeper->asyncTryCreateNoThrow(
zookeeper_path + "/temp/" + EphemeralLockInZooKeeper::LEGACY_LOCK_INSERT, String(), zkutil::CreateMode::Persistent));
futures.push_back(zookeeper->asyncTryCreateNoThrow(
zookeeper_path + "/temp/" + EphemeralLockInZooKeeper::LEGACY_LOCK_OTHER, String(), zkutil::CreateMode::Persistent));
}
for (auto & future : futures)
{
auto res = future.get();
if (res.error != Coordination::Error::ZOK && res.error != Coordination::Error::ZNODEEXISTS)
throw Coordination::Exception(res.error, "Failed to create new nodes at {}", zookeeper_path);
}
}
bool StorageReplicatedMergeTree::createTableIfNotExists(const StorageMetadataPtr & metadata_snapshot)
{
auto zookeeper = getZooKeeper();
zookeeper->createAncestors(zookeeper_path);
for (size_t i = 0; i < 1000; ++i)
{
/// Invariant: "replicas" does not exist if there is no table or if there are leftovers from incompletely dropped table.
if (zookeeper->exists(zookeeper_path + "/replicas"))
{
LOG_DEBUG(log, "This table {} is already created, will add new replica", zookeeper_path);
return false;
}
/// There are leftovers from incompletely dropped table.
if (zookeeper->exists(zookeeper_path + "/dropped"))
{
/// This condition may happen when the previous drop attempt was not completed
/// or when table is dropped by another replica right now.
/// This is Ok because another replica is definitely going to drop the table.
LOG_WARNING(log, "Removing leftovers from table {} (this might take several minutes)", zookeeper_path);
String drop_lock_path = zookeeper_path + "/dropped/lock";
Coordination::Error code = zookeeper->tryCreate(drop_lock_path, "", zkutil::CreateMode::Ephemeral);
if (code == Coordination::Error::ZNONODE || code == Coordination::Error::ZNODEEXISTS)
{
LOG_WARNING(log, "The leftovers from table {} were removed by another replica", zookeeper_path);
}
else if (code != Coordination::Error::ZOK)
{
throw Coordination::Exception::fromPath(code, drop_lock_path);
}
else
{
auto metadata_drop_lock = zkutil::EphemeralNodeHolder::existing(drop_lock_path, *zookeeper);
if (!removeTableNodesFromZooKeeper(zookeeper, zookeeper_path, metadata_drop_lock, log))
{
/// Someone is recursively removing table right now, we cannot create new table until old one is removed
continue;
}
}
}
LOG_DEBUG(log, "Creating table {}", zookeeper_path);
/// We write metadata of table so that the replicas can check table parameters with them.
String metadata_str = ReplicatedMergeTreeTableMetadata(*this, metadata_snapshot).toString();
Coordination::Requests ops;
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path, "", zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/metadata", metadata_str,
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/columns", metadata_snapshot->getColumns().toString(),
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/log", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/blocks", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/async_blocks", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/block_numbers", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/nonincrement_block_numbers", "",
zkutil::CreateMode::Persistent)); /// /nonincrement_block_numbers dir is unused, but is created nonetheless for backwards compatibility.
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/leader_election", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/temp", "",
zkutil::CreateMode::Persistent));
/// The following 2 nodes were added in 22.11
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/temp/" + EphemeralLockInZooKeeper::LEGACY_LOCK_INSERT, "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/temp/" + EphemeralLockInZooKeeper::LEGACY_LOCK_OTHER, "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/replicas", "last added replica: " + replica_name,
zkutil::CreateMode::Persistent));
/// The following 4 nodes were added in version 1.1.xxx, so we create them here, not in createNewZooKeeperNodes()
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/quorum", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/quorum/last_part", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/quorum/failed_parts", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/mutations", "",
zkutil::CreateMode::Persistent));
/// And create first replica atomically. See also "createReplica" method that is used to create not the first replicas.
ops.emplace_back(zkutil::makeCreateRequest(replica_path, "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/host", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/log_pointer", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/queue", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/parts", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/flags", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/is_lost", "0",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/metadata", metadata_str,
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/columns", metadata_snapshot->getColumns().toString(),
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/metadata_version", toString(metadata_snapshot->getMetadataVersion()),
zkutil::CreateMode::Persistent));
/// The following 3 nodes were added in version 1.1.xxx, so we create them here, not in createNewZooKeeperNodes()
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/min_unprocessed_insert_time", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/max_processed_insert_time", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/mutation_pointer", "",
zkutil::CreateMode::Persistent));
Coordination::Responses responses;
auto code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZNODEEXISTS)
{
LOG_INFO(log, "It looks like the table {} was created by another server at the same moment, will retry", zookeeper_path);
continue;
}
else if (code != Coordination::Error::ZOK)
{
zkutil::KeeperMultiException::check(code, ops, responses);
}
return true;
}
/// Do not use LOGICAL_ERROR code, because it may happen if user has specified wrong zookeeper_path
throw Exception(ErrorCodes::REPLICA_ALREADY_EXISTS,
"Cannot create table, because it is created concurrently every time or because "
"of wrong zookeeper_path or because of logical error");
}
void StorageReplicatedMergeTree::createReplica(const StorageMetadataPtr & metadata_snapshot)
{
auto zookeeper = getZooKeeper();
LOG_DEBUG(log, "Creating replica {}", replica_path);
Coordination::Error code;
do
{
Coordination::Stat replicas_stat;
String replicas_value;
if (!zookeeper->tryGet(zookeeper_path + "/replicas", replicas_value, &replicas_stat))
throw Exception(ErrorCodes::ALL_REPLICAS_LOST,
"Cannot create a replica of the table {}, because the last replica of the table was dropped right now",
zookeeper_path);
/// It is not the first replica, we will mark it as "lost", to immediately repair (clone) from existing replica.
/// By the way, it's possible that the replica will be first, if all previous replicas were removed concurrently.
const String is_lost_value = replicas_stat.numChildren ? "1" : "0";
Coordination::Requests ops;
ops.emplace_back(zkutil::makeCreateRequest(replica_path, "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/host", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/log_pointer", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/queue", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/parts", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/flags", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/is_lost", is_lost_value,
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/metadata", ReplicatedMergeTreeTableMetadata(*this, metadata_snapshot).toString(),
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/columns", metadata_snapshot->getColumns().toString(),
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/metadata_version", toString(metadata_snapshot->getMetadataVersion()),
zkutil::CreateMode::Persistent));
/// The following 3 nodes were added in version 1.1.xxx, so we create them here, not in createNewZooKeeperNodes()
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/min_unprocessed_insert_time", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/max_processed_insert_time", "",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(replica_path + "/mutation_pointer", "",
zkutil::CreateMode::Persistent));
/// Check version of /replicas to see if there are any replicas created at the same moment of time.
ops.emplace_back(zkutil::makeSetRequest(zookeeper_path + "/replicas", "last added replica: " + replica_name, replicas_stat.version));
Coordination::Responses responses;
code = zookeeper->tryMulti(ops, responses);
switch (code)
{
case Coordination::Error::ZNODEEXISTS:
throw Exception(ErrorCodes::REPLICA_ALREADY_EXISTS, "Replica {} already exists", replica_path);
case Coordination::Error::ZBADVERSION:
LOG_INFO(log, "Retrying createReplica(), because some other replicas were created at the same time");
break;
case Coordination::Error::ZNONODE:
throw Exception(ErrorCodes::ALL_REPLICAS_LOST, "Table {} was suddenly removed", zookeeper_path);
default:
zkutil::KeeperMultiException::check(code, ops, responses);
}
} while (code == Coordination::Error::ZBADVERSION);
}
zkutil::ZooKeeperPtr StorageReplicatedMergeTree::getZooKeeperIfTableShutDown() const
{
zkutil::ZooKeeperPtr maybe_new_zookeeper;
if (zookeeper_name == default_zookeeper_name)
maybe_new_zookeeper = getContext()->getZooKeeper();
else
maybe_new_zookeeper = getContext()->getAuxiliaryZooKeeper(zookeeper_name);
maybe_new_zookeeper->sync(zookeeper_path);
return maybe_new_zookeeper;
}
void StorageReplicatedMergeTree::drop()
{
/// There is also the case when user has configured ClickHouse to wrong ZooKeeper cluster
/// or metadata of staled replica were removed manually,
/// in this case, has_metadata_in_zookeeper = false, and we also permit to drop the table.
bool maybe_has_metadata_in_zookeeper = !has_metadata_in_zookeeper.has_value() || *has_metadata_in_zookeeper;
zkutil::ZooKeeperPtr zookeeper;
if (maybe_has_metadata_in_zookeeper)
{
/// Table can be shut down, restarting thread is not active
/// and calling StorageReplicatedMergeTree::getZooKeeper()/getAuxiliaryZooKeeper() won't suffice.
zookeeper = getZooKeeperIfTableShutDown();
/// If probably there is metadata in ZooKeeper, we don't allow to drop the table.
if (!zookeeper)
throw Exception(ErrorCodes::TABLE_IS_READ_ONLY, "Can't drop readonly replicated table (need to drop data in ZooKeeper as well)");
}
/// Wait for loading of all outdated parts because
/// in case of zero copy recursive removal of directory
/// is not supported and table cannot be dropped.
if (canUseZeroCopyReplication())
{
/// Load remaining parts synchronously because task
/// for loading is already cancelled in shutdown().
loadOutdatedDataParts(/*is_async=*/ false);
}
dropAllData();
if (maybe_has_metadata_in_zookeeper)
{
/// Session could expire, get it again
zookeeper = getZooKeeperIfTableShutDown();
dropReplica(zookeeper, zookeeper_path, replica_name, log, getSettings(), &has_metadata_in_zookeeper);
}
}
void StorageReplicatedMergeTree::dropReplica(zkutil::ZooKeeperPtr zookeeper, const String & zookeeper_path, const String & replica,
Poco::Logger * logger, MergeTreeSettingsPtr table_settings, std::optional<bool> * has_metadata_out)
{
if (zookeeper->expired())
throw Exception(ErrorCodes::TABLE_WAS_NOT_DROPPED, "Table was not dropped because ZooKeeper session has expired.");
auto remote_replica_path = zookeeper_path + "/replicas/" + replica;
LOG_INFO(logger, "Removing replica {}, marking it as lost", remote_replica_path);
/// Mark itself lost before removing, because the following recursive removal may fail
/// and partially dropped replica may be considered as alive one (until someone will mark it lost)
zookeeper->trySet(remote_replica_path + "/is_lost", "1");
/// NOTE: we should check for remote_replica_path existence,
/// since otherwise DROP REPLICA will fail if the replica had been already removed.
if (!zookeeper->exists(remote_replica_path))
{
LOG_INFO(logger, "Removing replica {} does not exist", remote_replica_path);
return;
}
{
/// Remove "host" node first to mark replica as dropped (the choice is arbitrary,
/// it could be any node without children that exists since ancient server versions and not re-created on startup)
[[maybe_unused]] auto code = zookeeper->tryRemove(fs::path(remote_replica_path) / "host");
assert(code == Coordination::Error::ZOK || code == Coordination::Error::ZNONODE);
/// Then try to remove paths that are known to be flat (all children are leafs)
Strings flat_nodes = {"flags", "queue"};
if (table_settings && table_settings->use_minimalistic_part_header_in_zookeeper)
flat_nodes.emplace_back("parts");
for (const auto & node : flat_nodes)
{
bool removed_quickly = zookeeper->tryRemoveChildrenRecursive(fs::path(remote_replica_path) / node, /* probably flat */ true);
if (!removed_quickly)
LOG_WARNING(logger, "Failed to quickly remove node '{}' and its children, fell back to recursive removal (replica: {})",
node, remote_replica_path);
}
/// Then try to remove nodes that are known to have no children (and should always exist)
Coordination::Requests ops;
for (const auto & node : flat_nodes)
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/" + node, -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/columns", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/is_lost", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/log_pointer", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/max_processed_insert_time", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/min_unprocessed_insert_time", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/metadata", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/metadata_version", -1));
ops.emplace_back(zkutil::makeRemoveRequest(remote_replica_path + "/mutation_pointer", -1));
Coordination::Responses res;
code = zookeeper->tryMulti(ops, res);
if (code != Coordination::Error::ZOK)
LOG_WARNING(logger, "Cannot quickly remove nodes without children: {} (replica: {}). Will remove recursively.",
code, remote_replica_path);
/// And finally remove everything else recursively
/// It may left some garbage if replica_path subtree is concurrently modified
zookeeper->tryRemoveChildrenRecursive(remote_replica_path);
/// Update has_metadata_in_zookeeper to avoid retries. Otherwise we can accidentally remove metadata of a new table on retries
if (has_metadata_out)
*has_metadata_out = false;
if (zookeeper->tryRemove(remote_replica_path) != Coordination::Error::ZOK)
LOG_ERROR(logger, "Replica was not completely removed from ZooKeeper, {} still exists and may contain some garbage.", remote_replica_path);
}
/// Check that `zookeeper_path` exists: it could have been deleted by another replica after execution of previous line.
Strings replicas;
if (Coordination::Error::ZOK != zookeeper->tryGetChildren(zookeeper_path + "/replicas", replicas) || !replicas.empty())
return;
LOG_INFO(logger, "{} is the last replica, will remove table", remote_replica_path);
/** At this moment, another replica can be created and we cannot remove the table.
* Try to remove /replicas node first. If we successfully removed it,
* it guarantees that we are the only replica that proceed to remove the table
* and no new replicas can be created after that moment (it requires the existence of /replicas node).
* and table cannot be recreated with new /replicas node on another servers while we are removing data,
* because table creation is executed in single transaction that will conflict with remaining nodes.
*/
/// Node /dropped works like a lock that protects from concurrent removal of old table and creation of new table.
/// But recursive removal may fail in the middle of operation leaving some garbage in zookeeper_path, so
/// we remove it on table creation if there is /dropped node. Creating thread may remove /dropped node created by
/// removing thread, and it causes race condition if removing thread is not finished yet.
/// To avoid this we also create ephemeral child before starting recursive removal.
/// (The existence of child node does not allow to remove parent node).
Coordination::Requests ops;
Coordination::Responses responses;
String drop_lock_path = zookeeper_path + "/dropped/lock";
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/replicas", -1));
ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/dropped", "", zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(drop_lock_path, "", zkutil::CreateMode::Ephemeral));
Coordination::Error code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZNONODE || code == Coordination::Error::ZNODEEXISTS)
{
LOG_WARNING(logger, "Table {} is already started to be removing by another replica right now", remote_replica_path);
}
else if (code == Coordination::Error::ZNOTEMPTY)
{
LOG_WARNING(logger, "Another replica was suddenly created, will keep the table {}", remote_replica_path);
}
else if (code != Coordination::Error::ZOK)
{
zkutil::KeeperMultiException::check(code, ops, responses);
}
else
{
auto metadata_drop_lock = zkutil::EphemeralNodeHolder::existing(drop_lock_path, *zookeeper);
LOG_INFO(logger, "Removing table {} (this might take several minutes)", zookeeper_path);
removeTableNodesFromZooKeeper(zookeeper, zookeeper_path, metadata_drop_lock, logger);
}
}
void StorageReplicatedMergeTree::dropReplica(const String & drop_zookeeper_path, const String & drop_replica, Poco::Logger * logger)
{
zkutil::ZooKeeperPtr zookeeper = getZooKeeperIfTableShutDown();
/// NOTE it's not atomic: replica may become active after this check, but before dropReplica(...)
/// However, the main use case is to drop dead replica, which cannot become active.
/// This check prevents only from accidental drop of some other replica.
if (zookeeper->exists(drop_zookeeper_path + "/replicas/" + drop_replica + "/is_active"))
throw Exception(ErrorCodes::TABLE_WAS_NOT_DROPPED, "Can't drop replica: {}, because it's active", drop_replica);
dropReplica(zookeeper, drop_zookeeper_path, drop_replica, logger);
}
bool StorageReplicatedMergeTree::removeTableNodesFromZooKeeper(zkutil::ZooKeeperPtr zookeeper,
const String & zookeeper_path, const zkutil::EphemeralNodeHolder::Ptr & metadata_drop_lock, Poco::Logger * logger)
{
bool completely_removed = false;
/// NOTE /block_numbers/ actually is not flat, because /block_numbers/<partition_id>/ may have ephemeral children,
/// but we assume that all ephemeral block locks are already removed when table is being dropped.
static constexpr std::array flat_nodes = {"block_numbers", "blocks", "async_blocks", "leader_election", "log", "mutations", "pinned_part_uuids"};
/// First try to remove paths that are known to be flat
for (const auto * node : flat_nodes)
{
bool removed_quickly = zookeeper->tryRemoveChildrenRecursive(fs::path(zookeeper_path) / node, /* probably flat */ true);
if (!removed_quickly)
LOG_WARNING(logger, "Failed to quickly remove node '{}' and its children, fell back to recursive removal (table: {})",
node, zookeeper_path);
}
/// Then try to remove nodes that are known to have no children (and should always exist)
Coordination::Requests ops;
for (const auto * node : flat_nodes)
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/" + node, -1));
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/alter_partition_version", -1));
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/columns", -1));
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/metadata", -1));
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path + "/table_shared_id", -1));
Coordination::Responses res;
auto code = zookeeper->tryMulti(ops, res);
if (code != Coordination::Error::ZOK)
LOG_WARNING(logger, "Cannot quickly remove nodes without children: {} (table: {}). Will remove recursively.",
code, zookeeper_path);
Strings children;
code = zookeeper->tryGetChildren(zookeeper_path, children);
if (code == Coordination::Error::ZNONODE)
throw Exception(ErrorCodes::LOGICAL_ERROR, "There is a race condition between creation and removal of replicated table. It's a bug");
for (const auto & child : children)
{
if (child != "dropped")
zookeeper->tryRemoveRecursive(fs::path(zookeeper_path) / child);
}
ops.clear();
Coordination::Responses responses;
ops.emplace_back(zkutil::makeRemoveRequest(metadata_drop_lock->getPath(), -1));
ops.emplace_back(zkutil::makeRemoveRequest(fs::path(zookeeper_path) / "dropped", -1));
ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path, -1));
code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZNONODE)
{
throw Exception(ErrorCodes::LOGICAL_ERROR, "There is a race condition between creation and removal of replicated table. It's a bug");
}
else if (code == Coordination::Error::ZNOTEMPTY)
{
LOG_ERROR(logger, "Table was not completely removed from ZooKeeper, {} still exists and may contain some garbage,"
"but someone is removing it right now.", zookeeper_path);
}
else if (code != Coordination::Error::ZOK)
{
/// It is still possible that ZooKeeper session is expired or server is killed in the middle of the delete operation.
zkutil::KeeperMultiException::check(code, ops, responses);
}
else
{
metadata_drop_lock->setAlreadyRemoved();
completely_removed = true;
LOG_INFO(logger, "Table {} was successfully removed from ZooKeeper", zookeeper_path);
}
return completely_removed;
}
/** Verify that list of columns and table storage_settings_ptr match those specified in ZK (/metadata).
* If not, throw an exception.
*/
bool StorageReplicatedMergeTree::checkTableStructure(const String & zookeeper_prefix, const StorageMetadataPtr & metadata_snapshot, bool strict_check)
{
auto zookeeper = getZooKeeper();
ReplicatedMergeTreeTableMetadata old_metadata(*this, metadata_snapshot);
Coordination::Stat metadata_stat;
String metadata_str = zookeeper->get(fs::path(zookeeper_prefix) / "metadata", &metadata_stat);
auto metadata_from_zk = ReplicatedMergeTreeTableMetadata::parse(metadata_str);
old_metadata.checkEquals(metadata_from_zk, metadata_snapshot->getColumns(), getContext());
Coordination::Stat columns_stat;
auto columns_from_zk = ColumnsDescription::parse(zookeeper->get(fs::path(zookeeper_prefix) / "columns", &columns_stat));
const ColumnsDescription & old_columns = metadata_snapshot->getColumns();
if (columns_from_zk == old_columns)
return true;
if (!strict_check && metadata_stat.version != 0)
{
LOG_WARNING(log, "Table columns structure in ZooKeeper is different from local table structure. "
"Assuming it's because the table was altered concurrently. Metadata version: {}. Local columns:\n"
"{}\nZookeeper columns:\n{}", metadata_stat.version, old_columns.toString(), columns_from_zk.toString());
return false;
}
throw Exception(ErrorCodes::INCOMPATIBLE_COLUMNS,
"Table columns structure in ZooKeeper is different from local table structure. Local columns:\n"
"{}\nZookeeper columns:\n{}", old_columns.toString(), columns_from_zk.toString());
}
void StorageReplicatedMergeTree::setTableStructure(const StorageID & table_id, const ContextPtr & local_context,
ColumnsDescription new_columns, const ReplicatedMergeTreeTableMetadata::Diff & metadata_diff, int32_t new_metadata_version)
{
StorageInMemoryMetadata old_metadata = getInMemoryMetadata();
StorageInMemoryMetadata new_metadata = metadata_diff.getNewMetadata(new_columns, local_context, old_metadata);
new_metadata.setMetadataVersion(new_metadata_version);
/// Even if the primary/sorting/partition keys didn't change we must reinitialize it
/// because primary/partition key column types might have changed.
checkTTLExpressions(new_metadata, old_metadata);
setProperties(new_metadata, old_metadata);
DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(local_context, table_id, new_metadata);
}
/** If necessary, restore a part, replica itself adds a record for its receipt.
* What time should I put for this entry in the queue? Time is taken into account when calculating lag of replica.
* For these purposes, it makes sense to use creation time of missing part
* (that is, in calculating lag, it will be taken into account how old is the part we need to recover).
*/
static time_t tryGetPartCreateTime(zkutil::ZooKeeperPtr & zookeeper, const String & replica_path, const String & part_name)
{
time_t res = 0;
/// We get creation time of part, if it still exists (was not merged, for example).
Coordination::Stat stat;
String unused;
if (zookeeper->tryGet(fs::path(replica_path) / "parts" / part_name, unused, &stat))
res = stat.ctime / 1000;
return res;
}
void StorageReplicatedMergeTree::paranoidCheckForCoveredPartsInZooKeeperOnStart(const Strings & parts_in_zk, const Strings & parts_to_fetch) const
{
#ifdef ABORT_ON_LOGICAL_ERROR
constexpr bool paranoid_check_for_covered_parts_default = true;
#else
constexpr bool paranoid_check_for_covered_parts_default = false;
#endif
bool paranoid_check_for_covered_parts = Context::getGlobalContextInstance()->getConfigRef().getBool(
"replicated_merge_tree_paranoid_check_on_startup", paranoid_check_for_covered_parts_default);
if (!paranoid_check_for_covered_parts)
return;
/// FIXME https://github.com/ClickHouse/ClickHouse/issues/51182
if (getSettings()->use_metadata_cache)
return;
ActiveDataPartSet active_set(format_version);
for (const auto & part_name : parts_in_zk)
active_set.add(part_name);
const auto disks = getStoragePolicy()->getDisks();
auto path = getRelativeDataPath();
for (const auto & part_name : parts_in_zk)
{
String covering_part = active_set.getContainingPart(part_name);
if (part_name == covering_part)
continue;
bool found = false;
for (const DiskPtr & disk : disks)
if (disk->exists(fs::path(path) / part_name))
found = true;
if (!found)
found = std::find(parts_to_fetch.begin(), parts_to_fetch.end(), part_name) != parts_to_fetch.end();
if (!found)
{
LOG_WARNING(log, "Part {} exists in ZooKeeper and covered by another part in ZooKeeper ({}), but doesn't exist on any disk. "
"It may cause false-positive 'part is lost forever' messages", part_name, covering_part);
chassert(false);
}
}
}
void StorageReplicatedMergeTree::checkParts(bool skip_sanity_checks)
{
auto zookeeper = getZooKeeper();
Strings expected_parts_vec = zookeeper->getChildren(fs::path(replica_path) / "parts");
/// Parts in ZK.
NameSet expected_parts(expected_parts_vec.begin(), expected_parts_vec.end());
/// There are no PreActive parts at startup.
auto parts = getDataParts({MergeTreeDataPartState::Active, MergeTreeDataPartState::Outdated});
/** Local parts that are not in ZK.
* In very rare cases they may cover missing parts
* and someone may think that pushing them to zookeeper is good idea.
* But actually we can't precisely determine that ALL missing parts
* covered by this unexpected part. So missing parts will be downloaded.
*/
DataParts unexpected_parts;
/// Intersection of local parts and expected parts
ActiveDataPartSet local_expected_parts_set(format_version);
/// Collect unexpected parts
for (const auto & part : parts)
{
if (expected_parts.contains(part->name))
local_expected_parts_set.add(part->name);
else
unexpected_parts.insert(part); /// this parts we will place to detached with ignored_ prefix
}
/// Which parts should be taken from other replicas.
Strings parts_to_fetch;
for (const String & missing_name : expected_parts)
if (!getActiveContainingPart(missing_name))
parts_to_fetch.push_back(missing_name);
paranoidCheckForCoveredPartsInZooKeeperOnStart(expected_parts_vec, parts_to_fetch);
/** To check the adequacy, for the parts that are in the FS, but not in ZK, we will only consider not the most recent parts.
* Because unexpected new parts usually arise only because they did not have time to enroll in ZK with a rough restart of the server.
* It also occurs from deduplicated parts that did not have time to retire.
*/
size_t unexpected_parts_nonnew = 0;
UInt64 unexpected_parts_nonnew_rows = 0;
UInt64 unexpected_parts_rows = 0;
Strings covered_unexpected_parts;
Strings uncovered_unexpected_parts;
UInt64 uncovered_unexpected_parts_rows = 0;
for (const auto & part : unexpected_parts)
{
unexpected_parts_rows += part->rows_count;
/// This part may be covered by some expected part that is active and present locally
/// Probably we just did not remove this part from disk before restart (but removed from ZooKeeper)
String covering_local_part = local_expected_parts_set.getContainingPart(part->name);
if (!covering_local_part.empty())
{
covered_unexpected_parts.push_back(part->name);
continue;
}
/// Part is unexpected and we don't have covering part: it's suspicious
uncovered_unexpected_parts.push_back(part->name);
uncovered_unexpected_parts_rows += part->rows_count;
if (part->info.level > 0)
{
++unexpected_parts_nonnew;
unexpected_parts_nonnew_rows += part->rows_count;
}
}
const UInt64 parts_to_fetch_blocks = std::accumulate(parts_to_fetch.cbegin(), parts_to_fetch.cend(), 0,
[&](UInt64 acc, const String & part_name)
{
if (const auto part_info = MergeTreePartInfo::tryParsePartName(part_name, format_version))
return acc + part_info->getBlocksCount();
LOG_ERROR(log, "Unexpected part name: {}", part_name);
return acc;
});
/** We can automatically synchronize data,
* if the ratio of the total number of errors to the total number of parts (minimum - on the local filesystem or in ZK)
* is no more than some threshold (for example 50%).
*
* A large ratio of mismatches in the data on the filesystem and the expected data
* may indicate a configuration error (the server accidentally connected as a replica not from right shard).
* In this case, the protection mechanism does not allow the server to start.
*/
UInt64 total_rows_on_filesystem = 0;
for (const auto & part : parts)
total_rows_on_filesystem += part->rows_count;
const auto storage_settings_ptr = getSettings();
bool insane = uncovered_unexpected_parts_rows > total_rows_on_filesystem * storage_settings_ptr->replicated_max_ratio_of_wrong_parts;
constexpr auto sanity_report_fmt = "The local set of parts of table {} doesn't look like the set of parts in ZooKeeper: "
"{} rows of {} total rows in filesystem are suspicious. "
"There are {} uncovered unexpected parts with {} rows ({} of them is not just-written with {} rows), "
"{} missing parts (with {} blocks), {} covered unexpected parts (with {} rows).";
constexpr auto sanity_report_debug_fmt = "Uncovered unexpected parts: {}. Missing parts: {}. Covered unexpected parts: {}. Expected parts: {}.";
if (insane && !skip_sanity_checks)
{
LOG_DEBUG(log, sanity_report_debug_fmt, fmt::join(uncovered_unexpected_parts, ", "), fmt::join(parts_to_fetch, ", "),
fmt::join(covered_unexpected_parts, ", "), fmt::join(expected_parts, ", "));
throw Exception(ErrorCodes::TOO_MANY_UNEXPECTED_DATA_PARTS, sanity_report_fmt, getStorageID().getNameForLogs(),
formatReadableQuantity(uncovered_unexpected_parts_rows),
formatReadableQuantity(total_rows_on_filesystem),
uncovered_unexpected_parts.size(), uncovered_unexpected_parts_rows, unexpected_parts_nonnew, unexpected_parts_nonnew_rows,
parts_to_fetch.size(), parts_to_fetch_blocks, covered_unexpected_parts.size(),
unexpected_parts_rows - uncovered_unexpected_parts_rows);
}
if (unexpected_parts_nonnew_rows > 0 || uncovered_unexpected_parts_rows > 0)
{
LOG_DEBUG(log, sanity_report_debug_fmt, fmt::join(uncovered_unexpected_parts, ", "), fmt::join(parts_to_fetch, ", "),
fmt::join(covered_unexpected_parts, ", "), fmt::join(expected_parts, ", "));
LOG_WARNING(log, sanity_report_fmt, getStorageID().getNameForLogs(),
formatReadableQuantity(uncovered_unexpected_parts_rows), formatReadableQuantity(total_rows_on_filesystem),
uncovered_unexpected_parts.size(), uncovered_unexpected_parts_rows, unexpected_parts_nonnew, unexpected_parts_nonnew_rows,
parts_to_fetch.size(), parts_to_fetch_blocks, covered_unexpected_parts.size(), unexpected_parts_rows - uncovered_unexpected_parts_rows);
}
else
{
if (!parts_to_fetch.empty())
LOG_DEBUG(log, "Found parts to fetch (exist in zookeeper, but not locally): [{}]", fmt::join(parts_to_fetch, ", "));
}
/// Add to the queue jobs to pick up the missing parts from other replicas and remove from ZK the information that we have them.
queue.setBrokenPartsToEnqueueFetchesOnLoading(std::move(parts_to_fetch));
/// Remove extra local parts.
for (const DataPartPtr & part : unexpected_parts)
{
LOG_ERROR(log, "Renaming unexpected part {} to ignored_{}", part->name, part->name);
forcefullyMovePartToDetachedAndRemoveFromMemory(part, "ignored", true);
}
}
void StorageReplicatedMergeTree::syncPinnedPartUUIDs()
{
auto zookeeper = getZooKeeper();
Coordination::Stat stat;
String s = zookeeper->get(zookeeper_path + "/pinned_part_uuids", &stat);
std::lock_guard lock(pinned_part_uuids_mutex);
/// Unsure whether or not this can be called concurrently.
if (pinned_part_uuids->stat.version < stat.version)
{
auto new_pinned_part_uuids = std::make_shared<PinnedPartUUIDs>();
new_pinned_part_uuids->fromString(s);
new_pinned_part_uuids->stat = stat;
pinned_part_uuids = new_pinned_part_uuids;
}
}
void StorageReplicatedMergeTree::checkPartChecksumsAndAddCommitOps(const zkutil::ZooKeeperPtr & zookeeper,
const DataPartPtr & part, Coordination::Requests & ops, String part_name, NameSet * absent_replicas_paths)
{
if (part_name.empty())
part_name = part->name;
auto local_part_header = ReplicatedMergeTreePartHeader::fromColumnsAndChecksums(
part->getColumns(), part->checksums);
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
bool has_been_already_added = false;
for (const String & replica : replicas)
{
String current_part_path = fs::path(zookeeper_path) / "replicas" / replica / "parts" / part_name;
String part_zk_str;
if (!zookeeper->tryGet(current_part_path, part_zk_str))
{
if (absent_replicas_paths)
absent_replicas_paths->emplace(current_part_path);
continue;
}
ReplicatedMergeTreePartHeader replica_part_header;
if (part_zk_str.empty())
{
String columns_str;
String checksums_str;
if (zookeeper->tryGet(fs::path(current_part_path) / "columns", columns_str) &&
zookeeper->tryGet(fs::path(current_part_path) / "checksums", checksums_str))
{
replica_part_header = ReplicatedMergeTreePartHeader::fromColumnsAndChecksumsZNodes(columns_str, checksums_str);
}
else
{
if (zookeeper->exists(current_part_path))
throw Exception(ErrorCodes::LOGICAL_ERROR, "Part {} has empty header and does not have columns and checksums. "
"Looks like a bug.", current_part_path);
LOG_INFO(log, "Not checking checksums of part {} with replica {} because part was removed from ZooKeeper", part_name, replica);
continue;
}
}
else
{
replica_part_header = ReplicatedMergeTreePartHeader::fromString(part_zk_str);
}
if (replica_part_header.getColumnsHash() != local_part_header.getColumnsHash())
{
/// Currently there are two (known) cases when it may happen:
/// - KILL MUTATION query had removed mutation before all replicas have executed assigned MUTATE_PART entries.
/// Some replicas may skip this mutation and update part version without actually applying any changes.
/// It leads to mismatching checksum if changes were applied on other replicas.
/// - ALTER_METADATA and MERGE_PARTS were reordered on some replicas.
/// It may lead to different number of columns in merged parts on these replicas.
throw Exception(ErrorCodes::CHECKSUM_DOESNT_MATCH, "Part {} from {} has different columns hash "
"(it may rarely happen on race condition with KILL MUTATION or ALTER COLUMN).", part_name, replica);
}
replica_part_header.getChecksums().checkEqual(local_part_header.getChecksums(), true);
if (replica == replica_name)
has_been_already_added = true;
/// If we verify checksums in "sequential manner" (i.e. recheck absence of checksums on other replicas when commit)
/// then it is enough to verify checksums on at least one replica since checksums on other replicas must be the same.
if (absent_replicas_paths)
{
absent_replicas_paths->clear();
break;
}
}
if (!has_been_already_added)
{
const auto storage_settings_ptr = getSettings();
String part_path = fs::path(replica_path) / "parts" / part_name;
if (storage_settings_ptr->use_minimalistic_part_header_in_zookeeper)
{
ops.emplace_back(zkutil::makeCreateRequest(
part_path, local_part_header.toString(), zkutil::CreateMode::Persistent));
}
else
{
ops.emplace_back(zkutil::makeCreateRequest(
part_path, "", zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(part_path) / "columns", part->getColumns().toString(), zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(part_path) / "checksums", getChecksumsForZooKeeper(part->checksums), zkutil::CreateMode::Persistent));
}
}
else
{
LOG_WARNING(log, "checkPartAndAddToZooKeeper: node {} already exists. Will not commit any nodes.",
(fs::path(replica_path) / "parts" / part_name).string());
}
}
MergeTreeData::DataPartsVector StorageReplicatedMergeTree::checkPartChecksumsAndCommit(Transaction & transaction,
const MutableDataPartPtr & part, std::optional<HardlinkedFiles> hardlinked_files, bool replace_zero_copy_lock)
{
auto zookeeper = getZooKeeper();
while (true)
{
LOG_DEBUG(log, "Committing part {} to zookeeper", part->name);
Coordination::Requests ops;
NameSet absent_part_paths_on_replicas;
getLockSharedDataOps(*part, std::make_shared<ZooKeeperWithFaultInjection>(zookeeper), replace_zero_copy_lock, hardlinked_files, ops);
size_t zero_copy_lock_ops_size = ops.size();
/// Checksums are checked here and `ops` is filled. In fact, the part is added to ZK just below, when executing `multi`.
checkPartChecksumsAndAddCommitOps(zookeeper, part, ops, part->name, &absent_part_paths_on_replicas);
/// Do not commit if the part is obsolete, we have just briefly checked its checksums
if (transaction.isEmpty())
return {};
/// Will check that the part did not suddenly appear on skipped replicas
if (!absent_part_paths_on_replicas.empty())
{
Coordination::Requests new_ops;
for (const String & part_path : absent_part_paths_on_replicas)
{
/// NOTE Create request may fail with ZNONODE if replica is being dropped, we will throw an exception
new_ops.emplace_back(zkutil::makeCreateRequest(part_path, "", zkutil::CreateMode::Persistent));
new_ops.emplace_back(zkutil::makeRemoveRequest(part_path, -1));
}
/// Add check ops at the beginning
new_ops.insert(new_ops.end(), ops.begin(), ops.end());
ops = std::move(new_ops);
}
Coordination::Responses responses;
Coordination::Error e = zookeeper->tryMulti(ops, responses);
if (e == Coordination::Error::ZOK)
{
LOG_DEBUG(log, "Part {} committed to zookeeper", part->name);
return transaction.commit();
}
if (e == Coordination::Error::ZNODEEXISTS)
{
size_t num_check_ops = 2 * absent_part_paths_on_replicas.size() + zero_copy_lock_ops_size;
size_t failed_op_index = zkutil::getFailedOpIndex(e, responses);
if (failed_op_index < num_check_ops)
{
LOG_INFO(log, "The part {} on a replica suddenly appeared, will recheck checksums", ops[failed_op_index]->getPath());
continue;
}
}
throw zkutil::KeeperException(e);
}
}
String StorageReplicatedMergeTree::getChecksumsForZooKeeper(const MergeTreeDataPartChecksums & checksums) const
{
return MinimalisticDataPartChecksums::getSerializedString(checksums,
getSettings()->use_minimalistic_checksums_in_zookeeper);
}
MergeTreeData::MutableDataPartPtr StorageReplicatedMergeTree::attachPartHelperFoundValidPart(const LogEntry & entry) const
{
if (format_version != MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
return {};
const MergeTreePartInfo actual_part_info = MergeTreePartInfo::fromPartName(entry.new_part_name, format_version);
const String part_new_name = actual_part_info.getPartNameV1();
for (const DiskPtr & disk : getStoragePolicy()->getDisks())
{
for (const auto it = disk->iterateDirectory(fs::path(relative_data_path) / "detached/"); it->isValid(); it->next())
{
const auto part_info = MergeTreePartInfo::tryParsePartName(it->name(), format_version);
if (!part_info || part_info->partition_id != actual_part_info.partition_id)
continue;
const auto part_old_name = part_info->getPartNameV1();
const auto volume = std::make_shared<SingleDiskVolume>("volume_" + part_old_name, disk);
auto part = getDataPartBuilder(entry.new_part_name, volume, fs::path("detached") / part_old_name)
.withPartFormatFromDisk()
.build();
try
{
part->loadColumnsChecksumsIndexes(true, true);
}
catch (const Exception&)
{
/// This method throws if the part data is corrupted or partly missing. In this case, we simply don't
/// process the part.
continue;
}
if (entry.part_checksum == part->checksums.getTotalChecksumHex())
{
part->modification_time = part->getDataPartStorage().getLastModified().epochTime();
return part;
}
}
}
return {};
}
bool StorageReplicatedMergeTree::executeLogEntry(LogEntry & entry)
{
if (entry.type == LogEntry::DROP_RANGE || entry.type == LogEntry::DROP_PART)
{
executeDropRange(entry);
return true;
}
if (entry.type == LogEntry::REPLACE_RANGE)
{
executeReplaceRange(entry);
return true;
}
const bool is_get_or_attach = entry.type == LogEntry::GET_PART || entry.type == LogEntry::ATTACH_PART;
if (is_get_or_attach || entry.type == LogEntry::MERGE_PARTS || entry.type == LogEntry::MUTATE_PART)
{
/// If we already have this part or a part covering it, we do not need to do anything.
/// The part may be still in the PreActive -> Active transition so we first search
/// among PreActive parts to definitely find the desired part if it exists.
DataPartPtr existing_part = getPartIfExists(entry.new_part_name, {MergeTreeDataPartState::PreActive});
if (!existing_part)
existing_part = getActiveContainingPart(entry.new_part_name);
/// Even if the part is local, it (in exceptional cases) may not be in ZooKeeper. Let's check that it is there.
if (existing_part && getZooKeeper()->exists(fs::path(replica_path) / "parts" / existing_part->name))
{
if (!is_get_or_attach || entry.source_replica != replica_name)
LOG_DEBUG(log, "Skipping action for part {} because part {} already exists.",
entry.new_part_name, existing_part->name);
return true;
}
}
if (entry.type == LogEntry::ATTACH_PART)
{
ProfileEventsScope profile_events_scope;
if (MutableDataPartPtr part = attachPartHelperFoundValidPart(entry))
{
LOG_TRACE(log, "Found valid local part for {}, preparing the transaction", part->name);
Transaction transaction(*this, NO_TRANSACTION_RAW);
part->version.setCreationTID(Tx::PrehistoricTID, nullptr);
renameTempPartAndReplace(part, transaction);
checkPartChecksumsAndCommit(transaction, part);
writePartLog(PartLogElement::Type::NEW_PART, {}, 0 /** log entry is fake so we don't measure the time */,
part->name, part, {} /** log entry is fake so there are no initial parts */, nullptr,
profile_events_scope.getSnapshot());
return true;
}
LOG_TRACE(log, "Didn't find valid local part for {} ({}), will fetch it from other replica",
entry.new_part_name,
entry.actual_new_part_name);
}
if (is_get_or_attach && entry.source_replica == replica_name)
LOG_WARNING(log, "Part {} from own log doesn't exist.", entry.new_part_name);
/// Perhaps we don't need this part, because during write with quorum, the quorum has failed
/// (see below about `/quorum/failed_parts`).
if (entry.quorum && getZooKeeper()->exists(fs::path(zookeeper_path) / "quorum" / "failed_parts" / entry.new_part_name))
{
LOG_DEBUG(log, "Skipping action for part {} because quorum for that part was failed.", entry.new_part_name);
return true; /// NOTE Deletion from `virtual_parts` is not done, but it is only necessary for merge.
}
switch (entry.type)
{
case LogEntry::ATTACH_PART:
/// We surely don't have this part locally as we've checked it before, so download it.
[[fallthrough]];
case LogEntry::GET_PART:
return executeFetch(entry);
case LogEntry::MERGE_PARTS:
throw Exception(ErrorCodes::LOGICAL_ERROR, "Merge has to be executed by another function");
case LogEntry::MUTATE_PART:
throw Exception(ErrorCodes::LOGICAL_ERROR, "Mutation has to be executed by another function");
case LogEntry::ALTER_METADATA:
return executeMetadataAlter(entry);
case LogEntry::SYNC_PINNED_PART_UUIDS:
syncPinnedPartUUIDs();
return true;
case LogEntry::CLONE_PART_FROM_SHARD:
executeClonePartFromShard(entry);
return true;
default:
throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected log entry type: {}", static_cast<int>(entry.type));
}
}
bool StorageReplicatedMergeTree::executeFetch(LogEntry & entry, bool need_to_check_missing_part)
{
/// Looking for covering part. After that entry.actual_new_part_name may be filled.
String replica = findReplicaHavingCoveringPart(entry, true);
const auto storage_settings_ptr = getSettings();
auto metadata_snapshot = getInMemoryMetadataPtr();
try
{
if (replica.empty())
{
/** If a part is to be written with a quorum and the quorum is not reached yet,
* then (due to the fact that a part is impossible to download right now),
* the quorum entry should be considered unsuccessful.
* TODO Complex code, extract separately.
*/
if (entry.quorum)
{
if (entry.type != LogEntry::GET_PART)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Logical error: log entry with quorum but type is not GET_PART");
LOG_DEBUG(log, "No active replica has part {} which needs to be written with quorum. Will try to mark that quorum as failed.", entry.new_part_name);
/** Atomically:
* - if replicas do not become active;
* - if there is a `quorum` node with this part;
* - delete `quorum` node;
* - add a part to the list `quorum/failed_parts`;
* - if the part is not already removed from the list for deduplication `blocks/block_num`, then delete it;
*
* If something changes, then we will nothing - we'll get here again next time.
*/
/** We collect the `host` node versions from the replicas.
* When the replica becomes active, it changes the value of host in the same transaction (with the creation of `is_active`).
* This will ensure that the replicas do not become active.
*/
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
Coordination::Requests ops;
for (const auto & path_part : replicas)
{
Coordination::Stat stat;
String path = fs::path(zookeeper_path) / "replicas" / path_part / "host";
zookeeper->get(path, &stat);
ops.emplace_back(zkutil::makeCheckRequest(path, stat.version));
}
/// We verify that while we were collecting versions, the replica with the necessary part did not come alive.
replica = findReplicaHavingPart(entry.new_part_name, true);
/// Also during this time a completely new replica could be created.
/// But if a part does not appear on the old, then it can not be on the new one either.
if (replica.empty())
{
Coordination::Stat quorum_stat;
const String quorum_unparallel_path = fs::path(zookeeper_path) / "quorum" / "status";
const String quorum_parallel_path = fs::path(zookeeper_path) / "quorum" / "parallel" / entry.new_part_name;
String quorum_str, quorum_path;
ReplicatedMergeTreeQuorumEntry quorum_entry;
if (zookeeper->tryGet(quorum_unparallel_path, quorum_str, &quorum_stat))
quorum_path = quorum_unparallel_path;
else
{
quorum_str = zookeeper->get(quorum_parallel_path, &quorum_stat);
quorum_path = quorum_parallel_path;
}
quorum_entry.fromString(quorum_str);
if (quorum_entry.part_name == entry.new_part_name)
{
ops.emplace_back(zkutil::makeRemoveRequest(quorum_path, quorum_stat.version));
auto part_info = MergeTreePartInfo::fromPartName(entry.new_part_name, format_version);
if (part_info.min_block != part_info.max_block)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Logical error: log entry with quorum for part covering more than one block number");
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(zookeeper_path) / "quorum" / "failed_parts" / entry.new_part_name,
"",
zkutil::CreateMode::Persistent));
/// Deleting from `blocks`.
if (!entry.block_id.empty() && zookeeper->exists(fs::path(zookeeper_path) / "blocks" / entry.block_id))
ops.emplace_back(zkutil::makeRemoveRequest(fs::path(zookeeper_path) / "blocks" / entry.block_id, -1));
Coordination::Responses responses;
auto code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZOK)
{
LOG_DEBUG(log, "Marked quorum for part {} as failed.", entry.new_part_name);
queue.removeFailedQuorumPart(part_info);
return true;
}
else if (code == Coordination::Error::ZBADVERSION || code == Coordination::Error::ZNONODE || code == Coordination::Error::ZNODEEXISTS)
{
LOG_DEBUG(log, "State was changed or isn't expected when trying to mark quorum for part {} as failed. Code: {}",
entry.new_part_name, code);
}
else
throw Coordination::Exception(code);
}
else
{
LOG_WARNING(log, "No active replica has part {}, "
"but that part needs quorum and /quorum/status contains entry about another part {}. "
"It means that part was successfully written to {} replicas, but then all of them goes offline. "
"Or it is a bug.", entry.new_part_name, quorum_entry.part_name, entry.quorum);
}
}
}
if (replica.empty())
{
ProfileEvents::increment(ProfileEvents::ReplicatedPartFailedFetches);
if (!need_to_check_missing_part)
return false;
throw Exception(ErrorCodes::NO_REPLICA_HAS_PART, "No active replica has part {} or covering part (cannot execute {}: {})",
entry.new_part_name, entry.znode_name, entry.getDescriptionForLogs(format_version));
}
}
try
{
String part_name = entry.actual_new_part_name.empty() ? entry.new_part_name : entry.actual_new_part_name;
if (!entry.actual_new_part_name.empty())
LOG_DEBUG(log, "Will fetch part {} instead of {}", entry.actual_new_part_name, entry.new_part_name);
String source_replica_path = fs::path(zookeeper_path) / "replicas" / replica;
if (!fetchPart(part_name,
metadata_snapshot,
zookeeper_name,
source_replica_path,
/* to_detached= */ false,
entry.quorum,
/* zookeeper_ */ nullptr,
/* try_fetch_shared= */ true))
{
return false;
}
}
catch (Exception & e)
{
/// No stacktrace, just log message
if (e.code() == ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS)
e.addMessage("Too busy replica. Will try later.");
throw;
}
if (entry.type == LogEntry::MERGE_PARTS)
ProfileEvents::increment(ProfileEvents::ReplicatedPartFetchesOfMerged);
}
catch (...)
{
/** If we can not download the part we need for some merge, it's better not to try to get other parts for this merge,
* but try to get already merged part. To do this, move the action to get the remaining parts
* for this merge at the end of the queue.
*/
try
{
auto parts_for_merge = queue.moveSiblingPartsForMergeToEndOfQueue(entry.new_part_name);
if (!parts_for_merge.empty() && replica.empty())
{
LOG_INFO(log, "No active replica has part {}. Will fetch merged part instead.", entry.new_part_name);
/// We should enqueue it for check, because merged part may never appear if source part is lost
enqueuePartForCheck(entry.new_part_name);
return false;
}
/** If no active replica has a part, and there is no merge in the queue with its participation,
* check to see if any (active or inactive) replica has such a part or covering it.
*/
if (replica.empty())
enqueuePartForCheck(entry.new_part_name);
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
}
throw;
}
return true;
}
MergeTreeData::MutableDataPartPtr StorageReplicatedMergeTree::executeFetchShared(
const String & source_replica,
const String & new_part_name,
const DiskPtr & disk,
const String & path)
{
if (source_replica.empty())
{
LOG_INFO(log, "No active replica has part {} on shared storage.", new_part_name);
return nullptr;
}
const auto storage_settings_ptr = getSettings();
auto metadata_snapshot = getInMemoryMetadataPtr();
try
{
return fetchExistsPart(new_part_name, metadata_snapshot, fs::path(zookeeper_path) / "replicas" / source_replica, disk, path);
}
catch (Exception & e)
{
if (e.code() == ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS)
e.addMessage("Too busy replica. Will try later.");
tryLogCurrentException(log, __PRETTY_FUNCTION__);
throw;
}
}
static void paranoidCheckForCoveredPartsInZooKeeper(const StorageReplicatedMergeTree * storage, const ZooKeeperPtr & zookeeper, const String & replica_path,
MergeTreeDataFormatVersion format_version, const String & covering_part_name)
{
#ifdef ABORT_ON_LOGICAL_ERROR
constexpr bool paranoid_check_for_covered_parts_default = true;
#else
constexpr bool paranoid_check_for_covered_parts_default = false;
#endif
bool paranoid_check_for_covered_parts = Context::getGlobalContextInstance()->getConfigRef().getBool(
"replicated_merge_tree_paranoid_check_on_drop_range", paranoid_check_for_covered_parts_default);
if (!paranoid_check_for_covered_parts)
return;
/// FIXME https://github.com/ClickHouse/ClickHouse/issues/51182
if (storage->getSettings()->use_metadata_cache)
return;
auto drop_range_info = MergeTreePartInfo::fromPartName(covering_part_name, format_version);
Strings parts_remain = zookeeper->getChildren(replica_path + "/parts");
for (const auto & part_name : parts_remain)
{
auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
if (drop_range_info.contains(part_info))
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Part {} remains in ZooKeeper after DROP_RANGE {}", part_name, covering_part_name);
}
}
void StorageReplicatedMergeTree::executeDropRange(const LogEntry & entry)
{
LOG_TRACE(log, "Executing DROP_RANGE {}", entry.new_part_name);
/// Wait for loading of outdated parts because DROP_RANGE
/// command must be applied to all parts on disk.
waitForOutdatedPartsToBeLoaded();
auto drop_range_info = MergeTreePartInfo::fromPartName(entry.new_part_name, format_version);
getContext()->getMergeList().cancelInPartition(getStorageID(), drop_range_info.partition_id, drop_range_info.max_block);
{
auto pause_checking_parts = part_check_thread.pausePartsCheck();
queue.removePartProducingOpsInRange(getZooKeeper(), drop_range_info, entry);
part_check_thread.cancelRemovedPartsCheck(drop_range_info);
}
/// Delete the parts contained in the range to be deleted.
/// It's important that no old parts remain (after the merge), because otherwise,
/// after adding a new replica, this new replica downloads them, but does not delete them.
/// And, if you do not, the parts will come to life after the server is restarted.
/// Therefore, we use all data parts.
auto metadata_snapshot = getInMemoryMetadataPtr();
PartsToRemoveFromZooKeeper parts_to_remove;
{
auto data_parts_lock = lockParts();
parts_to_remove = removePartsInRangeFromWorkingSetAndGetPartsToRemoveFromZooKeeper(NO_TRANSACTION_RAW, drop_range_info, data_parts_lock);
if (parts_to_remove.empty())
{
if (!drop_range_info.isFakeDropRangePart())
LOG_INFO(log, "Log entry {} tried to drop single part {}, but part does not exist", entry.znode_name, entry.new_part_name);
return;
}
}
if (entry.detach)
LOG_DEBUG(log, "Detaching parts.");
else
LOG_DEBUG(log, "Removing parts.");
if (entry.detach)
{
/// If DETACH clone parts to detached/ directory
for (const auto & part : parts_to_remove)
{
if (auto part_to_detach = part.getPartIfItWasActive())
{
String part_dir = part_to_detach->getDataPartStorage().getPartDirectory();
LOG_INFO(log, "Detaching {}", part_dir);
auto holder = getTemporaryPartDirectoryHolder(String(DETACHED_DIR_NAME) + "/" + part_dir);
part_to_detach->makeCloneInDetached("", metadata_snapshot, /*disk_transaction*/ {});
}
}
}
/// Forcibly remove parts from ZooKeeper
removePartsFromZooKeeperWithRetries(parts_to_remove);
paranoidCheckForCoveredPartsInZooKeeper(this, getZooKeeper(), replica_path, format_version, entry.new_part_name);
if (entry.detach)
LOG_DEBUG(log, "Detached {} parts inside {}.", parts_to_remove.size(), entry.new_part_name);
else
LOG_DEBUG(log, "Removed {} parts inside {}.", parts_to_remove.size(), entry.new_part_name);
/// We want to remove dropped parts from disk as soon as possible
/// To be removed a partition should have zero refcount, therefore call the cleanup thread at exit
parts_to_remove.clear();
cleanup_thread.wakeup();
}
bool StorageReplicatedMergeTree::executeReplaceRange(const LogEntry & entry)
{
Stopwatch watch;
ProfileEventsScope profile_events_scope;
auto & entry_replace = *entry.replace_range_entry;
LOG_DEBUG(log, "Executing log entry {} to replace parts range {} with {} parts from {}.{}",
entry.znode_name, entry_replace.drop_range_part_name, entry_replace.new_part_names.size(),
entry_replace.from_database, entry_replace.from_table);
/// Wait for loading of outdated parts because REPLACE_RANGE
/// command must be applied to all parts on disk.
waitForOutdatedPartsToBeLoaded();
auto metadata_snapshot = getInMemoryMetadataPtr();
auto storage_settings_ptr = getSettings();
MergeTreePartInfo drop_range = MergeTreePartInfo::fromPartName(entry_replace.drop_range_part_name, format_version);
/// Range with only one block has special meaning: it's ATTACH PARTITION or MOVE PARTITION, so there is no drop range
bool replace = !LogEntry::ReplaceRangeEntry::isMovePartitionOrAttachFrom(drop_range);
if (replace)
{
getContext()->getMergeList().cancelInPartition(getStorageID(), drop_range.partition_id, drop_range.max_block);
auto pause_checking_parts = part_check_thread.pausePartsCheck();
queue.removePartProducingOpsInRange(getZooKeeper(), drop_range, entry);
part_check_thread.cancelRemovedPartsCheck(drop_range);
}
else
{
drop_range = {};
}
struct PartDescription
{
PartDescription(
size_t index_,
const String & src_part_name_,
const String & new_part_name_,
const String & checksum_hex_,
MergeTreeDataFormatVersion format_version)
: index(index_)
, src_part_name(src_part_name_)
, src_part_info(MergeTreePartInfo::fromPartName(src_part_name_, format_version))
, new_part_name(new_part_name_)
, new_part_info(MergeTreePartInfo::fromPartName(new_part_name_, format_version))
, checksum_hex(checksum_hex_)
{
}
size_t index; // in log entry arrays
String src_part_name;
MergeTreePartInfo src_part_info;
String new_part_name;
MergeTreePartInfo new_part_info;
String checksum_hex;
/// Part which will be committed
MutableDataPartPtr res_part;
/// We could find a covering part
MergeTreePartInfo found_new_part_info;
String found_new_part_name;
/// Hold pointer to part in source table if will clone it from local table
DataPartPtr src_table_part;
/// A replica that will be used to fetch part
String replica;
HardlinkedFiles hardlinked_files;
scope_guard temporary_part_lock;
};
using PartDescriptionPtr = std::shared_ptr<PartDescription>;
using PartDescriptions = std::vector<PartDescriptionPtr>;
PartDescriptions all_parts;
PartDescriptions parts_to_add;
PartsToRemoveFromZooKeeper parts_to_remove;
auto table_lock_holder_dst_table = lockForShare(
RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
auto dst_metadata_snapshot = getInMemoryMetadataPtr();
for (size_t i = 0; i < entry_replace.new_part_names.size(); ++i)
{
all_parts.emplace_back(std::make_shared<PartDescription>(i,
entry_replace.src_part_names.at(i),
entry_replace.new_part_names.at(i),
entry_replace.part_names_checksums.at(i),
format_version));
}
/// What parts we should add? Or we have already added all required parts (we an replica-initializer)
{
auto data_parts_lock = lockParts();
for (const PartDescriptionPtr & part_desc : all_parts)
{
if (!getActiveContainingPart(part_desc->new_part_info, MergeTreeDataPartState::Active, data_parts_lock))
parts_to_add.emplace_back(part_desc);
}
if (parts_to_add.empty() && replace)
{
parts_to_remove = removePartsInRangeFromWorkingSetAndGetPartsToRemoveFromZooKeeper(NO_TRANSACTION_RAW, drop_range, data_parts_lock);
String parts_to_remove_str;
for (const auto & part : parts_to_remove)
{
parts_to_remove_str += part.getPartName();
parts_to_remove_str += " ";
}
LOG_TRACE(log, "Replacing {} parts {}with empty set", parts_to_remove.size(), parts_to_remove_str);
}
}
if (parts_to_add.empty())
{
LOG_INFO(log, "All parts from REPLACE PARTITION command have been already attached");
removePartsFromZooKeeperWithRetries(parts_to_remove);
if (replace)
paranoidCheckForCoveredPartsInZooKeeper(this, getZooKeeper(), replica_path, format_version, entry_replace.drop_range_part_name);
return true;
}
if (parts_to_add.size() < all_parts.size())
{
LOG_WARNING(log, "Some (but not all) parts from REPLACE PARTITION command already exist. REPLACE PARTITION will not be atomic.");
}
StoragePtr source_table;
TableLockHolder table_lock_holder_src_table;
StorageID source_table_id{entry_replace.from_database, entry_replace.from_table};
auto clone_data_parts_from_source_table = [&] () -> size_t
{
source_table = DatabaseCatalog::instance().tryGetTable(source_table_id, getContext());
if (!source_table)
{
LOG_DEBUG(log, "Can't use {} as source table for REPLACE PARTITION command. It does not exist.", source_table_id.getNameForLogs());
return 0;
}
auto src_metadata_snapshot = source_table->getInMemoryMetadataPtr();
MergeTreeData * src_data = nullptr;
try
{
src_data = &checkStructureAndGetMergeTreeData(source_table, src_metadata_snapshot, dst_metadata_snapshot);
}
catch (Exception &)
{
LOG_INFO(log, "Can't use {} as source table for REPLACE PARTITION command. Will fetch all parts. Reason: {}", source_table_id.getNameForLogs(), getCurrentExceptionMessage(false));
return 0;
}
table_lock_holder_src_table = source_table->lockForShare(
RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
DataPartStates valid_states{
MergeTreeDataPartState::PreActive, MergeTreeDataPartState::Active, MergeTreeDataPartState::Outdated};
size_t num_clonable_parts = 0;
for (PartDescriptionPtr & part_desc : parts_to_add)
{
auto src_part = src_data->getPartIfExists(part_desc->src_part_info, valid_states);
if (!src_part)
{
LOG_DEBUG(log, "There is no part {} in {}", part_desc->src_part_name, source_table_id.getNameForLogs());
continue;
}
bool avoid_copy_local_part = storage_settings_ptr->allow_remote_fs_zero_copy_replication && src_part->isStoredOnRemoteDiskWithZeroCopySupport();
if (avoid_copy_local_part)
{
LOG_DEBUG(log, "Avoid copy local part {} from table {} because of zero-copy replication", part_desc->src_part_name, source_table_id.getNameForLogs());
continue;
}
String checksum_hex = src_part->checksums.getTotalChecksumHex();
if (checksum_hex != part_desc->checksum_hex)
{
LOG_DEBUG(log, "Part {} of {} has inappropriate checksum", part_desc->src_part_name, source_table_id.getNameForLogs());
/// TODO: check version
continue;
}
part_desc->found_new_part_name = part_desc->new_part_name;
part_desc->found_new_part_info = part_desc->new_part_info;
part_desc->src_table_part = src_part;
++num_clonable_parts;
}
return num_clonable_parts;
};
size_t num_clonable_parts = clone_data_parts_from_source_table();
LOG_DEBUG(log, "Found {} parts that could be cloned (of {} required parts)", num_clonable_parts, parts_to_add.size());
ActiveDataPartSet adding_parts_active_set(format_version);
std::unordered_map<String, PartDescriptionPtr> part_name_to_desc;
for (PartDescriptionPtr & part_desc : parts_to_add)
{
if (part_desc->src_table_part)
{
/// It is clonable part
adding_parts_active_set.add(part_desc->new_part_name);
part_name_to_desc.emplace(part_desc->new_part_name, part_desc);
continue;
}
/// Firstly, try find exact part to produce more accurate part set
String replica = findReplicaHavingPart(part_desc->new_part_name, true);
String found_part_name;
/// TODO: check version
if (replica.empty())
{
LOG_DEBUG(log, "Part {} is not found on remote replicas", part_desc->new_part_name);
/// Fallback to covering part
replica = findReplicaHavingCoveringPart(part_desc->new_part_name, true, found_part_name);
if (replica.empty())
{
/// It is not fail, since adjacent parts could cover current part
LOG_DEBUG(log, "Parts covering {} are not found on remote replicas", part_desc->new_part_name);
continue;
}
}
else
{
found_part_name = part_desc->new_part_name;
}
part_desc->found_new_part_name = found_part_name;
part_desc->found_new_part_info = MergeTreePartInfo::fromPartName(found_part_name, format_version);
part_desc->replica = replica;
adding_parts_active_set.add(part_desc->found_new_part_name);
part_name_to_desc.emplace(part_desc->found_new_part_name, part_desc);
}
/// Check that we could cover whole range
for (PartDescriptionPtr & part_desc : parts_to_add)
{
if (!adding_parts_active_set.getContainingPart(part_desc->new_part_info).empty())
continue;
MergeTreePartInfo covering_drop_range;
if (queue.isGoingToBeDropped(part_desc->new_part_info, &covering_drop_range))
{
LOG_WARNING(log, "Will not add part {} (while replacing {}) because it's going to be dropped (DROP_RANGE: {})",
part_desc->new_part_name, entry_replace.drop_range_part_name, covering_drop_range.getPartNameForLogs());
continue;
}
/// We should enqueue missing part for check, so it will be replaced with empty one (if needed)
/// and we will be able to execute this REPLACE_RANGE.
/// However, it's quite dangerous, because part may appear in source table.
/// So we enqueue it for check only if no replicas of source table have part either.
bool need_check = true;
if (auto * replicated_src_table = typeid_cast<StorageReplicatedMergeTree *>(source_table.get()))
{
String src_replica = replicated_src_table->findReplicaHavingPart(part_desc->src_part_name, false);
if (!src_replica.empty())
{
LOG_DEBUG(log, "Found part {} on replica {} of source table, will not check part {} required for {}",
part_desc->src_part_name, src_replica, part_desc->new_part_name, entry.znode_name);
need_check = false;
}
}
if (need_check)
{
LOG_DEBUG(log, "Will check part {} required for {}, because no replicas have it (including replicas of source table)",
part_desc->new_part_name, entry.znode_name);
enqueuePartForCheck(part_desc->new_part_name);
}
throw Exception(ErrorCodes::NO_REPLICA_HAS_PART,
"Not found part {} (or part covering it) neither source table neither remote replicas",
part_desc->new_part_name);
}
/// Filter covered parts
PartDescriptions final_parts;
Strings final_part_names;
{
final_part_names = adding_parts_active_set.getParts();
for (const String & final_part_name : final_part_names)
{
auto part_desc = part_name_to_desc[final_part_name];
if (!part_desc)
throw Exception(ErrorCodes::LOGICAL_ERROR, "There is no final part {}. This is a bug", final_part_name);
final_parts.emplace_back(part_desc);
if (final_parts.size() > 1)
{
auto & prev = *final_parts[final_parts.size() - 2];
auto & curr = *final_parts[final_parts.size() - 1];
if (!prev.found_new_part_info.isDisjoint(curr.found_new_part_info))
{
throw Exception(ErrorCodes::LOGICAL_ERROR, "Intersected final parts detected: {} and {}. It should be investigated.",
prev.found_new_part_name, curr.found_new_part_name);
}
}
}
}
static const String TMP_PREFIX = "tmp_replace_from_";
auto obtain_part = [&] (PartDescriptionPtr & part_desc)
{
/// Fetches with zero-copy-replication are cheap, but cloneAndLoadDataPartOnSameDisk will do full copy.
/// It's okay to check the setting for current table and disk for the source table, because src and dst part are on the same disk.
bool prefer_fetch_from_other_replica = !part_desc->replica.empty() && storage_settings_ptr->allow_remote_fs_zero_copy_replication
&& part_desc->src_table_part && part_desc->src_table_part->isStoredOnRemoteDiskWithZeroCopySupport();
if (part_desc->src_table_part && !prefer_fetch_from_other_replica)
{
if (part_desc->checksum_hex != part_desc->src_table_part->checksums.getTotalChecksumHex())
throw Exception(ErrorCodes::UNFINISHED, "Checksums of {} is suddenly changed", part_desc->src_table_part->name);
/// Don't do hardlinks in case of zero-copy at any side (defensive programming)
bool source_zero_copy_enabled = dynamic_cast<const MergeTreeData *>(source_table.get())->getSettings()->allow_remote_fs_zero_copy_replication;
bool our_zero_copy_enabled = storage_settings_ptr->allow_remote_fs_zero_copy_replication;
IDataPartStorage::ClonePartParams clone_params
{
.copy_instead_of_hardlink = (our_zero_copy_enabled || source_zero_copy_enabled) && part_desc->src_table_part->isStoredOnRemoteDiskWithZeroCopySupport(),
.metadata_version_to_write = metadata_snapshot->getMetadataVersion()
};
auto [res_part, temporary_part_lock] = cloneAndLoadDataPartOnSameDisk(
part_desc->src_table_part, TMP_PREFIX + "clone_", part_desc->new_part_info, metadata_snapshot, clone_params);
part_desc->res_part = std::move(res_part);
part_desc->temporary_part_lock = std::move(temporary_part_lock);
}
else if (!part_desc->replica.empty())
{
String source_replica_path = fs::path(zookeeper_path) / "replicas" / part_desc->replica;
ReplicatedMergeTreeAddress address(getZooKeeper()->get(fs::path(source_replica_path) / "host"));
auto timeouts = getFetchPartHTTPTimeouts(getContext());
auto credentials = getContext()->getInterserverCredentials();
String interserver_scheme = getContext()->getInterserverScheme();
scope_guard part_temp_directory_lock;
if (interserver_scheme != address.scheme)
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Interserver schemas are different '{}' != '{}', can't fetch part from {}",
interserver_scheme, address.scheme, address.host);
auto [fetched_part, lock] = fetcher.fetchSelectedPart(
metadata_snapshot, getContext(), part_desc->found_new_part_name, zookeeper_name, source_replica_path,
address.host, address.replication_port, timeouts, credentials->getUser(), credentials->getPassword(),
interserver_scheme, replicated_fetches_throttler, false, TMP_PREFIX + "fetch_");
part_desc->res_part = fetched_part;
part_temp_directory_lock = std::move(lock);
/// TODO: check columns_version of fetched part
ProfileEvents::increment(ProfileEvents::ReplicatedPartFetches);
}
else
throw Exception(ErrorCodes::LOGICAL_ERROR, "There is no receipt to produce part {}. This is bug", part_desc->new_part_name);
};
/// Download or clone parts
/// TODO: make it in parallel
for (PartDescriptionPtr & part_desc : final_parts)
obtain_part(part_desc);
MutableDataPartsVector res_parts;
for (PartDescriptionPtr & part_desc : final_parts)
res_parts.emplace_back(part_desc->res_part);
try
{
/// Commit parts
auto zookeeper = getZooKeeper();
Transaction transaction(*this, NO_TRANSACTION_RAW);
Coordination::Requests ops;
for (PartDescriptionPtr & part_desc : final_parts)
{
renameTempPartAndReplace(part_desc->res_part, transaction);
getCommitPartOps(ops, part_desc->res_part);
lockSharedData(*part_desc->res_part, false, part_desc->hardlinked_files);
}
if (!ops.empty())
zookeeper->multi(ops);
{
auto data_parts_lock = lockParts();
transaction.commit(&data_parts_lock);
if (replace)
{
parts_to_remove = removePartsInRangeFromWorkingSetAndGetPartsToRemoveFromZooKeeper(NO_TRANSACTION_RAW, drop_range, data_parts_lock);
String parts_to_remove_str;
for (const auto & part : parts_to_remove)
{
parts_to_remove_str += part.getPartName();
parts_to_remove_str += " ";
}
LOG_TRACE(log, "Replacing {} parts {}with {} parts {}", parts_to_remove.size(), parts_to_remove_str,
final_parts.size(), boost::algorithm::join(final_part_names, ", "));
}
}
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(res_parts, watch.elapsed(), profile_events_scope.getSnapshot()));
}
catch (...)
{
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(res_parts, watch.elapsed()), ExecutionStatus::fromCurrentException("", true));
for (const auto & res_part : res_parts)
unlockSharedData(*res_part);
throw;
}
removePartsFromZooKeeperWithRetries(parts_to_remove);
if (replace)
paranoidCheckForCoveredPartsInZooKeeper(this, getZooKeeper(), replica_path, format_version, entry_replace.drop_range_part_name);
res_parts.clear();
parts_to_remove.clear();
cleanup_thread.wakeup();
return true;
}
void StorageReplicatedMergeTree::executeClonePartFromShard(const LogEntry & entry)
{
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(entry.source_shard + "/replicas");
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
String replica;
for (const String & candidate : replicas)
{
if (zookeeper->exists(entry.source_shard + "/replicas/" + candidate + "/is_active"))
{
replica = candidate;
break;
}
}
if (replica.empty())
throw Exception(ErrorCodes::NO_REPLICA_HAS_PART, "Not found active replica on shard {} to clone part {}",
entry.source_shard, entry.new_part_name);
LOG_INFO(log, "Will clone part from shard {} and replica {}", entry.source_shard, replica);
MutableDataPartPtr part;
{
auto metadata_snapshot = getInMemoryMetadataPtr();
String source_replica_path = entry.source_shard + "/replicas/" + replica;
ReplicatedMergeTreeAddress address(getZooKeeper()->get(source_replica_path + "/host"));
auto timeouts = getHTTPTimeouts(getContext());
auto credentials = getContext()->getInterserverCredentials();
String interserver_scheme = getContext()->getInterserverScheme();
scope_guard part_temp_directory_lock;
auto get_part = [&, address, timeouts, credentials, interserver_scheme]()
{
if (interserver_scheme != address.scheme)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Interserver schemes are different: '{}' != '{}', can't fetch part from {}",
interserver_scheme, address.scheme, address.host);
auto [fetched_part, lock] = fetcher.fetchSelectedPart(
metadata_snapshot, getContext(), entry.new_part_name, zookeeper_name, source_replica_path,
address.host, address.replication_port,
timeouts, credentials->getUser(), credentials->getPassword(), interserver_scheme,
replicated_fetches_throttler, true);
part_temp_directory_lock = std::move(lock);
return fetched_part;
};
part = get_part();
// The fetched part is valuable and should not be cleaned like a temp part.
part->is_temp = false;
part->renameTo("detached/" + entry.new_part_name, true);
LOG_INFO(log, "Cloned part {} to detached directory", part->name);
}
}
void StorageReplicatedMergeTree::cloneReplica(const String & source_replica, Coordination::Stat source_is_lost_stat, zkutil::ZooKeeperPtr & zookeeper)
{
String source_path = fs::path(zookeeper_path) / "replicas" / source_replica;
/// The order of the following three actions is important.
Strings source_queue_names;
/// We are trying to get consistent /log_pointer and /queue state. Otherwise
/// we can possibly duplicate entries in queue of cloned replica.
while (true)
{
Coordination::Stat log_pointer_stat;
String raw_log_pointer = zookeeper->get(fs::path(source_path) / "log_pointer", &log_pointer_stat);
Coordination::Requests ops;
ops.push_back(zkutil::makeSetRequest(fs::path(replica_path) / "log_pointer", raw_log_pointer, -1));
/// For support old versions CH.
if (source_is_lost_stat.version == -1)
{
/// We check that it was not suddenly upgraded to new version.
/// Otherwise it can be upgraded and instantly become lost, but we cannot notice that.
zkutil::addCheckNotExistsRequest(ops, *zookeeper, fs::path(source_path) / "is_lost");
}
else /// The replica we clone should not suddenly become lost.
ops.push_back(zkutil::makeCheckRequest(fs::path(source_path) / "is_lost", source_is_lost_stat.version));
Coordination::Responses responses;
/// Let's remember the queue of the reference/master replica.
source_queue_names = zookeeper->getChildren(fs::path(source_path) / "queue");
/// Check that log pointer of source replica didn't changed while we read queue entries
ops.push_back(zkutil::makeCheckRequest(fs::path(source_path) / "log_pointer", log_pointer_stat.version));
auto rc = zookeeper->tryMulti(ops, responses);
if (rc == Coordination::Error::ZOK)
{
break;
}
else if (rc == Coordination::Error::ZNODEEXISTS)
{
throw Exception(ErrorCodes::REPLICA_STATUS_CHANGED,
"Can not clone replica, because the {} updated to new ClickHouse version", source_replica);
}
else if (responses[1]->error == Coordination::Error::ZBADVERSION)
{
/// If is_lost node version changed than source replica also lost,
/// so we cannot clone from it.
throw Exception(ErrorCodes::REPLICA_STATUS_CHANGED, "Can not clone replica, because the {} became lost",
source_replica);
}
else if (responses.back()->error == Coordination::Error::ZBADVERSION)
{
/// If source replica's log_pointer changed than we probably read
/// stale state of /queue and have to try one more time.
LOG_WARNING(log, "Log pointer of source replica {} changed while we loading queue nodes. Will retry.", source_replica);
continue;
}
else
{
zkutil::KeeperMultiException::check(rc, ops, responses);
}
}
::sort(source_queue_names.begin(), source_queue_names.end());
struct QueueEntryInfo
{
String data = {};
Coordination::Stat stat = {};
LogEntryPtr parsed_entry = {};
};
/// We got log pointer and list of queue entries of source replica.
/// At first we will get queue entries and then we will get list of active parts of source replica
/// to enqueue fetches for missing parts. If source replica executes and removes some entry concurrently
/// we will see produced part (or covering part) in replicas/source/parts and will enqueue fetch.
/// We will try to parse queue entries before copying them
/// to avoid creation of excessive and duplicating entries in our queue.
/// See also removePartAndEnqueueFetch(...)
std::vector<QueueEntryInfo> source_queue;
ActiveDataPartSet get_part_set{format_version};
ActiveDataPartSet drop_range_set{format_version};
std::unordered_set<String> exact_part_names;
{
std::vector<zkutil::ZooKeeper::FutureGet> queue_get_futures;
queue_get_futures.reserve(source_queue_names.size());
for (const String & entry_name : source_queue_names)
queue_get_futures.push_back(zookeeper->asyncTryGet(fs::path(source_path) / "queue" / entry_name));
source_queue.reserve(source_queue_names.size());
for (size_t i = 0; i < source_queue_names.size(); ++i)
{
auto res = queue_get_futures[i].get();
/// It's ok if entry is already executed and removed: we also will get source parts set.
if (res.error == Coordination::Error::ZNONODE)
continue;
assert(res.error == Coordination::Error::ZOK);
source_queue.emplace_back();
auto & info = source_queue.back();
info.data = std::move(res.data);
info.stat = std::move(res.stat);
try
{
info.parsed_entry = LogEntry::parse(info.data, info.stat, format_version);
}
catch (...)
{
tryLogCurrentException(log, "Cannot parse source queue entry " + source_queue_names[i]);
}
/// It may be ok if source replica has newer version. We will copy entry as is.
if (!info.parsed_entry)
continue;
info.parsed_entry->znode_name = source_queue_names[i];
if (info.parsed_entry->type == LogEntry::DROP_RANGE || info.parsed_entry->type == LogEntry::DROP_PART)
{
drop_range_set.add(info.parsed_entry->new_part_name);
}
else if (info.parsed_entry->type == LogEntry::GET_PART)
{
String maybe_covering_drop_range = drop_range_set.getContainingPart(info.parsed_entry->new_part_name);
if (maybe_covering_drop_range.empty())
get_part_set.add(info.parsed_entry->new_part_name);
}
else
{
/// We should keep local parts if they present in the queue of source replica.
/// There's a chance that we are the only replica that has these parts.
Strings entry_virtual_parts = info.parsed_entry->getVirtualPartNames(format_version);
std::move(entry_virtual_parts.begin(), entry_virtual_parts.end(), std::inserter(exact_part_names, exact_part_names.end()));
}
}
}
/// We should do it after copying queue, because some ALTER_METADATA entries can be lost otherwise.
cloneMetadataIfNeeded(source_replica, source_path, zookeeper);
/// Add to the queue jobs to receive all the active parts that the reference/master replica has.
Strings source_replica_parts = zookeeper->getChildren(fs::path(source_path) / "parts");
for (const auto & active_part : source_replica_parts)
get_part_set.add(active_part);
Strings active_parts = get_part_set.getParts();
/// Remove local parts if source replica does not have them, because such parts will never be fetched by other replicas.
Strings local_parts_in_zk = zookeeper->getChildren(fs::path(replica_path) / "parts");
Strings parts_to_remove_from_zk;
for (const auto & part : local_parts_in_zk)
{
/// We look for exact match (and not for any covering part)
/// because our part might be dropped and covering part might be merged though gap.
/// (avoid resurrection of data that was removed a long time ago)
if (get_part_set.getContainingPart(part) == part)
continue;
if (exact_part_names.contains(part))
continue;
parts_to_remove_from_zk.emplace_back(part);
LOG_WARNING(log, "Source replica does not have part {}. Removing it from ZooKeeper.", part);
}
{
/// Check "is_lost" version after retrieving queue and parts.
/// If version has changed, then replica most likely has been dropped and parts set is inconsistent,
/// so throw exception and retry cloning.
Coordination::Stat is_lost_stat_new;
zookeeper->get(fs::path(source_path) / "is_lost", &is_lost_stat_new);
if (is_lost_stat_new.version != source_is_lost_stat.version)
throw Exception(ErrorCodes::REPLICA_STATUS_CHANGED, "Cannot clone {}, because it suddenly become lost "
"or removed broken part from ZooKeeper", source_replica);
}
removePartsFromZooKeeperWithRetries(parts_to_remove_from_zk);
auto local_active_parts = getDataPartsForInternalUsage();
DataPartsVector parts_to_remove_from_working_set;
for (const auto & part : local_active_parts)
{
if (get_part_set.getContainingPart(part->name) == part->name)
continue;
if (exact_part_names.contains(part->name))
continue;
parts_to_remove_from_working_set.emplace_back(part);
LOG_WARNING(log, "Source replica does not have part {}. Removing it from working set.", part->name);
}
if (getSettings()->detach_old_local_parts_when_cloning_replica)
{
auto metadata_snapshot = getInMemoryMetadataPtr();
for (const auto & part : parts_to_remove_from_working_set)
{
LOG_INFO(log, "Detaching {}", part->getDataPartStorage().getPartDirectory());
part->makeCloneInDetached("clone", metadata_snapshot, /*disk_transaction*/ {});
}
}
removePartsFromWorkingSet(NO_TRANSACTION_RAW, parts_to_remove_from_working_set, true);
std::unordered_set<String> created_get_parts;
/// Avoid creation of GET_PART entries which covered by another GET_PART or DROP_RANGE
/// and creation of multiple entries with the same new_part_name.
auto should_ignore_log_entry = [&drop_range_set, &get_part_set, this] (std::unordered_set<String> & created_gets,
const String & part_name, const String & log_msg_context) -> bool
{
/// We should not create entries covered by DROP_RANGE, because we will remove them anyway (kind of optimization).
String covering_drop_range = drop_range_set.getContainingPart(part_name);
if (!covering_drop_range.empty())
{
LOG_TRACE(log, "{} {}: it's covered by drop range {}", log_msg_context, part_name, covering_drop_range);
return true;
}
/// We should not create entries covered by GET_PART,
/// because GET_PART entry has no source parts and we can execute it only by fetching.
/// Parts covered by GET_PART are useless and may cause replication to stuck if covered part is lost.
String covering_get_part_entry = get_part_set.getContainingPart(part_name);
if (covering_get_part_entry.empty())
return false;
if (covering_get_part_entry != part_name)
{
LOG_TRACE(log, "{} {}: it's covered by GET_PART {}", log_msg_context, part_name, covering_get_part_entry);
return true;
}
/// NOTE: It does not completely avoids duplication of GET_PART entries,
/// because it's possible that source replica has executed some GET_PART after we copied it's queue,
/// but before we copied its active parts set. In this case we will GET_PART entry in our queue
/// and later will pull the original GET_PART from replication log.
/// It should not cause any issues, but it does not allow to get rid of duplicated entries and add an assertion.
if (created_gets.contains(part_name))
{
/// NOTE It would be better to copy log entry instead of creating GET_PART
/// if there are GET_PART and log entry of other type with the same new_part_name.
/// But it's a bit harder to implement, because it requires full-fledged virtual_parts set.
LOG_TRACE(log, "{} {}: GET_PART for it is already created", log_msg_context, part_name);
return true;
}
return false;
};
for (const String & name : active_parts)
{
if (should_ignore_log_entry(created_get_parts, name, "Not fetching"))
continue;
LogEntry log_entry;
if (are_restoring_replica)
{
LOG_DEBUG(log, "Obtaining checksum for path {}", name);
// The part we want to fetch is probably present in detached/ folder.
// However, we need to get part's checksum to check if it's not corrupt.
log_entry.type = LogEntry::ATTACH_PART;
MinimalisticDataPartChecksums desired_checksums;
const fs::path part_path = fs::path(source_path) / "parts" / name;
const String part_znode = zookeeper->get(part_path);
if (!part_znode.empty())
desired_checksums = ReplicatedMergeTreePartHeader::fromString(part_znode).getChecksums();
else
{
String desired_checksums_str = zookeeper->get(part_path / "checksums");
desired_checksums = MinimalisticDataPartChecksums::deserializeFrom(desired_checksums_str);
}
log_entry.part_checksum = getHexUIntUppercase(desired_checksums.hash_of_all_files);
}
else
{
log_entry.type = LogEntry::GET_PART;
}
log_entry.source_replica = "";
log_entry.new_part_name = name;
log_entry.create_time = tryGetPartCreateTime(zookeeper, source_path, name);
LOG_TEST(log, "Enqueueing {} for fetch", name);
zookeeper->create(fs::path(replica_path) / "queue/queue-", log_entry.toString(), zkutil::CreateMode::PersistentSequential);
created_get_parts.insert(name);
}
size_t total_parts_to_fetch = created_get_parts.size();
LOG_DEBUG(log, "Queued {} parts to be fetched, {} parts ignored", total_parts_to_fetch, active_parts.size() - total_parts_to_fetch);
/// Add content of the reference/master replica queue to the queue.
size_t total_entries_to_copy = 0;
for (const auto & entry_info : source_queue)
{
assert(!entry_info.data.empty());
if (entry_info.parsed_entry && !entry_info.parsed_entry->new_part_name.empty())
{
const String & part_name = entry_info.parsed_entry->new_part_name;
const String & entry_name = entry_info.parsed_entry->znode_name;
const auto & entry_type = entry_info.parsed_entry->type;
if (should_ignore_log_entry(created_get_parts, part_name, fmt::format("Not copying {} {}", entry_name, entry_type)))
continue;
if (entry_info.parsed_entry->type == LogEntry::GET_PART)
created_get_parts.insert(part_name);
}
LOG_TEST(log, "Copying entry {}", entry_info.data);
zookeeper->create(fs::path(replica_path) / "queue/queue-", entry_info.data, zkutil::CreateMode::PersistentSequential);
++total_entries_to_copy;
}
LOG_DEBUG(log, "Copied {} queue entries, {} entries ignored", total_entries_to_copy, source_queue.size() - total_entries_to_copy);
LOG_TRACE(log, "Parts in ZooKeeper after mimic: {}", fmt::join(zookeeper->getChildren(replica_path + "/parts"), ", "));
LOG_TRACE(log, "Enqueued fetches after mimic: {}", fmt::join(created_get_parts, ", "));
}
void StorageReplicatedMergeTree::cloneMetadataIfNeeded(const String & source_replica, const String & source_path, zkutil::ZooKeeperPtr & zookeeper)
{
String source_metadata_version_str;
bool metadata_version_exists = zookeeper->tryGet(source_path + "/metadata_version", source_metadata_version_str);
if (!metadata_version_exists)
{
/// For compatibility with version older than 20.3
/// TODO fix tests and delete it
LOG_WARNING(log, "Node {} does not exist. "
"Most likely it's because too old version of ClickHouse is running on replica {}. "
"Will not check metadata consistency",
source_path + "/metadata_version", source_replica);
return;
}
auto metadata_snapshot = getInMemoryMetadataPtr();
Int32 source_metadata_version = parse<Int32>(source_metadata_version_str);
if (metadata_snapshot->getMetadataVersion() == source_metadata_version)
return;
/// Our metadata it not up to date with source replica metadata.
/// Metadata is updated by ALTER_METADATA entries, but some entries are probably cleaned up from the log.
/// It's also possible that some newer ALTER_METADATA entries are present in source_queue list,
/// and source replica are executing such entry right now (or had executed recently).
/// More than that, /metadata_version update is not atomic with /columns and /metadata update...
/// Fortunately, ALTER_METADATA seems to be idempotent,
/// and older entries of such type can be replaced with newer entries.
/// Let's try to get consistent values of source replica's /columns and /metadata
/// and prepend dummy ALTER_METADATA to our replication queue.
/// It should not break anything if source_queue already contains ALTER_METADATA entry
/// with greater or equal metadata_version, but it will update our metadata
/// if all such entries were cleaned up from the log and source_queue.
LOG_WARNING(log, "Metadata version ({}) on replica is not up to date with metadata ({}) on source replica {}",
metadata_snapshot->getMetadataVersion(), source_metadata_version, source_replica);
String source_metadata;
String source_columns;
while (true)
{
Coordination::Stat metadata_stat;
Coordination::Stat columns_stat;
source_metadata = zookeeper->get(source_path + "/metadata", &metadata_stat);
source_columns = zookeeper->get(source_path + "/columns", &columns_stat);
Coordination::Requests ops;
Coordination::Responses responses;
ops.emplace_back(zkutil::makeCheckRequest(source_path + "/metadata", metadata_stat.version));
ops.emplace_back(zkutil::makeCheckRequest(source_path + "/columns", columns_stat.version));
Coordination::Error code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZOK)
break;
else if (code == Coordination::Error::ZBADVERSION)
LOG_WARNING(log, "Metadata of replica {} was changed", source_path);
else
zkutil::KeeperMultiException::check(code, ops, responses);
}
ReplicatedMergeTreeLogEntryData dummy_alter;
dummy_alter.type = LogEntry::ALTER_METADATA;
dummy_alter.source_replica = source_replica;
dummy_alter.metadata_str = source_metadata;
dummy_alter.columns_str = source_columns;
dummy_alter.alter_version = source_metadata_version;
dummy_alter.create_time = time(nullptr);
String path_created = zookeeper->create(replica_path + "/queue/queue-", dummy_alter.toString(), zkutil::CreateMode::PersistentSequential);
LOG_INFO(log, "Created an ALTER_METADATA entry {} to force metadata update after cloning replica from {}. Entry: {}",
path_created, source_replica, dummy_alter.toString());
/// We don't need to do anything with mutation_pointer, because mutation log cleanup process is different from
/// replication log cleanup. A mutation is removed from ZooKeeper only if all replicas had executed the mutation,
/// so all mutations which are greater or equal to our mutation pointer are still present in ZooKeeper.
}
void StorageReplicatedMergeTree::cloneReplicaIfNeeded(zkutil::ZooKeeperPtr zookeeper)
{
Coordination::Stat is_lost_stat;
bool is_new_replica = true;
String res;
if (zookeeper->tryGet(fs::path(replica_path) / "is_lost", res, &is_lost_stat))
{
if (res == "0")
return;
if (is_lost_stat.version)
is_new_replica = false;
}
else
{
/// Replica was created by old version of CH, so me must create "/is_lost".
/// Note that in old version of CH there was no "lost" replicas possible.
/// TODO is_lost node should always exist since v18.12, maybe we can replace `tryGet` with `get` and remove old code?
zookeeper->create(fs::path(replica_path) / "is_lost", "0", zkutil::CreateMode::Persistent);
return;
}
/// is_lost is "1": it means that we are in repair mode.
/// Try choose source replica to clone.
/// Source replica must not be lost and should have minimal queue size and maximal log pointer.
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
std::vector<zkutil::ZooKeeper::FutureGet> futures;
for (const String & source_replica_name : replicas)
{
/// Do not clone from myself.
if (source_replica_name == replica_name)
continue;
String source_replica_path = fs::path(zookeeper_path) / "replicas" / source_replica_name;
/// Obviously the following get operations are not atomic, but it's ok to choose good enough replica, not the best one.
/// NOTE: We may count some entries twice if log_pointer is moved.
futures.emplace_back(zookeeper->asyncTryGet(fs::path(source_replica_path) / "is_lost"));
futures.emplace_back(zookeeper->asyncTryGet(fs::path(source_replica_path) / "log_pointer"));
futures.emplace_back(zookeeper->asyncTryGet(fs::path(source_replica_path) / "queue"));
}
/// Wait for results before getting log entries
for (auto & future : futures)
future.wait();
Strings log_entries = zookeeper->getChildren(fs::path(zookeeper_path) / "log");
size_t max_log_entry = 0;
if (!log_entries.empty())
{
String last_entry = *std::max_element(log_entries.begin(), log_entries.end());
max_log_entry = parse<UInt64>(last_entry.substr(strlen("log-")));
}
/// log_pointer can point to future entry, which was not created yet
++max_log_entry;
size_t min_replication_lag = std::numeric_limits<size_t>::max();
String source_replica;
Coordination::Stat source_is_lost_stat;
size_t future_num = 0;
for (const String & source_replica_name : replicas)
{
if (source_replica_name == replica_name)
continue;
auto get_is_lost = futures[future_num++].get();
auto get_log_pointer = futures[future_num++].get();
auto get_queue = futures[future_num++].get();
if (get_is_lost.error != Coordination::Error::ZOK)
{
LOG_INFO(log, "Not cloning {}, cannot get '/is_lost': {}", source_replica_name, get_is_lost.error);
continue;
}
else if (get_is_lost.data != "0")
{
LOG_INFO(log, "Not cloning {}, it's lost", source_replica_name);
continue;
}
if (get_log_pointer.error != Coordination::Error::ZOK)
{
LOG_INFO(log, "Not cloning {}, cannot get '/log_pointer': {}", source_replica_name, get_log_pointer.error);
continue;
}
if (get_queue.error != Coordination::Error::ZOK)
{
LOG_INFO(log, "Not cloning {}, cannot get '/queue': {}", source_replica_name, get_queue.error);
continue;
}
/// Replica is not lost and we can clone it. Let's calculate approx replication lag.
size_t source_log_pointer = get_log_pointer.data.empty() ? 0 : parse<UInt64>(get_log_pointer.data);
assert(source_log_pointer <= max_log_entry);
size_t replica_queue_lag = max_log_entry - source_log_pointer;
size_t replica_queue_size = get_queue.stat.numChildren;
size_t replication_lag = replica_queue_lag + replica_queue_size;
LOG_INFO(log, "Replica {} has log pointer '{}', approximate {} queue lag and {} queue size",
source_replica_name, get_log_pointer.data, replica_queue_lag, replica_queue_size);
if (replication_lag < min_replication_lag)
{
source_replica = source_replica_name;
source_is_lost_stat = get_is_lost.stat;
min_replication_lag = replication_lag;
}
}
if (source_replica.empty())
throw Exception(ErrorCodes::ALL_REPLICAS_LOST, "All replicas are lost. "
"See SYSTEM DROP REPLICA and SYSTEM RESTORE REPLICA queries, they may help");
if (is_new_replica)
LOG_INFO(log, "Will mimic {}", source_replica);
else
LOG_WARNING(log, "Will mimic {}", source_replica);
/// Clear obsolete queue that we no longer need.
zookeeper->removeChildren(fs::path(replica_path) / "queue");
queue.clear();
/// Will do repair from the selected replica.
cloneReplica(source_replica, source_is_lost_stat, zookeeper);
/// If repair fails to whatever reason, the exception is thrown, is_lost will remain "1" and the replica will be repaired later.
/// If replica is repaired successfully, we remove is_lost flag.
zookeeper->set(fs::path(replica_path) / "is_lost", "0");
}
String StorageReplicatedMergeTree::getLastQueueUpdateException() const
{
std::lock_guard lock(last_queue_update_exception_lock);
return last_queue_update_exception;
}
void StorageReplicatedMergeTree::queueUpdatingTask()
{
if (!queue_update_in_progress)
{
last_queue_update_start_time.store(time(nullptr));
queue_update_in_progress = true;
}
try
{
queue.pullLogsToQueue(getZooKeeperAndAssertNotReadonly(), queue_updating_task->getWatchCallback(), ReplicatedMergeTreeQueue::UPDATE);
last_queue_update_finish_time.store(time(nullptr));
queue_update_in_progress = false;
}
catch (const Coordination::Exception & e)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
std::lock_guard lock(last_queue_update_exception_lock);
last_queue_update_exception = getCurrentExceptionMessage(false);
if (e.code == Coordination::Error::ZSESSIONEXPIRED)
{
restarting_thread.wakeup();
return;
}
queue_updating_task->scheduleAfter(QUEUE_UPDATE_ERROR_SLEEP_MS);
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
std::lock_guard lock(last_queue_update_exception_lock);
last_queue_update_exception = getCurrentExceptionMessage(false);
queue_updating_task->scheduleAfter(QUEUE_UPDATE_ERROR_SLEEP_MS);
}
}
void StorageReplicatedMergeTree::mutationsUpdatingTask()
{
try
{
queue.updateMutations(getZooKeeper(), mutations_watch_callback);
}
catch (const Coordination::Exception & e)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
if (e.code == Coordination::Error::ZSESSIONEXPIRED)
return;
mutations_updating_task->scheduleAfter(QUEUE_UPDATE_ERROR_SLEEP_MS);
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
mutations_updating_task->scheduleAfter(QUEUE_UPDATE_ERROR_SLEEP_MS);
}
}
ReplicatedMergeTreeQueue::SelectedEntryPtr StorageReplicatedMergeTree::selectQueueEntry()
{
/// This object will mark the element of the queue as running.
ReplicatedMergeTreeQueue::SelectedEntryPtr selected;
try
{
selected = queue.selectEntryToProcess(merger_mutator, *this);
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
}
return selected;
}
bool StorageReplicatedMergeTree::processQueueEntry(ReplicatedMergeTreeQueue::SelectedEntryPtr selected_entry)
{
LogEntryPtr & entry = selected_entry->log_entry;
return queue.processEntry([this]{ return getZooKeeper(); }, entry, [&](LogEntryPtr & entry_to_process)
{
try
{
return executeLogEntry(*entry_to_process);
}
catch (const Exception & e)
{
if (e.code() == ErrorCodes::NO_REPLICA_HAS_PART)
{
/// If no one has the right part, probably not all replicas work; We will not write to log with Error level.
LOG_INFO(log, getExceptionMessageAndPattern(e, /* with_stacktrace */ false));
}
else if (e.code() == ErrorCodes::ABORTED)
{
/// Interrupted merge or downloading a part is not an error.
LOG_INFO(log, getExceptionMessageAndPattern(e, /* with_stacktrace */ false));
}
else if (e.code() == ErrorCodes::PART_IS_TEMPORARILY_LOCKED)
{
/// Part cannot be added temporarily
LOG_INFO(log, getExceptionMessageAndPattern(e, /* with_stacktrace */ false));
cleanup_thread.wakeup();
}
else
tryLogCurrentException(log, __PRETTY_FUNCTION__);
/** This exception will be written to the queue element, and it can be looked up using `system.replication_queue` table.
* The thread that performs this action will sleep a few seconds after the exception.
* See `queue.processEntry` function.
*/
throw;
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
throw;
}
});
}
bool StorageReplicatedMergeTree::scheduleDataProcessingJob(BackgroundJobsAssignee & assignee)
{
cleanup_thread.wakeupEarlierIfNeeded();
/// If replication queue is stopped exit immediately as we successfully executed the task
if (queue.actions_blocker.isCancelled())
return false;
/// This object will mark the element of the queue as running.
ReplicatedMergeTreeQueue::SelectedEntryPtr selected_entry = selectQueueEntry();
if (!selected_entry)
return false;
auto job_type = selected_entry->log_entry->type;
/// Depending on entry type execute in fetches (small) pool or big merge_mutate pool
if (job_type == LogEntry::GET_PART || job_type == LogEntry::ATTACH_PART)
{
assignee.scheduleFetchTask(std::make_shared<ExecutableLambdaAdapter>(
[this, selected_entry] () mutable
{
return processQueueEntry(selected_entry);
}, common_assignee_trigger, getStorageID()));
return true;
}
else if (job_type == LogEntry::MERGE_PARTS)
{
auto task = std::make_shared<MergeFromLogEntryTask>(selected_entry, *this, common_assignee_trigger);
assignee.scheduleMergeMutateTask(task);
return true;
}
else if (job_type == LogEntry::MUTATE_PART)
{
auto task = std::make_shared<MutateFromLogEntryTask>(selected_entry, *this, common_assignee_trigger);
assignee.scheduleMergeMutateTask(task);
return true;
}
else
{
assignee.scheduleCommonTask(std::make_shared<ExecutableLambdaAdapter>(
[this, selected_entry] () mutable
{
return processQueueEntry(selected_entry);
}, common_assignee_trigger, getStorageID()), /* need_trigger */ true);
return true;
}
}
bool StorageReplicatedMergeTree::canExecuteFetch(const ReplicatedMergeTreeLogEntry & entry, String & disable_reason) const
{
if (fetcher.blocker.isCancelled())
{
disable_reason = fmt::format("Not executing fetch of part {} because replicated fetches are cancelled now.", entry.new_part_name);
return false;
}
auto replicated_fetches_pool_size = getContext()->getFetchesExecutor()->getMaxTasksCount();
size_t busy_threads_in_pool = CurrentMetrics::values[CurrentMetrics::BackgroundFetchesPoolTask].load(std::memory_order_relaxed);
if (busy_threads_in_pool >= replicated_fetches_pool_size)
{
disable_reason = fmt::format("Not executing fetch of part {} because {} fetches already executing, max {}.", entry.new_part_name, busy_threads_in_pool, replicated_fetches_pool_size);
return false;
}
if (replicated_fetches_throttler->isThrottling())
{
disable_reason = fmt::format("Not executing fetch of part {} because fetches have already throttled by network settings "
"<max_replicated_fetches_network_bandwidth> or <max_replicated_fetches_network_bandwidth_for_server>.", entry.new_part_name);
return false;
}
if (entry.source_replica.empty())
{
auto part = getPartIfExists(entry.new_part_name, {MergeTreeDataPartState::Active, MergeTreeDataPartState::Outdated, MergeTreeDataPartState::Deleting});
if (part && part->was_removed_as_broken)
{
disable_reason = fmt::format("Not executing fetch of part {} because we still have broken part with that name. "
"Waiting for the broken part to be removed first.", entry.new_part_name);
constexpr time_t min_interval_to_wakeup_cleanup_s = 30;
if (entry.last_postpone_time + min_interval_to_wakeup_cleanup_s < time(nullptr))
const_cast<StorageReplicatedMergeTree *>(this)->cleanup_thread.wakeup();
return false;
}
}
return true;
}
bool StorageReplicatedMergeTree::partIsAssignedToBackgroundOperation(const DataPartPtr & part) const
{
return queue.isVirtualPart(part);
}
void StorageReplicatedMergeTree::mergeSelectingTask()
{
if (!is_leader)
return;
const auto storage_settings_ptr = getSettings();
const bool deduplicate = false; /// TODO: read deduplicate option from table config
const Names deduplicate_by_columns = {};
const bool cleanup = (storage_settings_ptr->clean_deleted_rows != CleanDeletedRows::Never);
CreateMergeEntryResult create_result = CreateMergeEntryResult::Other;
enum class AttemptStatus
{
EntryCreated,
NeedRetry,
Limited,
CannotSelect,
};
auto try_assign_merge = [&]() -> AttemptStatus
{
/// We must select parts for merge under merge_selecting_mutex because other threads
/// (OPTIMIZE queries) can assign new merges.
std::lock_guard merge_selecting_lock(merge_selecting_mutex);
auto zookeeper = getZooKeeperAndAssertNotReadonly();
std::optional<ReplicatedMergeTreeMergePredicate> merge_pred;
/// If many merges is already queued, then will queue only small enough merges.
/// Otherwise merge queue could be filled with only large merges,
/// and in the same time, many small parts could be created and won't be merged.
auto merges_and_mutations_queued = queue.countMergesAndPartMutations();
size_t merges_and_mutations_sum = merges_and_mutations_queued.merges + merges_and_mutations_queued.mutations;
if (!canEnqueueBackgroundTask())
{
LOG_TRACE(log, "Reached memory limit for the background tasks ({}), so won't select new parts to merge or mutate."
"Current background tasks memory usage: {}.",
formatReadableSizeWithBinarySuffix(background_memory_tracker.getSoftLimit()),
formatReadableSizeWithBinarySuffix(background_memory_tracker.get()));
return AttemptStatus::Limited;
}
if (merges_and_mutations_sum >= storage_settings_ptr->max_replicated_merges_in_queue)
{
LOG_TRACE(log, "Number of queued merges ({}) and part mutations ({})"
" is greater than max_replicated_merges_in_queue ({}), so won't select new parts to merge or mutate.",
merges_and_mutations_queued.merges,
merges_and_mutations_queued.mutations,
storage_settings_ptr->max_replicated_merges_in_queue);
return AttemptStatus::Limited;
}
UInt64 max_source_parts_size_for_merge = merger_mutator.getMaxSourcePartsSizeForMerge(
storage_settings_ptr->max_replicated_merges_in_queue, merges_and_mutations_sum);
UInt64 max_source_part_size_for_mutation = merger_mutator.getMaxSourcePartSizeForMutation();
bool merge_with_ttl_allowed = merges_and_mutations_queued.merges_with_ttl < storage_settings_ptr->max_replicated_merges_with_ttl_in_queue &&
getTotalMergesWithTTLInMergeList() < storage_settings_ptr->max_number_of_merges_with_ttl_in_pool;
auto future_merged_part = std::make_shared<FutureMergedMutatedPart>();
if (storage_settings.get()->assign_part_uuids)
future_merged_part->uuid = UUIDHelpers::generateV4();
bool can_assign_merge = max_source_parts_size_for_merge > 0;
PartitionIdsHint partitions_to_merge_in;
if (can_assign_merge)
{
auto lightweight_merge_pred = LocalMergePredicate(queue);
partitions_to_merge_in = merger_mutator.getPartitionsThatMayBeMerged(
max_source_parts_size_for_merge, lightweight_merge_pred, merge_with_ttl_allowed, NO_TRANSACTION_PTR);
if (partitions_to_merge_in.empty())
can_assign_merge = false;
else
merge_pred.emplace(queue.getMergePredicate(zookeeper, partitions_to_merge_in));
}
String out_reason;
if (can_assign_merge &&
merger_mutator.selectPartsToMerge(future_merged_part, false, max_source_parts_size_for_merge, *merge_pred,
merge_with_ttl_allowed, NO_TRANSACTION_PTR, out_reason, &partitions_to_merge_in) == SelectPartsDecision::SELECTED)
{
create_result = createLogEntryToMergeParts(
zookeeper,
future_merged_part->parts,
future_merged_part->name,
future_merged_part->uuid,
future_merged_part->part_format,
deduplicate,
deduplicate_by_columns,
cleanup,
nullptr,
merge_pred->getVersion(),
future_merged_part->merge_type);
if (create_result == CreateMergeEntryResult::Ok)
return AttemptStatus::EntryCreated;
if (create_result == CreateMergeEntryResult::LogUpdated)
return AttemptStatus::NeedRetry;
}
/// If there are many mutations in queue, it may happen, that we cannot enqueue enough merges to merge all new parts
if (max_source_part_size_for_mutation == 0 || merges_and_mutations_queued.mutations >= storage_settings_ptr->max_replicated_mutations_in_queue)
return AttemptStatus::Limited;
if (queue.countMutations() > 0)
{
/// We don't need the list of committing blocks to choose a part to mutate
if (!merge_pred)
merge_pred.emplace(queue.getMergePredicate(zookeeper, PartitionIdsHint{}));
/// Choose a part to mutate.
DataPartsVector data_parts = getDataPartsVectorForInternalUsage();
for (const auto & part : data_parts)
{
if (part->getBytesOnDisk() > max_source_part_size_for_mutation)
continue;
std::optional<std::pair<Int64, int>> desired_mutation_version = merge_pred->getDesiredMutationVersion(part);
if (!desired_mutation_version)
continue;
create_result = createLogEntryToMutatePart(
*part,
future_merged_part->uuid,
desired_mutation_version->first,
desired_mutation_version->second,
merge_pred->getVersion());
if (create_result == CreateMergeEntryResult::Ok)
return AttemptStatus::EntryCreated;
if (create_result == CreateMergeEntryResult::LogUpdated)
return AttemptStatus::NeedRetry;
}
}
return AttemptStatus::CannotSelect;
};
AttemptStatus result = AttemptStatus::CannotSelect;
try
{
result = try_assign_merge();
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
}
Float32 new_sleep_ms = merge_selecting_sleep_ms;
if (result == AttemptStatus::EntryCreated || result == AttemptStatus::NeedRetry)
new_sleep_ms /= storage_settings_ptr->merge_selecting_sleep_slowdown_factor;
else if (result == AttemptStatus::CannotSelect)
new_sleep_ms *= storage_settings_ptr->merge_selecting_sleep_slowdown_factor;
new_sleep_ms *= std::uniform_real_distribution<Float32>(1.f, 1.1f)(thread_local_rng);
merge_selecting_sleep_ms = static_cast<UInt64>(new_sleep_ms);
if (merge_selecting_sleep_ms < storage_settings_ptr->merge_selecting_sleep_ms)
merge_selecting_sleep_ms = storage_settings_ptr->merge_selecting_sleep_ms;
if (merge_selecting_sleep_ms > storage_settings_ptr->max_merge_selecting_sleep_ms)
merge_selecting_sleep_ms = storage_settings_ptr->max_merge_selecting_sleep_ms;
if (result == AttemptStatus::EntryCreated)
merge_selecting_task->schedule();
else
{
LOG_TRACE(log, "Scheduling next merge selecting task after {}ms", merge_selecting_sleep_ms);
merge_selecting_task->scheduleAfter(merge_selecting_sleep_ms);
}
}
void StorageReplicatedMergeTree::mutationsFinalizingTask()
{
bool needs_reschedule = false;
try
{
needs_reschedule = queue.tryFinalizeMutations(getZooKeeperAndAssertNotReadonly());
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
needs_reschedule = true;
}
if (needs_reschedule)
{
mutations_finalizing_task->scheduleAfter(MUTATIONS_FINALIZING_SLEEP_MS);
}
else
{
/// Even if no mutations seems to be done or appeared we are trying to
/// finalize them in background because manual control the launch of
/// this function is error prone. This can lead to mutations that
/// processed all the parts but have is_done=0 state for a long time. Or
/// killed mutations, which are also considered as undone.
mutations_finalizing_task->scheduleAfter(MUTATIONS_FINALIZING_IDLE_SLEEP_MS);
}
}
StorageReplicatedMergeTree::CreateMergeEntryResult StorageReplicatedMergeTree::createLogEntryToMergeParts(
zkutil::ZooKeeperPtr & zookeeper,
const DataPartsVector & parts,
const String & merged_name,
const UUID & merged_part_uuid,
const MergeTreeDataPartFormat & merged_part_format,
bool deduplicate,
const Names & deduplicate_by_columns,
bool cleanup,
ReplicatedMergeTreeLogEntryData * out_log_entry,
int32_t log_version,
MergeType merge_type)
{
Strings exists_paths;
exists_paths.reserve(parts.size());
for (const auto & part : parts)
exists_paths.emplace_back(fs::path(replica_path) / "parts" / part->name);
auto exists_results = zookeeper->exists(exists_paths);
bool all_in_zk = true;
for (size_t i = 0; i < parts.size(); ++i)
{
/// If there is no information about part in ZK, we will not merge it.
if (exists_results[i].error == Coordination::Error::ZNONODE)
{
all_in_zk = false;
const auto & part = parts[i];
if (part->modification_time + MAX_AGE_OF_LOCAL_PART_THAT_WASNT_ADDED_TO_ZOOKEEPER < time(nullptr))
{
LOG_WARNING(log, "Part {} (that was selected for merge) with age {} seconds exists locally but not in ZooKeeper. Won't do merge with that part and will check it.", part->name, (time(nullptr) - part->modification_time));
enqueuePartForCheck(part->name);
}
}
}
if (!all_in_zk)
return CreateMergeEntryResult::MissingPart;
ReplicatedMergeTreeLogEntryData entry;
entry.type = LogEntry::MERGE_PARTS;
entry.source_replica = replica_name;
entry.new_part_name = merged_name;
entry.new_part_uuid = merged_part_uuid;
entry.new_part_format = merged_part_format;
entry.merge_type = merge_type;
entry.deduplicate = deduplicate;
entry.deduplicate_by_columns = deduplicate_by_columns;
entry.cleanup = cleanup;
entry.create_time = time(nullptr);
for (const auto & part : parts)
entry.source_parts.push_back(part->name);
Coordination::Requests ops;
Coordination::Responses responses;
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(zookeeper_path) / "log/log-", entry.toString(),
zkutil::CreateMode::PersistentSequential));
ops.emplace_back(zkutil::makeSetRequest(
fs::path(zookeeper_path) / "log", "", log_version)); /// Check and update version.
Coordination::Error code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZOK)
{
String path_created = dynamic_cast<const Coordination::CreateResponse &>(*responses.front()).path_created;
entry.znode_name = path_created.substr(path_created.find_last_of('/') + 1);
ProfileEvents::increment(ProfileEvents::CreatedLogEntryForMerge);
LOG_TRACE(log, "Created log entry {} for merge {}", path_created, merged_name);
}
else if (code == Coordination::Error::ZBADVERSION)
{
ProfileEvents::increment(ProfileEvents::NotCreatedLogEntryForMerge);
LOG_TRACE(log, "Log entry is not created for merge {} because log was updated", merged_name);
return CreateMergeEntryResult::LogUpdated;
}
else
{
zkutil::KeeperMultiException::check(code, ops, responses);
}
if (out_log_entry)
*out_log_entry = entry;
return CreateMergeEntryResult::Ok;
}
StorageReplicatedMergeTree::CreateMergeEntryResult StorageReplicatedMergeTree::createLogEntryToMutatePart(
const IMergeTreeDataPart & part, const UUID & new_part_uuid, Int64 mutation_version, int32_t alter_version, int32_t log_version)
{
auto zookeeper = getZooKeeper();
/// If there is no information about part in ZK, we will not mutate it.
if (!zookeeper->exists(fs::path(replica_path) / "parts" / part.name))
{
if (part.modification_time + MAX_AGE_OF_LOCAL_PART_THAT_WASNT_ADDED_TO_ZOOKEEPER < time(nullptr))
{
LOG_WARNING(log, "Part {} (that was selected for mutation) with age {} seconds exists locally but not in ZooKeeper."
" Won't mutate that part and will check it.", part.name, (time(nullptr) - part.modification_time));
enqueuePartForCheck(part.name);
}
return CreateMergeEntryResult::MissingPart;
}
MergeTreePartInfo new_part_info = part.info;
new_part_info.mutation = mutation_version;
String new_part_name = part.getNewName(new_part_info);
ReplicatedMergeTreeLogEntryData entry;
entry.type = LogEntry::MUTATE_PART;
entry.source_replica = replica_name;
entry.source_parts.push_back(part.name);
entry.new_part_name = new_part_name;
entry.new_part_uuid = new_part_uuid;
entry.create_time = time(nullptr);
entry.alter_version = alter_version;
Coordination::Requests ops;
Coordination::Responses responses;
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(zookeeper_path) / "log/log-", entry.toString(),
zkutil::CreateMode::PersistentSequential));
ops.emplace_back(zkutil::makeSetRequest(
fs::path(zookeeper_path) / "log", "", log_version)); /// Check and update version.
Coordination::Error code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZBADVERSION)
{
ProfileEvents::increment(ProfileEvents::NotCreatedLogEntryForMutation);
LOG_TRACE(log, "Log entry is not created for mutation {} because log was updated", new_part_name);
return CreateMergeEntryResult::LogUpdated;
}
zkutil::KeeperMultiException::check(code, ops, responses);
ProfileEvents::increment(ProfileEvents::CreatedLogEntryForMutation);
LOG_TRACE(log, "Created log entry for mutation {}", new_part_name);
return CreateMergeEntryResult::Ok;
}
void StorageReplicatedMergeTree::getRemovePartFromZooKeeperOps(const String & part_name, Coordination::Requests & ops, bool has_children)
{
String part_path = fs::path(replica_path) / "parts" / part_name;
if (has_children)
{
ops.emplace_back(zkutil::makeRemoveRequest(fs::path(part_path) / "checksums", -1));
ops.emplace_back(zkutil::makeRemoveRequest(fs::path(part_path) / "columns", -1));
}
ops.emplace_back(zkutil::makeRemoveRequest(part_path, -1));
}
void StorageReplicatedMergeTree::removePartAndEnqueueFetch(const String & part_name, bool storage_init)
{
auto zookeeper = getZooKeeper();
DataPartPtr broken_part;
auto outdate_broken_part = [this, &broken_part]()
{
if (!broken_part)
return;
DataPartsLock lock = lockParts();
if (broken_part->getState() == DataPartState::Active)
removePartsFromWorkingSet(NO_TRANSACTION_RAW, {broken_part}, true, &lock);
broken_part.reset();
cleanup_thread.wakeup();
};
/// We don't know exactly what happened to broken part
/// and we are going to remove all covered log entries.
/// It's quite dangerous, so clone covered parts to detached.
auto broken_part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
auto partition_range = getDataPartsVectorInPartitionForInternalUsage({MergeTreeDataPartState::Active, MergeTreeDataPartState::Outdated},
broken_part_info.partition_id);
Strings detached_parts;
for (const auto & part : partition_range)
{
if (!broken_part_info.contains(part->info))
continue;
if (broken_part_info == part->info)
{
chassert(!broken_part);
chassert(!storage_init);
part->was_removed_as_broken = true;
part->makeCloneInDetached("broken", getInMemoryMetadataPtr(), /*disk_transaction*/ {});
broken_part = part;
}
else
{
part->makeCloneInDetached("covered-by-broken", getInMemoryMetadataPtr(), /*disk_transaction*/ {});
}
detached_parts.push_back(part->name);
}
LOG_WARNING(log, "Detached {} parts covered by broken part {}: {}", detached_parts.size(), part_name, fmt::join(detached_parts, ", "));
ThreadFuzzer::maybeInjectSleep();
ThreadFuzzer::maybeInjectMemoryLimitException();
/// It's possible that queue contains entries covered by part_name.
/// For example, we had GET_PART all_1_42_5 and MUTATE_PART all_1_42_5_63,
/// then all_1_42_5_63 was executed by fetching, but part was written to disk incorrectly.
/// In this case we have to remove it as broken and create GET_PART all_1_42_5_63 to fetch it again,
/// but GET_PART all_1_42_5 may be still in the queue.
/// We should remove all covered entries before creating GET_PART entry, because:
/// 1. In the situation described above, we do not know how to merge/mutate all_1_42_5_63 from all_1_42_5,
/// so GET_PART all_1_42_5 (and all source parts) is useless. The only thing we can do is to fetch all_1_42_5_63.
/// 2. If all_1_42_5_63 is lost, then replication may stuck waiting for all_1_42_5_63 to appear,
/// because we may have some covered parts (more precisely, parts with the same min and max blocks)
queue.removePartProducingOpsInRange(zookeeper, broken_part_info, /* covering_entry= */ {});
ThreadFuzzer::maybeInjectSleep();
ThreadFuzzer::maybeInjectMemoryLimitException();
String part_path = fs::path(replica_path) / "parts" / part_name;
while (true)
{
Coordination::Requests ops;
time_t part_create_time = 0;
Coordination::Stat stat;
bool exists_in_zookeeper = zookeeper->exists(part_path, &stat);
if (exists_in_zookeeper)
{
/// Update version of /is_lost node to avoid race condition with cloneReplica(...).
/// cloneReplica(...) expects that if some entry was executed, then its new_part_name is added to /parts,
/// but we are going to remove it from /parts and add to queue again.
Coordination::Stat is_lost_stat;
String is_lost_value = zookeeper->get(replica_path + "/is_lost", &is_lost_stat);
chassert(is_lost_value == "0");
ops.emplace_back(zkutil::makeSetRequest(replica_path + "/is_lost", is_lost_value, is_lost_stat.version));
part_create_time = stat.ctime / 1000;
getRemovePartFromZooKeeperOps(part_name, ops, stat.numChildren > 0);
}
if (!storage_init)
{
/// We use merge predicate + version check here, because DROP RANGE update log version and we are trying to avoid race with it. We must be sure, that our part
/// was not dropped, otherwise we will have fetch entry, but no virtual part for it (DROP RANGE will remove it). So bad sequence is the following:
/// 1) Create DROP PART in log for broken_part (for example because it's not only broken, but also empty)
/// 1.5) Pull to log and start execution (removePartProducingOpsInRange)
/// 2) Execute this method (create GET PART for broken part)
/// 3) Finish DROP PART execution (remove part from virtual parts)
/// 4) Now we get GET PART for broken part which is absent in virtual parts == bug
///
/// Because of version check this method will never create FETCH if drop part exists
ReplicatedMergeTreeMergePredicate merge_pred = queue.getMergePredicate(zookeeper, PartitionIdsHint{broken_part_info.partition_id});
if (merge_pred.isGoingToBeDropped(broken_part_info))
{
LOG_INFO(log, "Broken part {} is covered by drop range, don't need to fetch it", part_name);
outdate_broken_part();
return;
}
/// Check that our version of log (and queue) is the most fresh. Otherwise don't create new entry fetch entry.
ops.emplace_back(zkutil::makeCheckRequest(fs::path(zookeeper_path) / "log", merge_pred.getVersion()));
}
LogEntryPtr log_entry = std::make_shared<LogEntry>();
log_entry->type = LogEntry::GET_PART;
log_entry->create_time = part_create_time;
log_entry->source_replica = "";
log_entry->new_part_name = part_name;
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(replica_path) / "queue/queue-", log_entry->toString(),
zkutil::CreateMode::PersistentSequential));
Coordination::Responses results;
auto rc = zookeeper->tryMulti(ops, results);
if (rc == Coordination::Error::ZBADVERSION)
{
LOG_TRACE(log, "Log updated, cannot create fetch entry for part {}, will retry.", part_name);
continue;
}
zkutil::KeeperMultiException::check(rc, ops, results);
String path_created = dynamic_cast<const Coordination::CreateResponse &>(*results.back()).path_created;
log_entry->znode_name = path_created.substr(path_created.find_last_of('/') + 1);
LOG_DEBUG(log, "Created entry {} to fetch missing part {}", log_entry->znode_name, part_name);
queue.insert(zookeeper, log_entry);
/// Make the part outdated after creating the log entry.
/// Otherwise, if we failed to create the entry, cleanup thread could remove the part from ZooKeeper (leading to diverged replicas)
outdate_broken_part();
return;
}
}
void StorageReplicatedMergeTree::startBeingLeader()
{
auto zookeeper = getZooKeeper();
if (!getSettings()->replicated_can_become_leader)
{
LOG_INFO(log, "Will not enter leader election because replicated_can_become_leader=0");
return;
}
zkutil::checkNoOldLeaders(log, *zookeeper, fs::path(zookeeper_path) / "leader_election");
LOG_INFO(log, "Became leader");
is_leader = true;
}
void StorageReplicatedMergeTree::stopBeingLeader()
{
if (!is_leader)
{
LOG_TRACE(log, "stopBeingLeader called but we are not a leader already");
return;
}
LOG_INFO(log, "Stopped being leader");
is_leader = false;
}
ConnectionTimeouts StorageReplicatedMergeTree::getFetchPartHTTPTimeouts(ContextPtr local_context)
{
auto timeouts = getHTTPTimeouts(local_context);
auto settings = getSettings();
if (settings->replicated_fetches_http_connection_timeout.changed)
timeouts.connection_timeout = settings->replicated_fetches_http_connection_timeout;
if (settings->replicated_fetches_http_send_timeout.changed)
timeouts.send_timeout = settings->replicated_fetches_http_send_timeout;
if (settings->replicated_fetches_http_receive_timeout.changed)
timeouts.receive_timeout = settings->replicated_fetches_http_receive_timeout;
return timeouts;
}
bool StorageReplicatedMergeTree::checkReplicaHavePart(const String & replica, const String & part_name)
{
auto zookeeper = getZooKeeper();
return zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "parts" / part_name);
}
String StorageReplicatedMergeTree::findReplicaHavingPart(const String & part_name, bool active)
{
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
/// Select replicas in uniformly random order.
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
LOG_TRACE(log, "Candidate replicas: {}", replicas.size());
for (const String & replica : replicas)
{
/// We aren't interested in ourself.
if (replica == replica_name)
continue;
LOG_TRACE(log, "Candidate replica: {}", replica);
if (checkReplicaHavePart(replica, part_name) &&
(!active || zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active")))
return replica;
/// Obviously, replica could become inactive or even vanish after return from this method.
}
return {};
}
void StorageReplicatedMergeTree::addLastSentPart(const MergeTreePartInfo & info)
{
{
std::lock_guard lock(last_sent_parts_mutex);
last_sent_parts.emplace_back(info);
static constexpr size_t LAST_SENT_PARS_WINDOW_SIZE = 1000;
while (last_sent_parts.size() > LAST_SENT_PARS_WINDOW_SIZE)
last_sent_parts.pop_front();
}
last_sent_parts_cv.notify_all();
}
void StorageReplicatedMergeTree::waitForUniquePartsToBeFetchedByOtherReplicas(StorageReplicatedMergeTree::ShutdownDeadline shutdown_deadline_)
{
/// Will be true in case in case of query
if (CurrentThread::isInitialized() && CurrentThread::get().getQueryContext() != nullptr)
{
LOG_TRACE(log, "Will not wait for unique parts to be fetched by other replicas because shutdown called from DROP/DETACH query");
return;
}
if (!shutdown_called.load())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Called waitForUniquePartsToBeFetchedByOtherReplicas before shutdown, it's a bug");
auto settings_ptr = getSettings();
auto wait_ms = settings_ptr->wait_for_unique_parts_send_before_shutdown_ms.totalMilliseconds();
if (wait_ms == 0)
{
LOG_INFO(log, "Will not wait for unique parts to be fetched by other replicas because wait time is zero");
return;
}
if (shutdown_deadline_ <= std::chrono::system_clock::now())
{
LOG_INFO(log, "Will not wait for unique parts to be fetched by other replicas because shutdown_deadline already passed");
return;
}
auto zookeeper = getZooKeeperIfTableShutDown();
auto unique_parts_set = findReplicaUniqueParts(replica_name, zookeeper_path, format_version, zookeeper, log);
if (unique_parts_set.empty())
{
LOG_INFO(log, "Will not wait for unique parts to be fetched because we don't have any unique parts");
return;
}
else
{
LOG_INFO(log, "Will wait for {} unique parts to be fetched", unique_parts_set.size());
}
auto wait_predicate = [&] () -> bool
{
for (auto it = unique_parts_set.begin(); it != unique_parts_set.end();)
{
const auto & part = *it;
bool found = false;
for (const auto & sent_part : last_sent_parts | std::views::reverse)
{
if (sent_part.contains(part))
{
LOG_TRACE(log, "Part {} was fetched by some replica", part.getPartNameForLogs());
found = true;
it = unique_parts_set.erase(it);
break;
}
}
if (!found)
break;
}
return unique_parts_set.empty();
};
std::unique_lock lock(last_sent_parts_mutex);
if (!last_sent_parts_cv.wait_until(lock, shutdown_deadline_, wait_predicate))
LOG_INFO(log, "Failed to wait for unique parts to be fetched in {} ms, {} parts can be left on this replica", wait_ms, unique_parts_set.size());
else
LOG_INFO(log, "Successfully waited all the parts");
}
std::set<MergeTreePartInfo> StorageReplicatedMergeTree::findReplicaUniqueParts(const String & replica_name_, const String & zookeeper_path_, MergeTreeDataFormatVersion format_version_, zkutil::ZooKeeper::Ptr zookeeper_, Poco::Logger * log_)
{
if (!zookeeper_->exists(fs::path(zookeeper_path_) / "replicas" / replica_name_ / "is_active"))
{
LOG_INFO(log_, "Our replica is not active, nobody will try to fetch anything");
return {};
}
Strings replicas = zookeeper_->getChildren(fs::path(zookeeper_path_) / "replicas");
Strings our_parts;
std::vector<ActiveDataPartSet> data_parts_on_replicas;
for (const String & replica : replicas)
{
if (!zookeeper_->exists(fs::path(zookeeper_path_) / "replicas" / replica / "is_active"))
{
LOG_TRACE(log_, "Replica {} is not active, skipping", replica);
continue;
}
Strings parts = zookeeper_->getChildren(fs::path(zookeeper_path_) / "replicas" / replica / "parts");
if (replica == replica_name_)
{
LOG_TRACE(log_, "Our replica parts collected {}", replica);
our_parts = parts;
}
else
{
LOG_TRACE(log_, "Fetching parts for replica {}: [{}]", replica, fmt::join(parts, ", "));
data_parts_on_replicas.emplace_back(format_version_, parts);
}
}
if (data_parts_on_replicas.empty())
{
LOG_TRACE(log_, "Has no active replicas, will no try to wait for fetch");
return {};
}
std::set<MergeTreePartInfo> our_unique_parts;
for (const auto & part : our_parts)
{
bool found = false;
for (const auto & active_parts_set : data_parts_on_replicas)
{
if (!active_parts_set.getContainingPart(part).empty())
{
found = true;
break;
}
}
if (!found)
{
LOG_TRACE(log_, "Part not {} found on other replicas", part);
our_unique_parts.emplace(MergeTreePartInfo::fromPartName(part, format_version_));
}
}
if (!our_parts.empty() && our_unique_parts.empty())
LOG_TRACE(log_, "All parts found on replicas");
return our_unique_parts;
}
String StorageReplicatedMergeTree::findReplicaHavingCoveringPart(LogEntry & entry, bool active)
{
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
/// Select replicas in uniformly random order.
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
for (const String & replica : replicas)
{
if (replica == replica_name)
continue;
if (active && !zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active"))
continue;
String largest_part_found;
Strings parts = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas" / replica / "parts");
for (const String & part_on_replica : parts)
{
if (part_on_replica == entry.new_part_name
|| MergeTreePartInfo::contains(part_on_replica, entry.new_part_name, format_version))
{
if (largest_part_found.empty()
|| MergeTreePartInfo::contains(part_on_replica, largest_part_found, format_version))
{
largest_part_found = part_on_replica;
}
}
}
if (!largest_part_found.empty())
{
bool the_same_part = largest_part_found == entry.new_part_name;
/// Make a check in case if selected part differs from source part
if (!the_same_part)
{
String reject_reason;
if (!queue.addFuturePartIfNotCoveredByThem(largest_part_found, entry, reject_reason))
{
LOG_INFO(log, "Will not fetch part {} covering {}. {}", largest_part_found, entry.new_part_name, reject_reason);
return {};
}
}
return replica;
}
}
return {};
}
String StorageReplicatedMergeTree::findReplicaHavingCoveringPart(
const String & part_name, bool active, String & found_part_name)
{
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
/// Select replicas in uniformly random order.
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
String largest_part_found;
String largest_replica_found;
for (const String & replica : replicas)
{
if (replica == replica_name)
continue;
if (active && !zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active"))
continue;
Strings parts = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas" / replica / "parts");
for (const String & part_on_replica : parts)
{
if (part_on_replica == part_name
|| MergeTreePartInfo::contains(part_on_replica, part_name, format_version))
{
if (largest_part_found.empty()
|| MergeTreePartInfo::contains(part_on_replica, largest_part_found, format_version))
{
largest_part_found = part_on_replica;
largest_replica_found = replica;
}
}
}
}
found_part_name = largest_part_found;
return largest_replica_found;
}
/** If a quorum is tracked for a part, update information about it in ZK.
*/
void StorageReplicatedMergeTree::updateQuorum(const String & part_name, bool is_parallel)
{
if (is_parallel && format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Parallel quorum inserts are not compatible with the deprecated syntax of *MergeTree engines");
auto zookeeper = getZooKeeper();
/// Information on which replicas a part has been added, if the quorum has not yet been reached.
String quorum_status_path = fs::path(zookeeper_path) / "quorum" / "status";
if (is_parallel)
quorum_status_path = fs::path(zookeeper_path) / "quorum" / "parallel" / part_name;
/// The name of the previous part for which the quorum was reached.
const String quorum_last_part_path = fs::path(zookeeper_path) / "quorum" / "last_part";
String value;
Coordination::Stat stat;
/// If there is no node, then all quorum INSERTs have already reached the quorum, and nothing is needed.
while (zookeeper->tryGet(quorum_status_path, value, &stat))
{
ReplicatedMergeTreeQuorumEntry quorum_entry(value);
if (quorum_entry.part_name != part_name)
{
LOG_TRACE(log, "Quorum {}, already achieved for part {} current part {}",
quorum_status_path, part_name, quorum_entry.part_name);
/// The quorum has already been achieved. Moreover, another INSERT with a quorum has already started.
break;
}
quorum_entry.replicas.insert(replica_name);
if (quorum_entry.replicas.size() >= quorum_entry.required_number_of_replicas)
{
/// The quorum is reached. Delete the node, and update information about the last part that was successfully written with quorum.
LOG_TRACE(log, "Got {} (of {} required) replicas confirmed quorum {}, going to remove node",
quorum_entry.replicas.size(), quorum_entry.required_number_of_replicas, quorum_status_path);
Coordination::Requests ops;
Coordination::Responses responses;
if (!is_parallel)
{
Coordination::Stat added_parts_stat;
String old_added_parts = zookeeper->get(quorum_last_part_path, &added_parts_stat);
ReplicatedMergeTreeQuorumAddedParts parts_with_quorum(format_version);
if (!old_added_parts.empty())
parts_with_quorum.fromString(old_added_parts);
auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
/// We store one last part which reached quorum for each partition.
parts_with_quorum.added_parts[part_info.partition_id] = part_name;
String new_added_parts = parts_with_quorum.toString();
ops.emplace_back(zkutil::makeRemoveRequest(quorum_status_path, stat.version));
ops.emplace_back(zkutil::makeSetRequest(quorum_last_part_path, new_added_parts, added_parts_stat.version));
}
else
ops.emplace_back(zkutil::makeRemoveRequest(quorum_status_path, stat.version));
auto code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::Error::ZOK)
{
break;
}
else if (code == Coordination::Error::ZNONODE)
{
/// The quorum has already been achieved.
break;
}
else if (code == Coordination::Error::ZBADVERSION)
{
/// Node was updated meanwhile. We must re-read it and repeat all the actions.
continue;
}
else
throw Coordination::Exception::fromPath(code, quorum_status_path);
}
else
{
LOG_TRACE(log, "Quorum {} still not satisfied (have only {} of {} replicas), updating node",
quorum_status_path, quorum_entry.replicas.size(), quorum_entry.required_number_of_replicas);
/// We update the node, registering there one more replica.
auto code = zookeeper->trySet(quorum_status_path, quorum_entry.toString(), stat.version);
if (code == Coordination::Error::ZOK)
{
break;
}
else if (code == Coordination::Error::ZNONODE)
{
/// The quorum has already been achieved.
break;
}
else if (code == Coordination::Error::ZBADVERSION)
{
/// Node was updated meanwhile. We must re-read it and repeat all the actions.
continue;
}
else
throw Coordination::Exception::fromPath(code, quorum_status_path);
}
}
}
void StorageReplicatedMergeTree::cleanLastPartNode(const String & partition_id)
{
auto zookeeper = getZooKeeper();
LOG_DEBUG(log, "Cleaning up last part node for partition {}", partition_id);
/// The name of the previous part for which the quorum was reached.
const String quorum_last_part_path = fs::path(zookeeper_path) / "quorum" / "last_part";
/// Delete information from "last_part" node.
while (true)
{
Coordination::Stat added_parts_stat;
String old_added_parts = zookeeper->get(quorum_last_part_path, &added_parts_stat);
ReplicatedMergeTreeQuorumAddedParts parts_with_quorum(format_version);
if (!old_added_parts.empty())
parts_with_quorum.fromString(old_added_parts);
/// Delete information about particular partition.
if (!parts_with_quorum.added_parts.contains(partition_id))
{
/// There is no information about interested part.
LOG_TEST(log, "There is no information about the partition");
break;
}
parts_with_quorum.added_parts.erase(partition_id);
String new_added_parts = parts_with_quorum.toString();
auto code = zookeeper->trySet(quorum_last_part_path, new_added_parts, added_parts_stat.version);
if (code == Coordination::Error::ZOK)
{
LOG_DEBUG(log, "Last parent node for partition {} is cleaned up", partition_id);
break;
}
else if (code == Coordination::Error::ZNONODE)
{
/// Node is deleted. It is impossible, but it is Ok.
LOG_WARNING(log, "The last part node {} was deleted", quorum_last_part_path);
break;
}
else if (code == Coordination::Error::ZBADVERSION)
{
/// Node was updated meanwhile. We must re-read it and repeat all the actions.
continue;
}
else
throw Coordination::Exception::fromPath(code, quorum_last_part_path);
}
}
bool StorageReplicatedMergeTree::partIsInsertingWithParallelQuorum(const MergeTreePartInfo & part_info) const
{
auto zookeeper = getZooKeeper();
return zookeeper->exists(fs::path(zookeeper_path) / "quorum" / "parallel" / part_info.getPartNameV1());
}
bool StorageReplicatedMergeTree::partIsLastQuorumPart(const MergeTreePartInfo & part_info) const
{
auto zookeeper = getZooKeeper();
const String parts_with_quorum_path = fs::path(zookeeper_path) / "quorum" / "last_part";
String parts_with_quorum_str = zookeeper->get(parts_with_quorum_path);
if (parts_with_quorum_str.empty())
return false;
ReplicatedMergeTreeQuorumAddedParts parts_with_quorum(format_version);
parts_with_quorum.fromString(parts_with_quorum_str);
auto partition_it = parts_with_quorum.added_parts.find(part_info.partition_id);
if (partition_it == parts_with_quorum.added_parts.end())
return false;
return partition_it->second == part_info.getPartNameAndCheckFormat(format_version);
}
bool StorageReplicatedMergeTree::fetchPart(
const String & part_name,
const StorageMetadataPtr & metadata_snapshot,
const String & source_zookeeper_name,
const String & source_replica_path,
bool to_detached,
size_t quorum,
zkutil::ZooKeeper::Ptr zookeeper_,
bool try_fetch_shared)
{
auto zookeeper = zookeeper_ ? zookeeper_ : getZooKeeper();
const auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
if (!to_detached)
{
if (auto part = getPartIfExists(part_info, {MergeTreeDataPartState::Outdated, MergeTreeDataPartState::Deleting}))
{
LOG_DEBUG(log, "Part {} should be deleted after previous attempt before fetch", part->name);
/// Force immediate parts cleanup to delete the part that was left from the previous fetch attempt.
cleanup_thread.wakeup();
return false;
}
}
{
std::lock_guard lock(currently_fetching_parts_mutex);
if (!currently_fetching_parts.insert(part_name).second)
{
LOG_DEBUG(log, "Part {} is already fetching right now", part_name);
return false;
}
}
SCOPE_EXIT_MEMORY
({
std::lock_guard lock(currently_fetching_parts_mutex);
currently_fetching_parts.erase(part_name);
});
LOG_DEBUG(log, "Fetching part {} from {}:{}", part_name, source_zookeeper_name, source_replica_path);
auto settings_ptr = getSettings();
TableLockHolder table_lock_holder;
if (!to_detached)
table_lock_holder = lockForShare(RWLockImpl::NO_QUERY, settings_ptr->lock_acquire_timeout_for_background_operations);
/// Logging
Stopwatch stopwatch;
MutableDataPartPtr part;
DataPartsVector replaced_parts;
ProfileEventsScope profile_events_scope;
auto write_part_log = [&] (const ExecutionStatus & execution_status)
{
writePartLog(
PartLogElement::DOWNLOAD_PART, execution_status, stopwatch.elapsed(),
part_name, part, replaced_parts, nullptr,
profile_events_scope.getSnapshot());
};
auto is_zero_copy_part = [&settings_ptr](const auto & data_part)
{
return settings_ptr->allow_remote_fs_zero_copy_replication && data_part->isStoredOnRemoteDiskWithZeroCopySupport();
};
DataPartPtr part_to_clone;
{
/// If the desired part is a result of a part mutation, try to find the source part and compare
/// its checksums to the checksums of the desired part. If they match, we can just clone the local part.
/// If we have the source part, its part_info will contain covered_part_info.
auto covered_part_info = part_info;
covered_part_info.mutation = 0;
auto source_part = getActiveContainingPart(covered_part_info);
/// Fetch for zero-copy replication is cheap and straightforward, so we don't use local clone here
if (source_part && !is_zero_copy_part(source_part))
{
auto source_part_header = ReplicatedMergeTreePartHeader::fromColumnsAndChecksums(
source_part->getColumns(), source_part->checksums);
String part_path = fs::path(source_replica_path) / "parts" / part_name;
String part_znode = zookeeper->get(part_path);
std::optional<ReplicatedMergeTreePartHeader> desired_part_header;
if (!part_znode.empty())
{
desired_part_header = ReplicatedMergeTreePartHeader::fromString(part_znode);
}
else
{
String columns_str;
String checksums_str;
if (zookeeper->tryGet(fs::path(part_path) / "columns", columns_str) &&
zookeeper->tryGet(fs::path(part_path) / "checksums", checksums_str))
{
desired_part_header = ReplicatedMergeTreePartHeader::fromColumnsAndChecksumsZNodes(columns_str, checksums_str);
}
else
{
LOG_INFO(log, "Not checking checksums of part {} with replica {}:{} because part was removed from ZooKeeper",
part_name, source_zookeeper_name, source_replica_path);
}
}
/// Checking both checksums and columns hash. For example we can have empty part
/// with same checksums but different columns. And we attaching it exception will
/// be thrown.
if (desired_part_header
&& source_part_header.getColumnsHash() == desired_part_header->getColumnsHash()
&& source_part_header.getChecksums() == desired_part_header->getChecksums())
{
LOG_TRACE(log, "Found local part {} with the same checksums and columns hash as {}", source_part->name, part_name);
part_to_clone = source_part;
}
}
}
ReplicatedMergeTreeAddress address;
ConnectionTimeouts timeouts;
String interserver_scheme;
InterserverCredentialsPtr credentials;
std::optional<CurrentlySubmergingEmergingTagger> tagger_ptr;
std::function<MutableDataPartPtr()> get_part;
scope_guard part_directory_lock;
if (part_to_clone)
{
get_part = [&, part_to_clone]()
{
chassert(!is_zero_copy_part(part_to_clone));
IDataPartStorage::ClonePartParams clone_params{ .keep_metadata_version = true };
auto [cloned_part, lock] = cloneAndLoadDataPartOnSameDisk(part_to_clone, "tmp_clone_", part_info, metadata_snapshot, clone_params);
part_directory_lock = std::move(lock);
return cloned_part;
};
}
else
{
address.fromString(zookeeper->get(fs::path(source_replica_path) / "host"));
timeouts = getFetchPartHTTPTimeouts(getContext());
credentials = getContext()->getInterserverCredentials();
interserver_scheme = getContext()->getInterserverScheme();
get_part = [&, address, timeouts, credentials, interserver_scheme]()
{
if (interserver_scheme != address.scheme)
throw Exception(ErrorCodes::INTERSERVER_SCHEME_DOESNT_MATCH, "Interserver schemes are different: "
"'{}' != '{}', can't fetch part from {}", interserver_scheme, address.scheme, address.host);
auto [fetched_part, lock] = fetcher.fetchSelectedPart(
metadata_snapshot,
getContext(),
part_name,
source_zookeeper_name,
source_replica_path,
address.host,
address.replication_port,
timeouts,
credentials->getUser(),
credentials->getPassword(),
interserver_scheme,
replicated_fetches_throttler,
to_detached,
"",
&tagger_ptr,
try_fetch_shared);
part_directory_lock = std::move(lock);
return fetched_part;
};
}
try
{
part = get_part();
if (!to_detached)
{
Transaction transaction(*this, NO_TRANSACTION_RAW);
renameTempPartAndReplace(part, transaction);
chassert(!part_to_clone || !is_zero_copy_part(part));
replaced_parts = checkPartChecksumsAndCommit(transaction, part, /*hardlinked_files*/ {}, /*replace_zero_copy_lock*/ true);
/** If a quorum is tracked for this part, you must update it.
* If you do not have time, in case of losing the session, when you restart the server - see the `ReplicatedMergeTreeRestartingThread::updateQuorumIfWeHavePart` method.
*/
if (quorum)
{
/// Check if this quorum insert is parallel or not
if (zookeeper->exists(fs::path(zookeeper_path) / "quorum" / "parallel" / part_name))
updateQuorum(part_name, true);
else if (zookeeper->exists(fs::path(zookeeper_path) / "quorum" / "status"))
updateQuorum(part_name, false);
}
/// merged parts that are still inserted with quorum. if it only contains one block, it hasn't been merged before
if (part_info.level != 0 || part_info.mutation != 0)
{
Strings quorum_parts = zookeeper->getChildren(fs::path(zookeeper_path) / "quorum" / "parallel");
for (const String & quorum_part : quorum_parts)
{
auto quorum_part_info = MergeTreePartInfo::fromPartName(quorum_part, format_version);
if (part_info.contains(quorum_part_info))
updateQuorum(quorum_part, true);
}
}
merge_selecting_task->schedule();
for (const auto & replaced_part : replaced_parts)
{
LOG_DEBUG(log, "Part {} is rendered obsolete by fetching part {}", replaced_part->name, part_name);
ProfileEvents::increment(ProfileEvents::ObsoleteReplicatedParts);
}
write_part_log({});
}
else
{
// The fetched part is valuable and should not be cleaned like a temp part.
part->is_temp = false;
part->renameTo(fs::path("detached") / part_name, true);
}
}
catch (const Exception & e)
{
/// The same part is being written right now (but probably it's not committed yet).
/// We will check the need for fetch later.
if (e.code() == ErrorCodes::DIRECTORY_ALREADY_EXISTS)
{
LOG_TRACE(log, "Not fetching part: {}", e.message());
return false;
}
throw;
}
catch (...)
{
if (!to_detached)
write_part_log(ExecutionStatus::fromCurrentException("", true));
throw;
}
ProfileEvents::increment(ProfileEvents::ReplicatedPartFetches);
if (part_to_clone)
LOG_DEBUG(log, "Cloned part {} from {}{}", part_name, part_to_clone->name, to_detached ? " (to 'detached' directory)" : "");
else
LOG_DEBUG(log, "Fetched part {} from {}:{}{}", part_name, source_zookeeper_name, source_replica_path, to_detached ? " (to 'detached' directory)" : "");
return true;
}
MergeTreeData::MutableDataPartPtr StorageReplicatedMergeTree::fetchExistsPart(
const String & part_name,
const StorageMetadataPtr & metadata_snapshot,
const String & source_replica_path,
DiskPtr replaced_disk,
String replaced_part_path)
{
auto zookeeper = getZooKeeper();
const auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
if (auto part = getPartIfExists(part_info, {MergeTreeDataPartState::Outdated, MergeTreeDataPartState::Deleting}))
{
LOG_DEBUG(log, "Part {} should be deleted after previous attempt before fetch", part->name);
/// Force immediate parts cleanup to delete the part that was left from the previous fetch attempt.
cleanup_thread.wakeup();
return nullptr;
}
{
std::lock_guard lock(currently_fetching_parts_mutex);
if (!currently_fetching_parts.insert(part_name).second)
{
LOG_DEBUG(log, "Part {} is already fetching right now", part_name);
return nullptr;
}
}
SCOPE_EXIT_MEMORY
({
std::lock_guard lock(currently_fetching_parts_mutex);
currently_fetching_parts.erase(part_name);
});
LOG_DEBUG(log, "Fetching already known part {} from {}:{}", part_name, zookeeper_name, source_replica_path);
TableLockHolder table_lock_holder = lockForShare(RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
/// Logging
Stopwatch stopwatch;
MutableDataPartPtr part;
DataPartsVector replaced_parts;
ProfileEventsScope profile_events_scope;
auto write_part_log = [&] (const ExecutionStatus & execution_status)
{
writePartLog(
PartLogElement::DOWNLOAD_PART, execution_status, stopwatch.elapsed(),
part_name, part, replaced_parts, nullptr,
profile_events_scope.getSnapshot());
};
std::function<MutableDataPartPtr()> get_part;
ReplicatedMergeTreeAddress address(zookeeper->get(fs::path(source_replica_path) / "host"));
auto timeouts = getHTTPTimeouts(getContext());
auto credentials = getContext()->getInterserverCredentials();
String interserver_scheme = getContext()->getInterserverScheme();
scope_guard part_temp_directory_lock;
get_part = [&, address, timeouts, interserver_scheme, credentials]()
{
if (interserver_scheme != address.scheme)
throw Exception(ErrorCodes::INTERSERVER_SCHEME_DOESNT_MATCH, "Interserver schemes are different: "
"'{}' != '{}', can't fetch part from {}", interserver_scheme, address.scheme, address.host);
auto [fetched_part, lock] = fetcher.fetchSelectedPart(
metadata_snapshot, getContext(), part_name, zookeeper_name, source_replica_path,
address.host, address.replication_port,
timeouts, credentials->getUser(), credentials->getPassword(),
interserver_scheme, replicated_fetches_throttler, false, "", nullptr, true,
replaced_disk);
part_temp_directory_lock = std::move(lock);
return fetched_part;
};
try
{
part = get_part();
if (part->getDataPartStorage().getDiskName() != replaced_disk->getName())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Part {} fetched on wrong disk {}", part->name, part->getDataPartStorage().getDiskName());
auto replaced_path = fs::path(replaced_part_path);
part->getDataPartStorage().rename(replaced_path.parent_path(), replaced_path.filename(), nullptr, true, false);
}
catch (const Exception & e)
{
/// The same part is being written right now (but probably it's not committed yet).
/// We will check the need for fetch later.
if (e.code() == ErrorCodes::DIRECTORY_ALREADY_EXISTS)
{
LOG_TRACE(log, "Not fetching part: {}", e.message());
return nullptr;
}
throw;
}
catch (...)
{
write_part_log(ExecutionStatus::fromCurrentException("", true));
throw;
}
ProfileEvents::increment(ProfileEvents::ReplicatedPartFetches);
LOG_DEBUG(log, "Fetched part {} from {}:{}", part_name, zookeeper_name, source_replica_path);
return part;
}
void StorageReplicatedMergeTree::startup()
{
LOG_TRACE(log, "Starting up table");
startOutdatedDataPartsLoadingTask();
if (attach_thread)
{
attach_thread->start();
attach_thread->waitFirstTry();
return;
}
startupImpl(/* from_attach_thread */ false);
}
void StorageReplicatedMergeTree::startupImpl(bool from_attach_thread)
{
/// Do not start replication if ZooKeeper is not configured or there is no metadata in zookeeper
if (!has_metadata_in_zookeeper.has_value() || !*has_metadata_in_zookeeper)
{
if (!since_metadata_err_incr_readonly_metric)
{
since_metadata_err_incr_readonly_metric = true;
CurrentMetrics::add(CurrentMetrics::ReadonlyReplica);
}
LOG_TRACE(log, "No connection to ZooKeeper or no metadata in ZooKeeper, will not startup");
return;
}
if (since_metadata_err_incr_readonly_metric)
{
since_metadata_err_incr_readonly_metric = false;
CurrentMetrics::sub(CurrentMetrics::ReadonlyReplica);
assert(CurrentMetrics::get(CurrentMetrics::ReadonlyReplica) >= 0);
}
try
{
auto zookeeper = getZooKeeper();
InterserverIOEndpointPtr data_parts_exchange_ptr = std::make_shared<DataPartsExchange::Service>(*this);
[[maybe_unused]] auto prev_ptr = std::atomic_exchange(&data_parts_exchange_endpoint, data_parts_exchange_ptr);
assert(prev_ptr == nullptr);
/// The endpoint id:
/// old format: DataPartsExchange:/clickhouse/tables/default/t1/{shard}/{replica}
/// new format: DataPartsExchange:{zookeeper_name}:/clickhouse/tables/default/t1/{shard}/{replica}
/// Notice:
/// They are incompatible and the default is the old format.
/// If you want to use the new format, please ensure that 'enable_the_endpoint_id_with_zookeeper_name_prefix' of all nodes is true .
///
getContext()->getInterserverIOHandler().addEndpoint(
data_parts_exchange_ptr->getId(getEndpointName()), data_parts_exchange_ptr);
startBeingLeader();
/// Activate replica in a separate thread if we are not calling from attach thread
restarting_thread.start(/*schedule=*/!from_attach_thread);
if (from_attach_thread)
{
LOG_TRACE(log, "Trying to startup table from right now");
/// Try activating replica in current thread.
restarting_thread.run();
}
else
{
/// Wait while restarting_thread finishing initialization.
/// NOTE It does not mean that replication is actually started after receiving this event.
/// It only means that an attempt to startup replication was made.
/// Table may be still in readonly mode if this attempt failed for any reason.
while (!startup_event.tryWait(10 * 1000))
LOG_TRACE(log, "Waiting for RestartingThread to startup table");
}
auto lock = std::unique_lock<std::mutex>(flush_and_shutdown_mutex, std::defer_lock);
do
{
if (shutdown_prepared_called.load() || shutdown_called.load())
throw Exception(ErrorCodes::TABLE_IS_DROPPED, "Cannot startup table because it is dropped");
}
while (!lock.try_lock());
/// And this is just a callback
session_expired_callback_handler = EventNotifier::instance().subscribe(Coordination::Error::ZSESSIONEXPIRED, [this]()
{
LOG_TEST(log, "Received event for expired session. Waking up restarting thread");
restarting_thread.start();
});
startBackgroundMovesIfNeeded();
part_moves_between_shards_orchestrator.start();
}
catch (...)
{
/// Exception safety: failed "startup" does not require a call to "shutdown" from the caller.
/// And it should be able to safely destroy table after exception in "startup" method.
/// It means that failed "startup" must not create any background tasks that we will have to wait.
try
{
/// it's important to avoid full shutdown here, because it even tries to shutdown attach thread which was
/// designed exactly for this: try to start table if no zookeeper connection available.
if (from_attach_thread)
{
restarting_thread.shutdown(/* part_of_full_shutdown */false);
}
else
{
shutdown();
}
}
catch (...)
{
std::terminate();
}
/// Note: after failed "startup", the table will be in a state that only allows to destroy the object.
throw;
}
}
void StorageReplicatedMergeTree::flushAndPrepareForShutdown()
{
std::lock_guard lock{flush_and_shutdown_mutex};
if (shutdown_prepared_called.exchange(true))
return;
try
{
auto settings_ptr = getSettings();
/// Cancel fetches, merges and mutations to force the queue_task to finish ASAP.
fetcher.blocker.cancelForever();
merger_mutator.merges_blocker.cancelForever();
parts_mover.moves_blocker.cancelForever();
stopBeingLeader();
if (attach_thread)
attach_thread->shutdown();
restarting_thread.shutdown(/* part_of_full_shutdown */true);
/// Explicitly set the event, because the restarting thread will not set it again
startup_event.set();
shutdown_deadline.emplace(std::chrono::system_clock::now() + std::chrono::milliseconds(settings_ptr->wait_for_unique_parts_send_before_shutdown_ms.totalMilliseconds()));
}
catch (...)
{
/// Don't wait anything in case of improper prepare for shutdown
shutdown_deadline.emplace(std::chrono::system_clock::now());
throw;
}
}
void StorageReplicatedMergeTree::partialShutdown()
{
ProfileEvents::increment(ProfileEvents::ReplicaPartialShutdown);
partial_shutdown_called = true;
partial_shutdown_event.set();
queue.notifySubscribersOnPartialShutdown();
replica_is_active_node = nullptr;
LOG_TRACE(log, "Waiting for threads to finish");
merge_selecting_task->deactivate();
queue_updating_task->deactivate();
mutations_updating_task->deactivate();
mutations_finalizing_task->deactivate();
cleanup_thread.stop();
async_block_ids_cache.stop();
part_check_thread.stop();
/// Stop queue processing
{
auto fetch_lock = fetcher.blocker.cancel();
auto merge_lock = merger_mutator.merges_blocker.cancel();
auto move_lock = parts_mover.moves_blocker.cancel();
background_operations_assignee.finish();
}
LOG_TRACE(log, "Threads finished");
}
void StorageReplicatedMergeTree::shutdown()
{
if (shutdown_called.exchange(true))
return;
flushAndPrepareForShutdown();
if (!shutdown_deadline.has_value())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Shutdown deadline is not set in shutdown");
try
{
waitForUniquePartsToBeFetchedByOtherReplicas(*shutdown_deadline);
}
catch (const Exception & ex)
{
if (ex.code() == ErrorCodes::LOGICAL_ERROR)
throw;
tryLogCurrentException(log, __PRETTY_FUNCTION__);
}
session_expired_callback_handler.reset();
stopOutdatedDataPartsLoadingTask();
partialShutdown();
part_moves_between_shards_orchestrator.shutdown();
{
auto lock = queue.lockQueue();
/// Cancel logs pulling after background task were cancelled. It's still
/// required because we can trigger pullLogsToQueue during manual OPTIMIZE,
/// MUTATE, etc. query.
queue.pull_log_blocker.cancelForever();
}
background_moves_assignee.finish();
auto data_parts_exchange_ptr = std::atomic_exchange(&data_parts_exchange_endpoint, InterserverIOEndpointPtr{});
if (data_parts_exchange_ptr)
{
getContext()->getInterserverIOHandler().removeEndpointIfExists(data_parts_exchange_ptr->getId(getEndpointName()));
/// Ask all parts exchange handlers to finish asap. New ones will fail to start
data_parts_exchange_ptr->blocker.cancelForever();
/// Wait for all of them
std::lock_guard lock(data_parts_exchange_ptr->rwlock);
}
}
StorageReplicatedMergeTree::~StorageReplicatedMergeTree()
{
try
{
shutdown();
}
catch (...)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
}
}
ReplicatedMergeTreeQuorumAddedParts::PartitionIdToMaxBlock StorageReplicatedMergeTree::getMaxAddedBlocks() const
{
ReplicatedMergeTreeQuorumAddedParts::PartitionIdToMaxBlock max_added_blocks;
for (const auto & data_part : getDataPartsForInternalUsage())
{
max_added_blocks[data_part->info.partition_id]
= std::max(max_added_blocks[data_part->info.partition_id], data_part->info.max_block);
}
auto zookeeper = getZooKeeper();
const String quorum_status_path = fs::path(zookeeper_path) / "quorum" / "status";
String value;
Coordination::Stat stat;
if (zookeeper->tryGet(quorum_status_path, value, &stat))
{
ReplicatedMergeTreeQuorumEntry quorum_entry;
quorum_entry.fromString(value);
auto part_info = MergeTreePartInfo::fromPartName(quorum_entry.part_name, format_version);
max_added_blocks[part_info.partition_id] = part_info.max_block - 1;
}
String added_parts_str;
if (zookeeper->tryGet(fs::path(zookeeper_path) / "quorum" / "last_part", added_parts_str))
{
if (!added_parts_str.empty())
{
ReplicatedMergeTreeQuorumAddedParts part_with_quorum(format_version);
part_with_quorum.fromString(added_parts_str);
auto added_parts = part_with_quorum.added_parts;
for (const auto & added_part : added_parts)
{
if (!getActiveContainingPart(added_part.second))
throw Exception(ErrorCodes::REPLICA_IS_NOT_IN_QUORUM,
"Replica doesn't have part '{}' which was successfully written to quorum of other replicas. "
"Send query to another replica or disable 'select_sequential_consistency' setting", added_part.second);
}
for (const auto & max_block : part_with_quorum.getMaxInsertedBlocks())
max_added_blocks[max_block.first] = max_block.second;
}
}
return max_added_blocks;
}
void StorageReplicatedMergeTree::read(
QueryPlan & query_plan,
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
const size_t max_block_size,
const size_t num_streams)
{
const auto & settings = local_context->getSettingsRef();
/// The `select_sequential_consistency` setting has two meanings:
/// 1. To throw an exception if on a replica there are not all parts which have been written down on quorum of remaining replicas.
/// 2. Do not read parts that have not yet been written to the quorum of the replicas.
/// For this you have to synchronously go to ZooKeeper.
if (settings.select_sequential_consistency)
return readLocalSequentialConsistencyImpl(query_plan, column_names, storage_snapshot, query_info, local_context, processed_stage, max_block_size, num_streams);
if (local_context->canUseParallelReplicasOnInitiator())
return readParallelReplicasImpl(query_plan, column_names, storage_snapshot, query_info, local_context, processed_stage, max_block_size, num_streams);
readLocalImpl(query_plan, column_names, storage_snapshot, query_info, local_context, processed_stage, max_block_size, num_streams);
}
void StorageReplicatedMergeTree::readLocalSequentialConsistencyImpl(
QueryPlan & query_plan,
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
size_t max_block_size,
size_t num_streams)
{
auto max_added_blocks = std::make_shared<ReplicatedMergeTreeQuorumAddedParts::PartitionIdToMaxBlock>(getMaxAddedBlocks());
auto plan = reader.read(column_names, storage_snapshot, query_info, local_context,
max_block_size, num_streams, processed_stage, std::move(max_added_blocks),
/* enable_parallel_reading= */false);
if (plan)
query_plan = std::move(*plan);
}
void StorageReplicatedMergeTree::readParallelReplicasImpl(
QueryPlan & query_plan,
const Names & /*column_names*/,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
const size_t /*max_block_size*/,
const size_t /*num_streams*/)
{
auto table_id = getStorageID();
auto scalars = local_context->hasQueryContext() ? local_context->getQueryContext()->getScalars() : Scalars{};
String cluster_for_parallel_replicas = local_context->getSettingsRef().cluster_for_parallel_replicas;
auto parallel_replicas_cluster = local_context->getCluster(cluster_for_parallel_replicas);
ASTPtr modified_query_ast;
Block header;
if (local_context->getSettingsRef().allow_experimental_analyzer)
{
auto modified_query_tree = buildQueryTreeForShard(query_info, query_info.query_tree);
header = InterpreterSelectQueryAnalyzer::getSampleBlock(
modified_query_tree, local_context, SelectQueryOptions(processed_stage).analyze());
modified_query_ast = queryNodeToSelectQuery(modified_query_tree);
}
else
{
modified_query_ast = ClusterProxy::rewriteSelectQuery(local_context, query_info.query,
table_id.database_name, table_id.table_name, /*remote_table_function_ptr*/nullptr);
header
= InterpreterSelectQuery(modified_query_ast, local_context, SelectQueryOptions(processed_stage).analyze()).getSampleBlock();
}
ClusterProxy::SelectStreamFactory select_stream_factory = ClusterProxy::SelectStreamFactory(
header,
{},
storage_snapshot,
processed_stage);
ClusterProxy::executeQueryWithParallelReplicas(
query_plan, getStorageID(),
/* table_func_ptr= */ nullptr,
select_stream_factory, modified_query_ast,
local_context, query_info, parallel_replicas_cluster);
}
void StorageReplicatedMergeTree::readLocalImpl(
QueryPlan & query_plan,
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
const size_t max_block_size,
const size_t num_streams)
{
auto plan = reader.read(
column_names, storage_snapshot, query_info,
local_context, max_block_size, num_streams,
processed_stage,
/* max_block_numbers_to_read= */ nullptr,
/* enable_parallel_reading= */ local_context->canUseParallelReplicasOnFollower());
if (plan)
query_plan = std::move(*plan);
}
template <class Func>
void StorageReplicatedMergeTree::foreachActiveParts(Func && func, bool select_sequential_consistency) const
{
std::optional<ReplicatedMergeTreeQuorumAddedParts::PartitionIdToMaxBlock> max_added_blocks = {};
/**
* Synchronously go to ZooKeeper when select_sequential_consistency enabled
*/
if (select_sequential_consistency)
max_added_blocks = getMaxAddedBlocks();
auto lock = lockParts();
/// TODO Transactions: should we count visible parts only?
for (const auto & part : getDataPartsStateRange(DataPartState::Active))
{
if (part->isEmpty())
continue;
if (max_added_blocks)
{
auto blocks_iterator = max_added_blocks->find(part->info.partition_id);
if (blocks_iterator == max_added_blocks->end() || part->info.max_block > blocks_iterator->second)
continue;
}
func(part);
}
}
std::optional<UInt64> StorageReplicatedMergeTree::totalRows(const Settings & settings) const
{
UInt64 res = 0;
foreachActiveParts([&res](auto & part) { res += part->rows_count; }, settings.select_sequential_consistency);
return res;
}
std::optional<UInt64> StorageReplicatedMergeTree::totalRowsByPartitionPredicate(const SelectQueryInfo & query_info, ContextPtr local_context) const
{
DataPartsVector parts;
foreachActiveParts([&](auto & part) { parts.push_back(part); }, local_context->getSettingsRef().select_sequential_consistency);
return totalRowsByPartitionPredicateImpl(query_info, local_context, parts);
}
std::optional<UInt64> StorageReplicatedMergeTree::totalBytes(const Settings & settings) const
{
UInt64 res = 0;
foreachActiveParts([&res](auto & part) { res += part->getBytesOnDisk(); }, settings.select_sequential_consistency);
return res;
}
void StorageReplicatedMergeTree::assertNotReadonly() const
{
if (is_readonly)
throw Exception(ErrorCodes::TABLE_IS_READ_ONLY, "Table is in readonly mode (replica path: {})", replica_path);
}
SinkToStoragePtr StorageReplicatedMergeTree::write(const ASTPtr & /*query*/, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context, bool async_insert)
{
if (!initialization_done)
throw Exception(ErrorCodes::NOT_INITIALIZED, "Table is not initialized yet");
/// If table is read-only because it doesn't have metadata in zk yet, then it's not possible to insert into it
/// Without this check, we'll write data parts on disk, and afterwards will remove them since we'll fail to commit them into zk
/// In case of remote storage like s3, it'll generate unnecessary PUT requests
if (is_readonly && (!has_metadata_in_zookeeper.has_value() || false == has_metadata_in_zookeeper.value()))
throw Exception(
ErrorCodes::TABLE_IS_READ_ONLY,
"Table is in readonly mode since table metadata was not found in zookeeper: replica_path={}",
replica_path);
const auto storage_settings_ptr = getSettings();
const Settings & query_settings = local_context->getSettingsRef();
bool deduplicate = storage_settings_ptr->replicated_deduplication_window != 0 && query_settings.insert_deduplicate;
bool async_deduplicate = async_insert && query_settings.async_insert_deduplicate && storage_settings_ptr->replicated_deduplication_window_for_async_inserts != 0 && query_settings.insert_deduplicate;
if (async_deduplicate)
return std::make_shared<ReplicatedMergeTreeSinkWithAsyncDeduplicate>(
*this, metadata_snapshot, query_settings.insert_quorum.valueOr(0),
query_settings.insert_quorum_timeout.totalMilliseconds(),
query_settings.max_partitions_per_insert_block,
query_settings.insert_quorum_parallel,
deduplicate,
query_settings.insert_quorum.is_auto,
local_context);
// TODO: should we also somehow pass list of columns to deduplicate on to the ReplicatedMergeTreeSink?
return std::make_shared<ReplicatedMergeTreeSink>(
*this, metadata_snapshot, query_settings.insert_quorum.valueOr(0),
query_settings.insert_quorum_timeout.totalMilliseconds(),
query_settings.max_partitions_per_insert_block,
query_settings.insert_quorum_parallel,
deduplicate,
query_settings.insert_quorum.is_auto,
local_context);
}
std::optional<QueryPipeline> StorageReplicatedMergeTree::distributedWriteFromClusterStorage(const std::shared_ptr<IStorageCluster> & src_storage_cluster, const ASTInsertQuery & query, ContextPtr local_context)
{
const auto & settings = local_context->getSettingsRef();
auto extension = src_storage_cluster->getTaskIteratorExtension(nullptr, local_context);
/// Here we won't check that the cluster formed from table replicas is a subset of a cluster specified in s3Cluster/hdfsCluster table function
auto src_cluster = src_storage_cluster->getCluster(local_context);
/// Actually the query doesn't change, we just serialize it to string
String query_str;
{
WriteBufferFromOwnString buf;
IAST::FormatSettings ast_format_settings(buf, /*one_line*/ true, /*hilite*/ false, /*always_quote_identifiers*/ true);
query.IAST::format(ast_format_settings);
query_str = buf.str();
}
QueryPipeline pipeline;
ContextMutablePtr query_context = Context::createCopy(local_context);
query_context->increaseDistributedDepth();
for (const auto & replicas : src_cluster->getShardsAddresses())
{
/// There will be only one replica, because we consider each replica as a shard
for (const auto & node : replicas)
{
auto connection = std::make_shared<Connection>(
node.host_name, node.port, query_context->getGlobalContext()->getCurrentDatabase(),
node.user, node.password, node.quota_key, node.cluster, node.cluster_secret,
"ParallelInsertSelectInititiator",
node.compression,
node.secure
);
auto remote_query_executor = std::make_shared<RemoteQueryExecutor>(
connection,
query_str,
Block{},
query_context,
/*throttler=*/nullptr,
Scalars{},
Tables{},
QueryProcessingStage::Complete,
extension);
QueryPipeline remote_pipeline(std::make_shared<RemoteSource>(remote_query_executor, false, settings.async_socket_for_remote, settings.async_query_sending_for_remote));
remote_pipeline.complete(std::make_shared<EmptySink>(remote_query_executor->getHeader()));
pipeline.addCompletedPipeline(std::move(remote_pipeline));
}
}
return pipeline;
}
std::optional<QueryPipeline> StorageReplicatedMergeTree::distributedWrite(const ASTInsertQuery & query, ContextPtr local_context)
{
/// Do not enable parallel distributed INSERT SELECT in case when query probably comes from another server
if (local_context->getClientInfo().query_kind != ClientInfo::QueryKind::INITIAL_QUERY)
return {};
const Settings & settings = local_context->getSettingsRef();
if (settings.max_distributed_depth && local_context->getClientInfo().distributed_depth >= settings.max_distributed_depth)
throw Exception(ErrorCodes::TOO_LARGE_DISTRIBUTED_DEPTH, "Maximum distributed depth exceeded");
auto & select = query.select->as<ASTSelectWithUnionQuery &>();
StoragePtr src_storage;
if (select.list_of_selects->children.size() == 1)
{
if (auto * select_query = select.list_of_selects->children.at(0)->as<ASTSelectQuery>())
{
JoinedTables joined_tables(Context::createCopy(local_context), *select_query);
if (joined_tables.tablesCount() == 1)
{
src_storage = joined_tables.getLeftTableStorage();
}
}
}
if (!src_storage)
return {};
if (auto src_distributed = std::dynamic_pointer_cast<IStorageCluster>(src_storage))
{
return distributedWriteFromClusterStorage(src_distributed, query, local_context);
}
else if (local_context->getClientInfo().distributed_depth == 0)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Parallel distributed INSERT SELECT is not possible. Reason: distributed "
"reading into Replicated table is supported only from *Cluster table functions, but got {} storage", src_storage->getName());
}
return {};
}
bool StorageReplicatedMergeTree::optimize(
const ASTPtr &,
const StorageMetadataPtr &,
const ASTPtr & partition,
bool final,
bool deduplicate,
const Names & deduplicate_by_columns,
bool cleanup,
ContextPtr query_context)
{
/// NOTE: exclusive lock cannot be used here, since this may lead to deadlock (see comments below),
/// but it should be safe to use non-exclusive to avoid dropping parts that may be required for processing queue.
auto table_lock = lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
assertNotReadonly();
if (!is_leader)
throw Exception(ErrorCodes::NOT_A_LEADER, "OPTIMIZE cannot be done on this replica because it is not a leader");
if (cleanup)
LOG_DEBUG(log, "Cleanup the ReplicatedMergeTree.");
auto handle_noop = [&]<typename... Args>(FormatStringHelper<Args...> fmt_string, Args && ...args)
{
PreformattedMessage message = fmt_string.format(std::forward<Args>(args)...);
LOG_DEBUG(log, message);
if (query_context->getSettingsRef().optimize_throw_if_noop)
throw Exception(std::move(message), ErrorCodes::CANNOT_ASSIGN_OPTIMIZE);
return false;
};
auto zookeeper = getZooKeeperAndAssertNotReadonly();
const auto storage_settings_ptr = getSettings();
auto metadata_snapshot = getInMemoryMetadataPtr();
std::vector<ReplicatedMergeTreeLogEntryData> merge_entries;
auto try_assign_merge = [&](const String & partition_id) -> bool
{
constexpr size_t max_retries = 10;
size_t try_no = 0;
for (; try_no < max_retries; ++try_no)
{
/// We must select parts for merge under merge_selecting_mutex because other threads
/// (merge_selecting_thread or OPTIMIZE queries) could assign new merges.
std::lock_guard merge_selecting_lock(merge_selecting_mutex);
PartitionIdsHint partition_ids_hint;
if (partition_id.empty())
{
partition_ids_hint = getAllPartitionIds();
}
else
{
auto parts_lock = lockParts();
if (!getAnyPartInPartition(partition_id, parts_lock))
handle_noop("Cannot select parts for optimization: there are no parts in partition {}", partition_id);
partition_ids_hint.insert(partition_id);
}
ReplicatedMergeTreeMergePredicate can_merge = queue.getMergePredicate(zookeeper, std::move(partition_ids_hint));
auto future_merged_part = std::make_shared<FutureMergedMutatedPart>();
if (storage_settings.get()->assign_part_uuids)
future_merged_part->uuid = UUIDHelpers::generateV4();
constexpr const char * unknown_disable_reason = "unknown reason";
String disable_reason = unknown_disable_reason;
SelectPartsDecision select_decision = SelectPartsDecision::CANNOT_SELECT;
if (partition_id.empty())
{
select_decision = merger_mutator.selectPartsToMerge(
future_merged_part, /* aggressive */ true, storage_settings_ptr->max_bytes_to_merge_at_max_space_in_pool,
can_merge, /* merge_with_ttl_allowed */ false, NO_TRANSACTION_PTR, disable_reason);
}
else
{
select_decision = merger_mutator.selectAllPartsToMergeWithinPartition(
future_merged_part, can_merge, partition_id, final, metadata_snapshot, NO_TRANSACTION_PTR,
disable_reason, query_context->getSettingsRef().optimize_skip_merged_partitions);
}
/// If there is nothing to merge then we treat this merge as successful (needed for optimize final optimization)
if (select_decision == SelectPartsDecision::NOTHING_TO_MERGE)
return false;
if (select_decision != SelectPartsDecision::SELECTED)
{
constexpr const char * message_fmt = "Cannot select parts for optimization: {}";
assert(disable_reason != unknown_disable_reason);
if (!partition_id.empty())
disable_reason += fmt::format(" (in partition {})", partition_id);
return handle_noop(message_fmt, disable_reason);
}
ReplicatedMergeTreeLogEntryData merge_entry;
CreateMergeEntryResult create_result = createLogEntryToMergeParts(
zookeeper, future_merged_part->parts,
future_merged_part->name,
future_merged_part->uuid,
future_merged_part->part_format,
deduplicate, deduplicate_by_columns,
cleanup,
&merge_entry, can_merge.getVersion(),
future_merged_part->merge_type);
if (create_result == CreateMergeEntryResult::MissingPart)
{
static constexpr const char * message_fmt = "Can't create merge queue node in ZooKeeper, because some parts are missing";
return handle_noop(message_fmt);
}
if (create_result == CreateMergeEntryResult::LogUpdated)
continue;
merge_entries.push_back(std::move(merge_entry));
return true;
}
assert(try_no == max_retries);
static constexpr const char * message_fmt = "Can't create merge queue node in ZooKeeper, because log was updated in every of {} tries";
return handle_noop(message_fmt, try_no);
};
bool assigned = false;
if (!partition && final)
{
if (cleanup && this->merging_params.mode != MergingParams::Mode::Replacing)
{
constexpr const char * message = "Cannot OPTIMIZE with CLEANUP table: {}";
String disable_reason = "only ReplacingMergeTree can be CLEANUP";
throw Exception(ErrorCodes::CANNOT_ASSIGN_OPTIMIZE, message, disable_reason);
}
DataPartsVector data_parts = getVisibleDataPartsVector(query_context);
std::unordered_set<String> partition_ids;
for (const DataPartPtr & part : data_parts)
partition_ids.emplace(part->info.partition_id);
for (const String & partition_id : partition_ids)
{
assigned = try_assign_merge(partition_id);
if (!assigned)
break;
}
}
else
{
String partition_id;
if (partition)
partition_id = getPartitionIDFromQuery(partition, query_context);
assigned = try_assign_merge(partition_id);
}
table_lock.reset();
for (auto & merge_entry : merge_entries)
waitForLogEntryToBeProcessedIfNecessary(merge_entry, query_context);
return assigned;
}
bool StorageReplicatedMergeTree::executeMetadataAlter(const StorageReplicatedMergeTree::LogEntry & entry)
{
auto current_metadata = getInMemoryMetadataPtr();
if (entry.alter_version < current_metadata->getMetadataVersion())
{
/// TODO Can we replace it with LOGICAL_ERROR?
/// As for now, it may rarely happen due to reordering of ALTER_METADATA entries in the queue of
/// non-initial replica and also may happen after stale replica recovery.
LOG_WARNING(log, "Attempt to update metadata of version {} "
"to older version {} when processing log entry {}: {}",
current_metadata->getMetadataVersion(), entry.alter_version, entry.znode_name, entry.toString());
return true;
}
auto zookeeper = getZooKeeper();
auto columns_from_entry = ColumnsDescription::parse(entry.columns_str);
auto metadata_from_entry = ReplicatedMergeTreeTableMetadata::parse(entry.metadata_str);
MergeTreeData::DataParts parts;
/// If metadata nodes have changed, we will update table structure locally.
Coordination::Requests requests;
requests.emplace_back(zkutil::makeSetRequest(fs::path(replica_path) / "columns", entry.columns_str, -1));
requests.emplace_back(zkutil::makeSetRequest(fs::path(replica_path) / "metadata", entry.metadata_str, -1));
auto table_id = getStorageID();
auto alter_context = getContext();
auto database = DatabaseCatalog::instance().getDatabase(table_id.database_name);
bool is_in_replicated_database = database->getEngineName() == "Replicated";
if (is_in_replicated_database)
{
auto mutable_alter_context = Context::createCopy(getContext());
const auto * replicated = dynamic_cast<const DatabaseReplicated *>(database.get());
mutable_alter_context->makeQueryContext();
auto alter_txn = std::make_shared<ZooKeeperMetadataTransaction>(zookeeper, replicated->getZooKeeperPath(),
/* is_initial_query */ false, /* task_zk_path */ "");
mutable_alter_context->initZooKeeperMetadataTransaction(alter_txn);
alter_context = mutable_alter_context;
for (auto & op : requests)
alter_txn->addOp(std::move(op));
requests.clear();
/// Requests will be executed by database in setTableStructure
}
else
{
zookeeper->multi(requests);
}
{
auto table_lock_holder = lockForShare(RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
auto alter_lock_holder = lockForAlter(getSettings()->lock_acquire_timeout_for_background_operations);
LOG_INFO(log, "Metadata changed in ZooKeeper. Applying changes locally.");
auto metadata_diff = ReplicatedMergeTreeTableMetadata(*this, getInMemoryMetadataPtr()).checkAndFindDiff(metadata_from_entry, getInMemoryMetadataPtr()->getColumns(), getContext());
setTableStructure(table_id, alter_context, std::move(columns_from_entry), metadata_diff, entry.alter_version);
current_metadata = getInMemoryMetadataPtr();
LOG_INFO(log, "Applied changes to the metadata of the table. Current metadata version: {}", current_metadata->getMetadataVersion());
}
{
/// Reset Object columns, because column of type
/// Object may be added or dropped by alter.
auto parts_lock = lockParts();
resetObjectColumnsFromActiveParts(parts_lock);
}
/// This transaction may not happen, but it's OK, because on the next retry we will eventually create/update this node
/// TODO Maybe do in in one transaction for Replicated database?
zookeeper->createOrUpdate(fs::path(replica_path) / "metadata_version", std::to_string(current_metadata->getMetadataVersion()), zkutil::CreateMode::Persistent);
return true;
}
PartitionBlockNumbersHolder StorageReplicatedMergeTree::allocateBlockNumbersInAffectedPartitions(
const MutationCommands & commands, ContextPtr query_context, const zkutil::ZooKeeperPtr & zookeeper) const
{
const std::set<String> mutation_affected_partition_ids = getPartitionIdsAffectedByCommands(commands, query_context);
if (mutation_affected_partition_ids.size() == 1)
{
const auto & affected_partition_id = *mutation_affected_partition_ids.cbegin();
auto block_number_holder = allocateBlockNumber(affected_partition_id, zookeeper);
if (!block_number_holder.has_value())
return {};
auto block_number = block_number_holder->getNumber(); /// Avoid possible UB due to std::move
return {{{affected_partition_id, block_number}}, std::move(block_number_holder)};
}
else
{
/// TODO: Implement optimal block number acquisition algorithm in multiple (but not all) partitions
EphemeralLocksInAllPartitions lock_holder(
fs::path(zookeeper_path) / "block_numbers", "block-", fs::path(zookeeper_path) / "temp", *zookeeper);
PartitionBlockNumbersHolder::BlockNumbersType block_numbers;
for (const auto & lock : lock_holder.getLocks())
{
if (mutation_affected_partition_ids.empty() || mutation_affected_partition_ids.contains(lock.partition_id))
block_numbers[lock.partition_id] = lock.number;
}
return {std::move(block_numbers), std::move(lock_holder)};
}
}
void StorageReplicatedMergeTree::alter(
const AlterCommands & commands, ContextPtr query_context, AlterLockHolder & table_lock_holder)
{
assertNotReadonly();
auto table_id = getStorageID();
if (commands.isSettingsAlter())
{
/// We don't replicate storage_settings_ptr ALTER. It's local operation.
/// Also we don't upgrade alter lock to table structure lock.
StorageInMemoryMetadata future_metadata = getInMemoryMetadata();
commands.apply(future_metadata, query_context);
merge_strategy_picker.refreshState();
changeSettings(future_metadata.settings_changes, table_lock_holder);
DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(query_context, table_id, future_metadata);
return;
}
auto ast_to_str = [](ASTPtr query) -> String
{
if (!query)
return "";
return queryToString(query);
};
const auto zookeeper = getZooKeeperAndAssertNotReadonly();
std::optional<ReplicatedMergeTreeLogEntryData> alter_entry;
std::optional<String> mutation_znode;
while (true)
{
/// Clear nodes from previous iteration
alter_entry.emplace();
mutation_znode.reset();
auto current_metadata = getInMemoryMetadataPtr();
StorageInMemoryMetadata future_metadata = *current_metadata;
commands.apply(future_metadata, query_context);
ReplicatedMergeTreeTableMetadata future_metadata_in_zk(*this, current_metadata);
if (ast_to_str(future_metadata.sorting_key.definition_ast) != ast_to_str(current_metadata->sorting_key.definition_ast))
{
/// We serialize definition_ast as list, because code which apply ALTER (setTableStructure) expect serialized non empty expression
/// list here and we cannot change this representation for compatibility. Also we have preparsed AST `sorting_key.expression_list_ast`
/// in KeyDescription, but it contain version column for VersionedCollapsingMergeTree, which shouldn't be defined as a part of key definition AST.
/// So the best compatible way is just to convert definition_ast to list and serialize it. In all other places key.expression_list_ast should be used.
future_metadata_in_zk.sorting_key = serializeAST(*extractKeyExpressionList(future_metadata.sorting_key.definition_ast));
}
if (ast_to_str(future_metadata.sampling_key.definition_ast) != ast_to_str(current_metadata->sampling_key.definition_ast))
future_metadata_in_zk.sampling_expression = serializeAST(*extractKeyExpressionList(future_metadata.sampling_key.definition_ast));
if (ast_to_str(future_metadata.partition_key.definition_ast) != ast_to_str(current_metadata->partition_key.definition_ast))
future_metadata_in_zk.partition_key = serializeAST(*extractKeyExpressionList(future_metadata.partition_key.definition_ast));
if (ast_to_str(future_metadata.table_ttl.definition_ast) != ast_to_str(current_metadata->table_ttl.definition_ast))
{
if (future_metadata.table_ttl.definition_ast)
future_metadata_in_zk.ttl_table = serializeAST(*future_metadata.table_ttl.definition_ast);
else /// TTL was removed
future_metadata_in_zk.ttl_table = "";
}
String new_indices_str = future_metadata.secondary_indices.toString();
if (new_indices_str != current_metadata->secondary_indices.toString())
future_metadata_in_zk.skip_indices = new_indices_str;
String new_projections_str = future_metadata.projections.toString();
if (new_projections_str != current_metadata->projections.toString())
future_metadata_in_zk.projections = new_projections_str;
String new_constraints_str = future_metadata.constraints.toString();
if (new_constraints_str != current_metadata->constraints.toString())
future_metadata_in_zk.constraints = new_constraints_str;
Coordination::Requests ops;
size_t alter_path_idx = std::numeric_limits<size_t>::max();
size_t mutation_path_idx = std::numeric_limits<size_t>::max();
String new_metadata_str = future_metadata_in_zk.toString();
ops.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "metadata", new_metadata_str, current_metadata->getMetadataVersion()));
String new_columns_str = future_metadata.columns.toString();
ops.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "columns", new_columns_str, -1));
if (ast_to_str(current_metadata->settings_changes) != ast_to_str(future_metadata.settings_changes))
{
/// Just change settings
StorageInMemoryMetadata metadata_copy = *current_metadata;
metadata_copy.settings_changes = future_metadata.settings_changes;
changeSettings(metadata_copy.settings_changes, table_lock_holder);
DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(query_context, table_id, metadata_copy);
}
/// We can be sure, that in case of successful commit in zookeeper our
/// version will increments by 1. Because we update with version check.
int new_metadata_version = current_metadata->getMetadataVersion() + 1;
alter_entry->type = LogEntry::ALTER_METADATA;
alter_entry->source_replica = replica_name;
alter_entry->metadata_str = new_metadata_str;
alter_entry->columns_str = new_columns_str;
alter_entry->alter_version = new_metadata_version;
alter_entry->create_time = time(nullptr);
auto maybe_mutation_commands = commands.getMutationCommands(
*current_metadata,
query_context->getSettingsRef().materialize_ttl_after_modify,
query_context);
bool have_mutation = !maybe_mutation_commands.empty();
alter_entry->have_mutation = have_mutation;
alter_path_idx = ops.size();
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(zookeeper_path) / "log/log-", alter_entry->toString(), zkutil::CreateMode::PersistentSequential));
PartitionBlockNumbersHolder partition_block_numbers_holder;
ReplicatedMergeTreeMutationEntry mutation_entry;
if (have_mutation)
{
delayMutationOrThrowIfNeeded(&partial_shutdown_event, query_context);
const String mutations_path(fs::path(zookeeper_path) / "mutations");
mutation_entry.alter_version = new_metadata_version;
mutation_entry.source_replica = replica_name;
mutation_entry.commands = std::move(maybe_mutation_commands);
Coordination::Stat mutations_stat;
zookeeper->get(mutations_path, &mutations_stat);
partition_block_numbers_holder =
allocateBlockNumbersInAffectedPartitions(mutation_entry.commands, query_context, zookeeper);
mutation_entry.block_numbers = partition_block_numbers_holder.getBlockNumbers();
mutation_entry.create_time = time(nullptr);
ops.emplace_back(zkutil::makeSetRequest(mutations_path, String(), mutations_stat.version));
mutation_path_idx = ops.size();
ops.emplace_back(
zkutil::makeCreateRequest(fs::path(mutations_path) / "", mutation_entry.toString(), zkutil::CreateMode::PersistentSequential));
}
if (auto txn = query_context->getZooKeeperMetadataTransaction())
{
/// It would be better to clone ops instead of moving, so we could retry on ZBADVERSION,
/// but clone() is not implemented for Coordination::Request.
txn->moveOpsTo(ops);
/// NOTE: IDatabase::alterTable(...) is called when executing ALTER_METADATA queue entry without query context,
/// so we have to update metadata of DatabaseReplicated here.
String metadata_zk_path = fs::path(txn->getDatabaseZooKeeperPath()) / "metadata" / escapeForFileName(table_id.table_name);
auto ast = DatabaseCatalog::instance().getDatabase(table_id.database_name)->getCreateTableQuery(table_id.table_name, query_context);
applyMetadataChangesToCreateQuery(ast, future_metadata);
ops.emplace_back(zkutil::makeSetRequest(metadata_zk_path, getObjectDefinitionFromCreateQuery(ast), -1));
}
Coordination::Responses results;
Coordination::Error rc = zookeeper->tryMulti(ops, results);
/// For the sake of consistency with mechanics of concurrent background process of assigning parts merge tasks
/// this placeholder must be held up until the moment of committing into ZK of the mutation entry
/// See ReplicatedMergeTreeMergePredicate::canMergeTwoParts() method
partition_block_numbers_holder.reset();
if (rc == Coordination::Error::ZOK)
{
if (have_mutation)
{
/// ALTER_METADATA record in replication /log
String alter_path = dynamic_cast<const Coordination::CreateResponse &>(*results[alter_path_idx]).path_created;
alter_entry->znode_name = alter_path.substr(alter_path.find_last_of('/') + 1);
/// ReplicatedMergeTreeMutationEntry record in /mutations
String mutation_path = dynamic_cast<const Coordination::CreateResponse &>(*results[mutation_path_idx]).path_created;
mutation_znode = mutation_path.substr(mutation_path.find_last_of('/') + 1);
LOG_DEBUG(log, "Created log entry {} to update table metadata to version {}, created a mutation {} (data versions: {})",
alter_entry->znode_name, alter_entry->alter_version, *mutation_znode, mutation_entry.getBlockNumbersForLogs());
}
else
{
/// ALTER_METADATA record in replication /log
String alter_path = dynamic_cast<const Coordination::CreateResponse &>(*results[alter_path_idx]).path_created;
alter_entry->znode_name = alter_path.substr(alter_path.find_last_of('/') + 1);
LOG_DEBUG(log, "Created log entry {} to update table metadata to version {}",
alter_entry->znode_name, alter_entry->alter_version);
}
break;
}
else if (rc == Coordination::Error::ZBADVERSION)
{
if (results[0]->error != Coordination::Error::ZOK)
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Metadata on replica is not up to date with common metadata in Zookeeper. "
"It means that this replica still not applied some of previous alters."
" Probably too many alters executing concurrently (highly not recommended). "
"You can retry this error");
/// Cannot retry automatically, because some zookeeper ops were lost on the first attempt. Will retry on DDLWorker-level.
if (query_context->getZooKeeperMetadataTransaction())
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot execute alter, because mutations version was suddenly changed due "
"to concurrent alter");
continue;
}
else
{
throw Coordination::Exception::fromMessage(rc, "Alter cannot be assigned because of Zookeeper error");
}
}
table_lock_holder.unlock();
LOG_DEBUG(log, "Updated shared metadata nodes in ZooKeeper. Waiting for replicas to apply changes.");
waitForLogEntryToBeProcessedIfNecessary(*alter_entry, query_context, "Some replicas doesn't finish metadata alter: ");
if (mutation_znode)
{
LOG_DEBUG(log, "Metadata changes applied. Will wait for data changes.");
merge_selecting_task->schedule();
waitMutation(*mutation_znode, query_context->getSettingsRef().alter_sync);
LOG_DEBUG(log, "Data changes applied.");
}
}
/// If new version returns ordinary name, else returns part name containing the first and last month of the month
/// NOTE: use it in pair with getFakePartCoveringAllPartsInPartition(...)
String getPartNamePossiblyFake(MergeTreeDataFormatVersion format_version, const MergeTreePartInfo & part_info)
{
if (format_version < MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING)
{
/// The date range is all month long.
const auto & lut = DateLUT::serverTimezoneInstance();
time_t start_time = lut.YYYYMMDDToDate(parse<UInt32>(part_info.partition_id + "01"));
DayNum left_date = DayNum(lut.toDayNum(start_time).toUnderType());
DayNum right_date = DayNum(static_cast<size_t>(left_date) + lut.daysInMonth(start_time) - 1);
return part_info.getPartNameV0(left_date, right_date);
}
return part_info.getPartNameV1();
}
bool StorageReplicatedMergeTree::getFakePartCoveringAllPartsInPartition(
const String & partition_id, MergeTreePartInfo & part_info,
std::optional<EphemeralLockInZooKeeper> & delimiting_block_lock, bool for_replace_range)
{
/// Even if there is no data in the partition, you still need to mark the range for deletion.
/// - Because before executing DETACH, tasks for downloading parts to this partition can be executed.
Int64 left = 0;
/** Let's skip one number in `block_numbers` for the partition being deleted, and we will only delete parts until this number.
* This prohibits merges of deleted parts with the new inserted
* Invariant: merges of deleted parts with other parts do not appear in the log.
* NOTE: If you need to similarly support a `DROP PART` request, you will have to think of some new mechanism for it,
* to guarantee this invariant.
*/
Int64 right;
Int64 mutation_version;
{
delimiting_block_lock = allocateBlockNumber(partition_id, getZooKeeper());
right = delimiting_block_lock->getNumber();
/// Make sure we cover all parts in drop range.
/// There might be parts with mutation version greater than current block number
/// if some part mutation has been assigned after block number allocation, but before creation of DROP_RANGE entry.
mutation_version = MergeTreePartInfo::MAX_BLOCK_NUMBER;
}
if (for_replace_range)
{
/// NOTE Do not decrement max block number for REPLACE_RANGE, because there are invariants:
/// - drop range for REPLACE PARTITION must contain at least 2 blocks (1 skipped block and at least 1 real block)
/// - drop range for MOVE PARTITION/ATTACH PARTITION FROM always contains 1 block
/// NOTE UINT_MAX was previously used as max level for REPLACE/MOVE PARTITION (it was incorrect)
part_info = MergeTreePartInfo(partition_id, left, right, MergeTreePartInfo::MAX_LEVEL, mutation_version);
return right != 0;
}
/// Empty partition.
if (right == 0)
return false;
--right;
/// Artificial high level is chosen, to make this part "covering" all parts inside.
part_info = MergeTreePartInfo(partition_id, left, right, MergeTreePartInfo::MAX_LEVEL, mutation_version);
return true;
}
void StorageReplicatedMergeTree::restoreMetadataInZooKeeper()
{
LOG_INFO(log, "Restoring replica metadata");
if (!initialization_done)
throw Exception(ErrorCodes::NOT_INITIALIZED, "Table is not initialized yet");
if (!is_readonly)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Replica must be readonly");
if (getZooKeeper()->exists(replica_path))
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Replica path is present at {} - nothing to restore. "
"If you are sure that metadata is lost and that replica path contains some garbage, "
"then use SYSTEM DROP REPLICA query first.", replica_path);
if (has_metadata_in_zookeeper.has_value() && *has_metadata_in_zookeeper)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Replica has metadata in ZooKeeper: "
"it's either a bug or it's a result of manual intervention to ZooKeeper");
if (are_restoring_replica.exchange(true))
throw Exception(ErrorCodes::CONCURRENT_ACCESS_NOT_SUPPORTED, "Replica restoration in progress");
SCOPE_EXIT({ are_restoring_replica.store(false); });
auto metadata_snapshot = getInMemoryMetadataPtr();
waitForOutdatedPartsToBeLoaded();
const DataPartsVector all_parts = getAllDataPartsVector();
Strings active_parts_names;
/// Why all parts (not only Active) are moved to detached/:
/// After ZK metadata restoration ZK resets sequential counters (including block number counters), so one may
/// potentially encounter a situation that a part we want to attach already exists.
for (const auto & part : all_parts)
{
if (part->getState() == DataPartState::Active)
active_parts_names.push_back(part->name);
forcefullyMovePartToDetachedAndRemoveFromMemory(part);
}
LOG_INFO(log, "Moved all parts to detached/");
const bool is_first_replica = createTableIfNotExists(metadata_snapshot);
LOG_INFO(log, "Created initial ZK nodes, replica is first: {}", is_first_replica);
if (!is_first_replica)
createReplica(metadata_snapshot);
createNewZooKeeperNodes();
LOG_INFO(log, "Created ZK nodes for table");
has_metadata_in_zookeeper = true;
if (is_first_replica)
for (const String& part_name : active_parts_names)
attachPartition(std::make_shared<ASTLiteral>(part_name), metadata_snapshot, true, getContext());
LOG_INFO(log, "Attached all partitions, starting table");
startupImpl(/* from_attach_thread */ false);
}
void StorageReplicatedMergeTree::dropPartNoWaitNoThrow(const String & part_name)
{
assertNotReadonly();
if (!is_leader)
throw Exception(ErrorCodes::NOT_A_LEADER, "DROP PART cannot be done on this replica because it is not a leader");
zkutil::ZooKeeperPtr zookeeper = getZooKeeperAndAssertNotReadonly();
LogEntry entry;
dropPartImpl(zookeeper, part_name, entry, /*detach=*/ false, /*throw_if_noop=*/ false);
}
void StorageReplicatedMergeTree::dropPart(const String & part_name, bool detach, ContextPtr query_context)
{
assertNotReadonly();
if (!is_leader)
throw Exception(ErrorCodes::NOT_A_LEADER, "DROP PART cannot be done on this replica because it is not a leader");
zkutil::ZooKeeperPtr zookeeper = getZooKeeperAndAssertNotReadonly();
LogEntry entry;
dropPartImpl(zookeeper, part_name, entry, detach, /*throw_if_noop=*/ true);
waitForLogEntryToBeProcessedIfNecessary(entry, query_context);
}
void StorageReplicatedMergeTree::dropAllPartitionsImpl(const zkutil::ZooKeeperPtr & zookeeper, bool detach, ContextPtr query_context)
{
Strings partitions = zookeeper->getChildren(fs::path(zookeeper_path) / "block_numbers");
std::vector<LogEntryPtr> entries;
dropAllPartsInPartitions(*zookeeper, partitions, entries, query_context, detach);
for (const auto & entry : entries)
{
waitForLogEntryToBeProcessedIfNecessary(*entry, query_context);
auto drop_range_info = MergeTreePartInfo::fromPartName(entry->new_part_name, format_version);
cleanLastPartNode(drop_range_info.partition_id);
}
}
void StorageReplicatedMergeTree::dropPartition(const ASTPtr & partition, bool detach, ContextPtr query_context)
{
assertNotReadonly();
if (!is_leader)
throw Exception(ErrorCodes::NOT_A_LEADER, "DROP PARTITION cannot be done on this replica because it is not a leader");
zkutil::ZooKeeperPtr zookeeper = getZooKeeperAndAssertNotReadonly();
const auto * partition_ast = partition->as<ASTPartition>();
if (partition_ast && partition_ast->all)
{
dropAllPartitionsImpl(zookeeper, detach, query_context);
}
else
{
String partition_id = getPartitionIDFromQuery(partition, query_context);
auto entry = dropAllPartsInPartition(*zookeeper, partition_id, query_context, detach);
if (entry)
{
waitForLogEntryToBeProcessedIfNecessary(*entry, query_context);
cleanLastPartNode(partition_id);
}
}
}
void StorageReplicatedMergeTree::truncate(
const ASTPtr &, const StorageMetadataPtr &, ContextPtr query_context, TableExclusiveLockHolder & table_lock)
{
table_lock.release(); /// Truncate is done asynchronously.
assertNotReadonly();
if (!is_leader)
throw Exception(ErrorCodes::NOT_A_LEADER, "TRUNCATE cannot be done on this replica because it is not a leader");
waitForOutdatedPartsToBeLoaded();
zkutil::ZooKeeperPtr zookeeper = getZooKeeperAndAssertNotReadonly();
dropAllPartitionsImpl(zookeeper, /* detach */ false, query_context);
}
PartitionCommandsResultInfo StorageReplicatedMergeTree::attachPartition(
const ASTPtr & partition,
const StorageMetadataPtr & metadata_snapshot,
bool attach_part,
ContextPtr query_context)
{
/// Allow ATTACH PARTITION on readonly replica when restoring it.
if (!are_restoring_replica)
assertNotReadonly();
PartitionCommandsResultInfo results;
PartsTemporaryRename renamed_parts(*this, "detached/");
MutableDataPartsVector loaded_parts = tryLoadPartsToAttach(partition, attach_part, query_context, renamed_parts);
/// TODO Allow to use quorum here.
ReplicatedMergeTreeSink output(*this, metadata_snapshot, /* quorum */ 0, /* quorum_timeout_ms */ 0, /* max_parts_per_block */ 0,
/* quorum_parallel */ false, query_context->getSettingsRef().insert_deduplicate,
/* majority_quorum */ false, query_context, /*is_attach*/true);
for (size_t i = 0; i < loaded_parts.size(); ++i)
{
const String old_name = loaded_parts[i]->name;
output.writeExistingPart(loaded_parts[i]);
renamed_parts.old_and_new_names[i].old_name.clear();
LOG_DEBUG(log, "Attached part {} as {}", old_name, loaded_parts[i]->name);
results.push_back(PartitionCommandResultInfo{
.partition_id = loaded_parts[i]->info.partition_id,
.part_name = loaded_parts[i]->name,
.old_part_name = old_name,
});
}
return results;
}
void StorageReplicatedMergeTree::checkTableCanBeDropped() const
{
auto table_id = getStorageID();
getContext()->checkTableCanBeDropped(table_id.database_name, table_id.table_name, getTotalActiveSizeInBytes());
}
void StorageReplicatedMergeTree::checkTableCanBeRenamed(const StorageID & new_name) const
{
if (renaming_restrictions == RenamingRestrictions::ALLOW_ANY)
return;
if (renaming_restrictions == RenamingRestrictions::DO_NOT_ALLOW)
{
auto old_name = getStorageID();
bool is_server_startup = Context::getGlobalContextInstance()->getApplicationType() == Context::ApplicationType::SERVER
&& !Context::getGlobalContextInstance()->isServerCompletelyStarted();
bool move_to_atomic = old_name.uuid == UUIDHelpers::Nil && new_name.uuid != UUIDHelpers::Nil;
bool likely_converting_ordinary_to_atomic = is_server_startup && move_to_atomic;
if (likely_converting_ordinary_to_atomic)
{
LOG_INFO(log, "Table {} should not be renamed, because zookeeper_path contains implicit 'database' or 'table' macro. "
"We cannot rename path in ZooKeeper, so path may become inconsistent with table name. "
"However, we allow renaming while converting Ordinary database to Atomic, because all tables will be renamed back",
old_name.getNameForLogs());
return;
}
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Cannot rename Replicated table, because zookeeper_path contains implicit 'database' "
"or 'table' macro. We cannot rename path "
"in ZooKeeper, so path may become inconsistent with table name. "
"If you really want to rename table, you should edit metadata file first and restart server or reattach the table.");
}
assert(renaming_restrictions == RenamingRestrictions::ALLOW_PRESERVING_UUID);
if (!new_name.hasUUID() && getStorageID().hasUUID())
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Cannot move Replicated table to Ordinary database, because zookeeper_path contains implicit "
"'uuid' macro. If you really want to rename table, you should edit metadata file first "
"and restart server or reattach the table.");
}
void StorageReplicatedMergeTree::rename(const String & new_path_to_table_data, const StorageID & new_table_id)
{
checkTableCanBeRenamed(new_table_id);
MergeTreeData::rename(new_path_to_table_data, new_table_id);
/// Update table name in zookeeper
if (!is_readonly)
{
/// We don't do it for readonly tables, because it will be updated on next table startup.
/// It is also Ok to skip ZK error for the same reason.
try
{
auto zookeeper = getZooKeeper();
zookeeper->set(fs::path(replica_path) / "host", getReplicatedMergeTreeAddress().toString());
}
catch (Coordination::Exception & e)
{
LOG_WARNING(log, "Cannot update the value of 'host' node (replica address) in ZooKeeper: {}", e.displayText());
}
}
/// TODO: You can update names of loggers.
}
bool StorageReplicatedMergeTree::existsNodeCached(const ZooKeeperWithFaultInjectionPtr & zookeeper, const std::string & path) const
{
{
std::lock_guard lock(existing_nodes_cache_mutex);
if (existing_nodes_cache.contains(path))
return true;
}
bool res = zookeeper->exists(path);
if (res)
{
std::lock_guard lock(existing_nodes_cache_mutex);
existing_nodes_cache.insert(path);
}
return res;
}
std::optional<EphemeralLockInZooKeeper> StorageReplicatedMergeTree::allocateBlockNumber(
const String & partition_id,
const zkutil::ZooKeeperPtr & zookeeper,
const String & zookeeper_block_id_path,
const String & zookeeper_path_prefix) const
{
return allocateBlockNumber(
partition_id, std::make_shared<ZooKeeperWithFaultInjection>(zookeeper), zookeeper_block_id_path, zookeeper_path_prefix);
}
template<typename T>
std::optional<EphemeralLockInZooKeeper> StorageReplicatedMergeTree::allocateBlockNumber(
const String & partition_id,
const ZooKeeperWithFaultInjectionPtr & zookeeper,
const T & zookeeper_block_id_path,
const String & zookeeper_path_prefix) const
{
String zookeeper_table_path;
if (zookeeper_path_prefix.empty())
zookeeper_table_path = zookeeper_path;
else
zookeeper_table_path = zookeeper_path_prefix;
String block_numbers_path = fs::path(zookeeper_table_path) / "block_numbers";
String partition_path = fs::path(block_numbers_path) / partition_id;
if (!existsNodeCached(zookeeper, partition_path))
{
Coordination::Requests ops;
/// Check that table is not being dropped ("host" is the first node that is removed on replica drop)
ops.push_back(zkutil::makeCheckRequest(fs::path(replica_path) / "host", -1));
ops.push_back(zkutil::makeCreateRequest(partition_path, "", zkutil::CreateMode::Persistent));
/// We increment data version of the block_numbers node so that it becomes possible
/// to check in a ZK transaction that the set of partitions didn't change
/// (unfortunately there is no CheckChildren op).
ops.push_back(zkutil::makeSetRequest(block_numbers_path, "", -1));
Coordination::Responses responses;
Coordination::Error code = zookeeper->tryMulti(ops, responses);
if (code != Coordination::Error::ZOK && code != Coordination::Error::ZNODEEXISTS)
zkutil::KeeperMultiException::check(code, ops, responses);
}
return createEphemeralLockInZooKeeper(
fs::path(partition_path) / "block-", fs::path(zookeeper_table_path) / "temp", zookeeper, zookeeper_block_id_path);
}
Strings StorageReplicatedMergeTree::tryWaitForAllReplicasToProcessLogEntry(
const String & table_zookeeper_path, const ReplicatedMergeTreeLogEntryData & entry, Int64 wait_for_inactive_timeout)
{
LOG_DEBUG(log, "Waiting for all replicas to process {}", entry.znode_name);
auto zookeeper = getZooKeeper();
Strings replicas = zookeeper->getChildren(fs::path(table_zookeeper_path) / "replicas");
Strings unwaited;
bool wait_for_inactive = wait_for_inactive_timeout != 0;
for (const String & replica : replicas)
{
if (wait_for_inactive || zookeeper->exists(fs::path(table_zookeeper_path) / "replicas" / replica / "is_active"))
{
if (!tryWaitForReplicaToProcessLogEntry(table_zookeeper_path, replica, entry, wait_for_inactive_timeout))
unwaited.push_back(replica);
}
else
{
unwaited.push_back(replica);
}
}
LOG_DEBUG(log, "Finished waiting for all replicas to process {}", entry.znode_name);
return unwaited;
}
void StorageReplicatedMergeTree::waitForAllReplicasToProcessLogEntry(
const String & table_zookeeper_path, const ReplicatedMergeTreeLogEntryData & entry, Int64 wait_for_inactive_timeout, const String & error_context)
{
Strings unfinished_replicas = tryWaitForAllReplicasToProcessLogEntry(table_zookeeper_path, entry, wait_for_inactive_timeout);
if (unfinished_replicas.empty())
return;
throw Exception(ErrorCodes::UNFINISHED, "{}Timeout exceeded while waiting for replicas {} to process entry {}. "
"Probably some replicas are inactive", error_context, fmt::join(unfinished_replicas, ", "), entry.znode_name);
}
void StorageReplicatedMergeTree::waitForLogEntryToBeProcessedIfNecessary(const ReplicatedMergeTreeLogEntryData & entry, ContextPtr query_context, const String & error_context)
{
/// If necessary, wait until the operation is performed on itself or on all replicas.
Int64 wait_for_inactive_timeout = query_context->getSettingsRef().replication_wait_for_inactive_replica_timeout;
if (query_context->getSettingsRef().alter_sync == 1)
{
bool finished = tryWaitForReplicaToProcessLogEntry(zookeeper_path, replica_name, entry, wait_for_inactive_timeout);
if (!finished)
{
throw Exception(ErrorCodes::UNFINISHED, "{}Log entry {} is not precessed on local replica, "
"most likely because the replica was shut down.", error_context, entry.znode_name);
}
}
else if (query_context->getSettingsRef().alter_sync == 2)
{
waitForAllReplicasToProcessLogEntry(zookeeper_path, entry, wait_for_inactive_timeout, error_context);
}
}
bool StorageReplicatedMergeTree::tryWaitForReplicaToProcessLogEntry(
const String & table_zookeeper_path, const String & replica, const ReplicatedMergeTreeLogEntryData & entry, Int64 wait_for_inactive_timeout)
{
String entry_str = entry.toString();
String log_node_name;
/** Wait for entries from `log` directory (a common log, from where replicas copy entries to their queue) to be processed.
*
* The problem is that the numbers (`sequential` node) of the queue elements in `log` and in `queue` do not match.
* (And the numbers of the same log element for different replicas do not match in the `queue`.)
*/
/** First, you need to wait until replica takes `queue` element from the `log` to its queue,
* if it has not been done already (see the `pullLogsToQueue` function).
*
* To do this, check its node `log_pointer` - the maximum number of the element taken from `log` + 1.
*/
bool waiting_itself = replica == replica_name;
/// Do not wait if timeout is zero
bool wait_for_inactive = wait_for_inactive_timeout != 0;
/// Wait for unlimited time if timeout is negative
bool check_timeout = wait_for_inactive_timeout > 0;
Stopwatch time_waiting;
const auto & stop_waiting = [&]()
{
bool stop_waiting_itself = waiting_itself && (partial_shutdown_called || shutdown_prepared_called || shutdown_called);
bool timeout_exceeded = check_timeout && wait_for_inactive_timeout < time_waiting.elapsedSeconds();
bool stop_waiting_inactive = (!wait_for_inactive || timeout_exceeded)
&& !getZooKeeper()->exists(fs::path(table_zookeeper_path) / "replicas" / replica / "is_active");
return is_dropped || stop_waiting_itself || stop_waiting_inactive;
};
/// Don't recheck ZooKeeper too often
constexpr auto event_wait_timeout_ms = 3000;
LOG_DEBUG(log, "Waiting for {} to process log entry", replica);
if (startsWith(entry.znode_name, "log-"))
{
/// Take the number from the node name `log-xxxxxxxxxx`.
UInt64 log_index = parse<UInt64>(entry.znode_name.substr(entry.znode_name.size() - 10));
log_node_name = entry.znode_name;
LOG_DEBUG(log, "Waiting for {} to pull {} to queue", replica, log_node_name);
/// Let's wait until entry gets into the replica queue.
bool pulled_to_queue = false;
do
{
zkutil::EventPtr event = std::make_shared<Poco::Event>();
String log_pointer = getZooKeeper()->get(fs::path(table_zookeeper_path) / "replicas" / replica / "log_pointer", nullptr, event);
if (!log_pointer.empty() && parse<UInt64>(log_pointer) > log_index)
{
pulled_to_queue = true;
break;
}
/// Wait with timeout because we can be already shut down, but not dropped.
/// So log_pointer node will exist, but we will never update it because all background threads already stopped.
/// It can lead to query hung because table drop query can wait for some query (alter, optimize, etc) which called this method,
/// but the query will never finish because the drop already shut down the table.
if (!stop_waiting())
event->tryWait(event_wait_timeout_ms);
} while (!stop_waiting());
if (!pulled_to_queue)
return false;
LOG_DEBUG(log, "Looking for node corresponding to {} in {} queue", log_node_name, replica);
}
else if (!entry.log_entry_id.empty())
{
/// First pass, check the table log.
/// If found in the log, wait for replica to fetch it to the queue.
/// If not found in the log, it is already in the queue.
LOG_DEBUG(log, "Looking for log entry with id `{}` in the log", entry.log_entry_id);
String log_pointer = getZooKeeper()->get(fs::path(table_zookeeper_path) / "replicas" / replica / "log_pointer");
Strings log_entries = getZooKeeper()->getChildren(fs::path(table_zookeeper_path) / "log");
UInt64 log_index = 0;
bool found = false;
for (const String & log_entry_name : log_entries)
{
log_index = parse<UInt64>(log_entry_name.substr(log_entry_name.size() - 10));
if (!log_pointer.empty() && log_index < parse<UInt64>(log_pointer))
continue;
String log_entry_str;
Coordination::Stat log_entry_stat;
bool exists = getZooKeeper()->tryGet(fs::path(table_zookeeper_path) / "log" / log_entry_name, log_entry_str, &log_entry_stat);
ReplicatedMergeTreeLogEntryData log_entry = *ReplicatedMergeTreeLogEntry::parse(log_entry_str, log_entry_stat, format_version);
if (exists && entry.log_entry_id == log_entry.log_entry_id)
{
LOG_DEBUG(log, "Found log entry with id `{}` in the log", entry.log_entry_id);
found = true;
log_node_name = log_entry_name;
break;
}
}
if (found)
{
LOG_DEBUG(log, "Waiting for {} to pull {} to queue", replica, log_node_name);
/// Let's wait until entry gets into the replica queue.
bool pulled_to_queue = false;
do
{
zkutil::EventPtr event = std::make_shared<Poco::Event>();
log_pointer = getZooKeeper()->get(fs::path(table_zookeeper_path) / "replicas" / replica / "log_pointer", nullptr, event);
if (!log_pointer.empty() && parse<UInt64>(log_pointer) > log_index)
{
pulled_to_queue = true;
break;
}
/// Wait with timeout because we can be already shut down, but not dropped.
/// So log_pointer node will exist, but we will never update it because all background threads already stopped.
/// It can lead to query hung because table drop query can wait for some query (alter, optimize, etc) which called this method,
/// but the query will never finish because the drop already shut down the table.
if (!stop_waiting())
event->tryWait(event_wait_timeout_ms);
} while (!stop_waiting());
if (!pulled_to_queue)
return false;
}
}
else
{
throw Exception(ErrorCodes::LOGICAL_ERROR, "Logical error: unexpected name of log node: {}", entry.znode_name);
}
/** Second - find the corresponding entry in the queue of the specified replica.
* Its number may not match the `log` node. Therefore, we search by comparing the content.
*/
Strings queue_entries = getZooKeeper()->getChildren(fs::path(table_zookeeper_path) / "replicas" / replica / "queue");
String queue_entry_to_wait_for;
for (const String & entry_name : queue_entries)
{
String queue_entry_str;
Coordination::Stat queue_entry_stat;
bool exists = getZooKeeper()->tryGet(fs::path(table_zookeeper_path) / "replicas" / replica / "queue" / entry_name, queue_entry_str, &queue_entry_stat);
if (exists && queue_entry_str == entry_str)
{
queue_entry_to_wait_for = entry_name;
break;
}
else if (!entry.log_entry_id.empty())
{
/// Check if the id matches rather than just contents. This entry
/// might have been written by different ClickHouse versions and
/// it is hard to guarantee same text representation.
ReplicatedMergeTreeLogEntryData queue_entry = *ReplicatedMergeTreeLogEntry::parse(queue_entry_str, queue_entry_stat, format_version);
if (entry.log_entry_id == queue_entry.log_entry_id)
{
queue_entry_to_wait_for = entry_name;
break;
}
}
}
/// While looking for the record, it has already been executed and deleted.
if (queue_entry_to_wait_for.empty())
{
LOG_DEBUG(log, "No corresponding node found. Assuming it has been already processed. Found {} nodes", queue_entries.size());
return true;
}
LOG_DEBUG(log, "Waiting for {} to disappear from {} queue", queue_entry_to_wait_for, replica);
/// Third - wait until the entry disappears from the replica queue or replica become inactive.
String path_to_wait_on = fs::path(table_zookeeper_path) / "replicas" / replica / "queue" / queue_entry_to_wait_for;
return getZooKeeper()->waitForDisappear(path_to_wait_on, stop_waiting);
}
void StorageReplicatedMergeTree::getStatus(ReplicatedTableStatus & res, bool with_zk_fields)
{
auto zookeeper = tryGetZooKeeper();
const auto storage_settings_ptr = getSettings();
res.is_leader = is_leader;
res.can_become_leader = storage_settings_ptr->replicated_can_become_leader;
res.is_readonly = is_readonly;
res.is_session_expired = !zookeeper || zookeeper->expired();
res.queue = queue.getStatus();
res.absolute_delay = getAbsoluteDelay(); /// NOTE: may be slightly inconsistent with queue status.
/// NOTE: consider convert to UInt64
res.parts_to_check = static_cast<UInt32>(part_check_thread.size());
res.zookeeper_name = zookeeper_name;
res.zookeeper_path = zookeeper_path;
res.replica_name = replica_name;
res.replica_path = replica_path;
res.columns_version = -1;
res.log_max_index = 0;
res.log_pointer = 0;
res.total_replicas = 0;
res.active_replicas = 0;
res.lost_part_count = 0;
res.last_queue_update_exception = getLastQueueUpdateException();
if (with_zk_fields && !res.is_session_expired)
{
try
{
std::vector<std::string> paths;
paths.push_back(fs::path(zookeeper_path) / "log");
paths.push_back(fs::path(zookeeper_path) / "replicas");
auto children_result = zookeeper->getChildren(paths);
const auto & log_entries = children_result[0].names;
const auto & all_replicas = children_result[1].names;
paths.clear();
paths.push_back(fs::path(replica_path) / "log_pointer");
paths.push_back(fs::path(zookeeper_path) / "lost_part_count");
for (const String & replica : all_replicas)
paths.push_back(fs::path(zookeeper_path) / "replicas" / replica / "is_active");
auto get_result = zookeeper->tryGet(paths);
const auto & log_pointer_str = get_result[0].data;
if (get_result[0].error == Coordination::Error::ZNONODE)
throw zkutil::KeeperException(get_result[0].error);
if (!log_entries.empty())
{
const String & last_log_entry = *std::max_element(log_entries.begin(), log_entries.end());
res.log_max_index = parse<UInt64>(last_log_entry.substr(strlen("log-")));
}
res.log_pointer = log_pointer_str.empty() ? 0 : parse<UInt64>(log_pointer_str);
res.total_replicas = all_replicas.size();
if (get_result[1].error == Coordination::Error::ZNONODE)
res.lost_part_count = 0;
else
res.lost_part_count = get_result[1].data.empty() ? 0 : parse<UInt64>(get_result[1].data);
for (size_t i = 0, size = all_replicas.size(); i < size; ++i)
{
bool is_replica_active = get_result[i + 2].error != Coordination::Error::ZNONODE;
res.active_replicas += static_cast<UInt8>(is_replica_active);
res.replica_is_active.emplace(all_replicas[i], is_replica_active);
}
}
catch (const Coordination::Exception &)
{
res.zookeeper_exception = getCurrentExceptionMessage(false);
}
}
}
void StorageReplicatedMergeTree::getQueue(LogEntriesData & res, String & replica_name_)
{
replica_name_ = replica_name;
queue.getEntries(res);
}
std::vector<PartMovesBetweenShardsOrchestrator::Entry> StorageReplicatedMergeTree::getPartMovesBetweenShardsEntries()
{
return part_moves_between_shards_orchestrator.getEntries();
}
time_t StorageReplicatedMergeTree::getAbsoluteDelay() const
{
time_t min_unprocessed_insert_time = 0;
time_t max_processed_insert_time = 0;
queue.getInsertTimes(min_unprocessed_insert_time, max_processed_insert_time);
/// Load start time, then finish time to avoid reporting false delay when start time is updated
/// between loading of two variables.
time_t queue_update_start_time = last_queue_update_start_time.load();
time_t queue_update_finish_time = last_queue_update_finish_time.load();
time_t current_time = time(nullptr);
if (!queue_update_finish_time)
{
/// We have not updated queue even once yet (perhaps replica is readonly).
/// As we have no info about the current state of replication log, return effectively infinite delay.
return current_time;
}
else if (min_unprocessed_insert_time)
{
/// There are some unprocessed insert entries in queue.
return (current_time > min_unprocessed_insert_time) ? (current_time - min_unprocessed_insert_time) : 0;
}
else if (queue_update_start_time > queue_update_finish_time)
{
/// Queue is empty, but there are some in-flight or failed queue update attempts
/// (likely because of problems with connecting to ZooKeeper).
/// Return the time passed since last attempt.
return (current_time > queue_update_start_time) ? (current_time - queue_update_start_time) : 0;
}
else
{
/// Everything is up-to-date.
return 0;
}
}
void StorageReplicatedMergeTree::getReplicaDelays(time_t & out_absolute_delay, time_t & out_relative_delay)
{
assertNotReadonly();
time_t current_time = time(nullptr);
out_absolute_delay = getAbsoluteDelay();
out_relative_delay = 0;
const auto storage_settings_ptr = getSettings();
/** Relative delay is the maximum difference of absolute delay from any other replica,
* (if this replica lags behind any other live replica, or zero, otherwise).
* Calculated only if the absolute delay is large enough.
*/
if (out_absolute_delay < static_cast<time_t>(storage_settings_ptr->min_relative_delay_to_measure))
return;
auto zookeeper = getZooKeeper();
time_t max_replicas_unprocessed_insert_time = 0;
bool have_replica_with_nothing_unprocessed = false;
Strings replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
for (const auto & replica : replicas)
{
if (replica == replica_name)
continue;
/// Skip dead replicas.
if (!zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active"))
continue;
String value;
if (!zookeeper->tryGet(fs::path(zookeeper_path) / "replicas" / replica / "min_unprocessed_insert_time", value))
continue;
time_t replica_time = value.empty() ? 0 : parse<time_t>(value);
if (replica_time == 0)
{
/** Note
* The conclusion that the replica does not lag may be incorrect,
* because the information about `min_unprocessed_insert_time` is taken
* only from that part of the log that has been moved to the queue.
* If the replica for some reason has stalled `queueUpdatingTask`,
* then `min_unprocessed_insert_time` will be incorrect.
*/
have_replica_with_nothing_unprocessed = true;
break;
}
if (replica_time > max_replicas_unprocessed_insert_time)
max_replicas_unprocessed_insert_time = replica_time;
}
if (have_replica_with_nothing_unprocessed)
out_relative_delay = out_absolute_delay;
else
{
max_replicas_unprocessed_insert_time = std::min(current_time, max_replicas_unprocessed_insert_time);
time_t min_replicas_delay = current_time - max_replicas_unprocessed_insert_time;
if (out_absolute_delay > min_replicas_delay)
out_relative_delay = out_absolute_delay - min_replicas_delay;
}
}
void StorageReplicatedMergeTree::fetchPartition(
const ASTPtr & partition,
const StorageMetadataPtr & metadata_snapshot,
const String & from_,
bool fetch_part,
ContextPtr query_context)
{
Macros::MacroExpansionInfo info;
info.expand_special_macros_only = false;
info.table_id = getStorageID();
info.table_id.uuid = UUIDHelpers::Nil;
auto expand_from = query_context->getMacros()->expand(from_, info);
String from_zookeeper_name = zkutil::extractZooKeeperName(expand_from);
String from = zkutil::extractZooKeeperPath(expand_from, /* check_starts_with_slash */ true);
if (from.empty())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "ZooKeeper path should not be empty");
zkutil::ZooKeeperPtr zookeeper;
if (from_zookeeper_name != default_zookeeper_name)
zookeeper = getContext()->getAuxiliaryZooKeeper(from_zookeeper_name);
else
zookeeper = getZooKeeper();
if (from.back() == '/')
from.resize(from.size() - 1);
if (fetch_part)
{
String part_name = partition->as<ASTLiteral &>().value.safeGet<String>();
auto part_path = findReplicaHavingPart(part_name, from, zookeeper);
if (part_path.empty())
throw Exception(ErrorCodes::NO_REPLICA_HAS_PART, "Part {} does not exist on any replica", part_name);
/** Let's check that there is no such part in the `detached` directory (where we will write the downloaded parts).
* Unreliable (there is a race condition) - such a part may appear a little later.
*/
if (checkIfDetachedPartExists(part_name))
throw Exception(ErrorCodes::DUPLICATE_DATA_PART, "Detached part {} already exists.", part_name);
LOG_INFO(log, "Will fetch part {} from shard {}", part_name, from_);
try
{
/// part name, metadata, part_path, true, 0, zookeeper
if (!fetchPart(part_name, metadata_snapshot, from_zookeeper_name, part_path, true, 0, zookeeper, /* try_fetch_shared = */ false))
throw Exception(ErrorCodes::UNFINISHED, "Failed to fetch part {} from {}", part_name, from_);
}
catch (const DB::Exception & e)
{
if (e.code() != ErrorCodes::RECEIVED_ERROR_FROM_REMOTE_IO_SERVER && e.code() != ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS
&& e.code() != ErrorCodes::CANNOT_READ_ALL_DATA)
throw;
LOG_INFO(log, getExceptionMessageAndPattern(e, /* with_stacktrace */ false));
}
return;
}
String partition_id = getPartitionIDFromQuery(partition, query_context);
LOG_INFO(log, "Will fetch partition {} from shard {}", partition_id, from_);
/** Let's check that there is no such partition in the `detached` directory (where we will write the downloaded parts).
* Unreliable (there is a race condition) - such a partition may appear a little later.
*/
if (checkIfDetachedPartitionExists(partition_id))
throw Exception(ErrorCodes::PARTITION_ALREADY_EXISTS, "Detached partition {} already exists.", partition_id);
zkutil::Strings replicas;
zkutil::Strings active_replicas;
String best_replica;
{
/// List of replicas of source shard.
replicas = zookeeper->getChildren(fs::path(from) / "replicas");
/// Leave only active replicas.
active_replicas.reserve(replicas.size());
for (const String & replica : replicas)
if (zookeeper->exists(fs::path(from) / "replicas" / replica / "is_active"))
active_replicas.push_back(replica);
if (active_replicas.empty())
throw Exception(ErrorCodes::NO_ACTIVE_REPLICAS, "No active replicas for shard {}", from_);
/** You must select the best (most relevant) replica.
* This is a replica with the maximum `log_pointer`, then with the minimum `queue` size.
* NOTE This is not exactly the best criteria. It does not make sense to download old partitions,
* and it would be nice to be able to choose the replica closest by network.
* NOTE Of course, there are data races here. You can solve it by retrying.
*/
Int64 max_log_pointer = -1;
UInt64 min_queue_size = std::numeric_limits<UInt64>::max();
for (const String & replica : active_replicas)
{
String current_replica_path = fs::path(from) / "replicas" / replica;
String log_pointer_str = zookeeper->get(fs::path(current_replica_path) / "log_pointer");
Int64 log_pointer = log_pointer_str.empty() ? 0 : parse<UInt64>(log_pointer_str);
Coordination::Stat stat;
zookeeper->get(fs::path(current_replica_path) / "queue", &stat);
size_t queue_size = stat.numChildren;
if (log_pointer > max_log_pointer
|| (log_pointer == max_log_pointer && queue_size < min_queue_size))
{
max_log_pointer = log_pointer;
min_queue_size = queue_size;
best_replica = replica;
}
}
}
if (best_replica.empty())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Logical error: cannot choose best replica.");
LOG_INFO(log, "Found {} replicas, {} of them are active. Selected {} to fetch from.", replicas.size(), active_replicas.size(), best_replica);
String best_replica_path = fs::path(from) / "replicas" / best_replica;
/// Let's find out which parts are on the best replica.
/** Trying to download these parts.
* Some of them could be deleted due to the merge.
* In this case, update the information about the available parts and try again.
*/
unsigned try_no = 0;
Strings missing_parts;
do
{
if (try_no)
LOG_INFO(log, "Some of parts ({}) are missing. Will try to fetch covering parts.", missing_parts.size());
if (try_no >= query_context->getSettings().max_fetch_partition_retries_count)
throw Exception(ErrorCodes::TOO_MANY_RETRIES_TO_FETCH_PARTS,
"Too many retries to fetch parts from {}:{}", from_zookeeper_name, best_replica_path);
Strings parts = zookeeper->getChildren(fs::path(best_replica_path) / "parts");
ActiveDataPartSet active_parts_set(format_version, parts);
Strings parts_to_fetch;
if (missing_parts.empty())
{
parts_to_fetch = active_parts_set.getParts();
/// Leaving only the parts of the desired partition.
Strings parts_to_fetch_partition;
for (const String & part : parts_to_fetch)
{
if (MergeTreePartInfo::fromPartName(part, format_version).partition_id == partition_id)
parts_to_fetch_partition.push_back(part);
}
parts_to_fetch = std::move(parts_to_fetch_partition);
if (parts_to_fetch.empty())
throw Exception(ErrorCodes::PARTITION_DOESNT_EXIST,
"Partition {} on {}:{} doesn't exist", partition_id, from_zookeeper_name, best_replica_path);
}
else
{
for (const String & missing_part : missing_parts)
{
String containing_part = active_parts_set.getContainingPart(missing_part);
if (!containing_part.empty())
parts_to_fetch.push_back(containing_part);
else
LOG_WARNING(log, "Part {} on replica {}:{} has been vanished.", missing_part, from_zookeeper_name, best_replica_path);
}
}
LOG_INFO(log, "Parts to fetch: {}", parts_to_fetch.size());
missing_parts.clear();
for (const String & part : parts_to_fetch)
{
bool fetched = false;
try
{
fetched = fetchPart(part, metadata_snapshot, from_zookeeper_name, best_replica_path, true, 0, zookeeper, /* try_fetch_shared = */ false);
}
catch (const DB::Exception & e)
{
if (e.code() != ErrorCodes::RECEIVED_ERROR_FROM_REMOTE_IO_SERVER && e.code() != ErrorCodes::RECEIVED_ERROR_TOO_MANY_REQUESTS
&& e.code() != ErrorCodes::CANNOT_READ_ALL_DATA)
throw;
LOG_INFO(log, getExceptionMessageAndPattern(e, /* with_stacktrace */ false));
}
if (!fetched)
missing_parts.push_back(part);
}
++try_no;
} while (!missing_parts.empty());
}
void StorageReplicatedMergeTree::mutate(const MutationCommands & commands, ContextPtr query_context)
{
/// Overview of the mutation algorithm.
///
/// When the client executes a mutation, this method is called. It acquires block numbers in all
/// partitions, saves them in the mutation entry and writes the mutation entry to a new ZK node in
/// the /mutations folder. This block numbers are needed to determine which parts should be mutated and
/// which shouldn't (parts inserted after the mutation will have the block number higher than the
/// block number acquired by the mutation in that partition and so will not be mutated).
/// This block number is called "mutation version" in that partition.
///
/// Mutation versions are acquired atomically in all partitions, so the case when an insert in some
/// partition has the block number higher than the mutation version but the following insert into another
/// partition acquires the block number lower than the mutation version in that partition is impossible.
/// Another important invariant: mutation entries appear in /mutations in the order of their mutation
/// versions (in any partition). This means that mutations form a sequence and we can execute them in
/// the order of their mutation versions and not worry that some mutation with the smaller version
/// will suddenly appear.
///
/// During mutations individual parts are immutable - when we want to change the contents of a part
/// we prepare the new part and add it to MergeTreeData (the original part gets replaced). The fact that
/// we have mutated the part is recorded in the part->info.mutation field of MergeTreePartInfo.
/// The relation with the original part is preserved because the new part covers the same block range
/// as the original one.
///
/// We then can for each part determine its "mutation version": the version of the last mutation in
/// the mutation sequence that we regard as already applied to that part. All mutations with the greater
/// version number will still need to be applied to that part.
///
/// Execution of mutations is done asynchronously. All replicas watch the /mutations directory and
/// load new mutation entries as they appear (see mutationsUpdatingTask()). Next we need to determine
/// how to mutate individual parts consistently with part merges. This is done by the leader replica
/// (see mergeSelectingTask() and class ReplicatedMergeTreeMergePredicate for details). Important
/// invariants here are that a) all source parts for a single merge must have the same mutation version
/// and b) any part can be mutated only once or merged only once (e.g. once we have decided to mutate
/// a part then we need to execute that mutation and can assign merges only to the new part and not to the
/// original part). Multiple consecutive mutations can be executed at once (without writing the
/// intermediate result to a part).
///
/// Leader replica records its decisions to the replication log (/log directory in ZK) in the form of
/// MUTATE_PART entries and all replicas then execute them in the background pool
/// (see MutateTask class). When a replica encounters a MUTATE_PART command, it is
/// guaranteed that the corresponding mutation entry is already loaded (when we pull entries from
/// replication log into the replica queue, we also load mutation entries). Note that just as with merges
/// the replica can decide not to do the mutation locally and fetch the mutated part from another replica
/// instead.
///
/// Mutations of individual parts are in fact pretty similar to merges, e.g. their assignment and execution
/// is governed by the same storage_settings. TODO: support a single "merge-mutation" operation when the data
/// read from the the source parts is first mutated on the fly to some uniform mutation version and then
/// merged to a resulting part.
///
/// After all needed parts are mutated (i.e. all active parts have the mutation version greater than
/// the version of this mutation), the mutation is considered done and can be deleted.
delayMutationOrThrowIfNeeded(&partial_shutdown_event, query_context);
ReplicatedMergeTreeMutationEntry mutation_entry;
mutation_entry.source_replica = replica_name;
mutation_entry.commands = commands;
const String mutations_path = fs::path(zookeeper_path) / "mutations";
const auto zookeeper = getZooKeeper();
/// Update the mutations_path node when creating the mutation and check its version to ensure that
/// nodes for mutations are created in the same order as the corresponding block numbers.
/// Should work well if the number of concurrent mutation requests is small.
while (true)
{
Coordination::Stat mutations_stat;
zookeeper->get(mutations_path, &mutations_stat);
PartitionBlockNumbersHolder partition_block_numbers_holder =
allocateBlockNumbersInAffectedPartitions(mutation_entry.commands, query_context, zookeeper);
mutation_entry.block_numbers = partition_block_numbers_holder.getBlockNumbers();
mutation_entry.create_time = time(nullptr);
/// The following version check guarantees the linearizability property for any pair of mutations:
/// mutation with higher sequence number is guaranteed to have higher block numbers in every partition
/// (and thus will be applied strictly according to sequence numbers of mutations)
Coordination::Requests requests;
requests.emplace_back(zkutil::makeSetRequest(mutations_path, String(), mutations_stat.version));
requests.emplace_back(zkutil::makeCreateRequest(
fs::path(mutations_path) / "", mutation_entry.toString(), zkutil::CreateMode::PersistentSequential));
if (auto txn = query_context->getZooKeeperMetadataTransaction())
txn->moveOpsTo(requests);
Coordination::Responses responses;
Coordination::Error rc = zookeeper->tryMulti(requests, responses);
partition_block_numbers_holder.reset();
if (rc == Coordination::Error::ZOK)
{
const String & path_created =
dynamic_cast<const Coordination::CreateResponse *>(responses[1].get())->path_created;
mutation_entry.znode_name = path_created.substr(path_created.find_last_of('/') + 1);
LOG_TRACE(log, "Created mutation with ID {} (data versions: {})",
mutation_entry.znode_name, mutation_entry.getBlockNumbersForLogs());
break;
}
else if (rc == Coordination::Error::ZBADVERSION)
{
/// Cannot retry automatically, because some zookeeper ops were lost on the first attempt. Will retry on DDLWorker-level.
if (query_context->getZooKeeperMetadataTransaction())
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot execute alter, because mutations version was suddenly changed due "
"to concurrent alter");
LOG_TRACE(log, "Version conflict when trying to create a mutation node, retrying...");
continue;
}
else
throw Coordination::Exception::fromMessage(rc, "Unable to create a mutation znode");
}
merge_selecting_task->schedule();
waitMutation(mutation_entry.znode_name, query_context->getSettingsRef().mutations_sync);
}
void StorageReplicatedMergeTree::waitMutation(const String & znode_name, size_t mutations_sync) const
{
if (!mutations_sync)
return;
/// we have to wait
auto zookeeper = getZooKeeper();
Strings replicas;
if (mutations_sync == 2) /// wait for all replicas
{
replicas = zookeeper->getChildren(fs::path(zookeeper_path) / "replicas");
/// This replica should be first, to ensure that the mutation will be loaded into memory
for (auto it = replicas.begin(); it != replicas.end(); ++it)
{
if (*it == replica_name)
{
std::iter_swap(it, replicas.begin());
break;
}
}
}
else if (mutations_sync == 1) /// just wait for ourself
replicas.push_back(replica_name);
waitMutationToFinishOnReplicas(replicas, znode_name);
}
std::vector<MergeTreeMutationStatus> StorageReplicatedMergeTree::getMutationsStatus() const
{
return queue.getMutationsStatus();
}
CancellationCode StorageReplicatedMergeTree::killMutation(const String & mutation_id)
{
assertNotReadonly();
zkutil::ZooKeeperPtr zookeeper = getZooKeeperAndAssertNotReadonly();
LOG_INFO(log, "Killing mutation {}", mutation_id);
auto mutation_entry = queue.removeMutation(zookeeper, mutation_id);
if (!mutation_entry)
return CancellationCode::NotFound;
/// After this point no new part mutations will start and part mutations that still exist
/// in the queue will be skipped.
/// Cancel already running part mutations.
for (const auto & pair : mutation_entry->block_numbers)
{
const String & partition_id = pair.first;
Int64 block_number = pair.second;
getContext()->getMergeList().cancelPartMutations(getStorageID(), partition_id, block_number);
}
return CancellationCode::CancelSent;
}
bool StorageReplicatedMergeTree::hasLightweightDeletedMask() const
{
return has_lightweight_delete_parts.load(std::memory_order_relaxed);
}
size_t StorageReplicatedMergeTree::clearOldPartsAndRemoveFromZK()
{
auto table_lock = lockForShare(RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
auto zookeeper = getZooKeeper();
/// Now these parts are in Deleting state. If we fail to remove some of them we must roll them back to Outdated state.
/// Otherwise they will not be deleted.
DataPartsVector parts = grabOldParts();
size_t total_parts_to_remove = parts.size();
if (parts.empty())
return total_parts_to_remove;
NOEXCEPT_SCOPE({ clearOldPartsAndRemoveFromZKImpl(zookeeper, std::move(parts)); });
return total_parts_to_remove;
}
void StorageReplicatedMergeTree::clearOldPartsAndRemoveFromZKImpl(zkutil::ZooKeeperPtr zookeeper, DataPartsVector && parts)
{
DataPartsVector parts_to_delete_only_from_filesystem; // Only duplicates
DataPartsVector parts_to_delete_completely; // All parts except duplicates
DataPartsVector parts_to_retry_deletion; // Parts that should be retried due to network problems
DataPartsVector parts_to_remove_from_filesystem; // Parts removed from ZK
for (const auto & part : parts)
{
/// Broken part can be removed from zk by removePartAndEnqueueFetch(...) only.
/// Removal without enqueueing a fetch leads to intersecting parts.
if (part->is_duplicate || part->is_unexpected_local_part)
{
LOG_WARNING(log, "Will not remove part {} from ZooKeeper (is_duplicate: {}, is_unexpected_local_part: {})",
part->name, part->is_duplicate, part->is_unexpected_local_part);
parts_to_delete_only_from_filesystem.emplace_back(part);
}
else
parts_to_delete_completely.emplace_back(part);
}
parts.clear();
auto delete_parts_from_fs_and_rollback_in_case_of_error = [this] (const DataPartsVector & parts_to_delete, const String & parts_type)
{
NameSet parts_failed_to_delete;
clearPartsFromFilesystem(parts_to_delete, false, &parts_failed_to_delete);
DataPartsVector finally_remove_parts;
if (!parts_failed_to_delete.empty())
{
DataPartsVector rollback_parts;
for (const auto & part : parts_to_delete)
{
if (!parts_failed_to_delete.contains(part->name))
finally_remove_parts.push_back(part);
else
rollback_parts.push_back(part);
}
if (!rollback_parts.empty())
rollbackDeletingParts(rollback_parts);
}
else /// all parts were successfully removed
{
finally_remove_parts = parts_to_delete;
}
try
{
removePartsFinally(finally_remove_parts);
LOG_DEBUG(log, "Removed {} {} parts", finally_remove_parts.size(), parts_type);
}
catch (...)
{
tryLogCurrentException(log, "Failed to remove some parts from memory, or write info about them into part log");
}
};
/// Delete duplicate parts from filesystem
if (!parts_to_delete_only_from_filesystem.empty())
{
/// It can happen that some error appear during part removal from FS.
/// In case of such exception we have to change state of failed parts from Deleting to Outdated.
/// Otherwise nobody will try to remove them again (see grabOldParts).
delete_parts_from_fs_and_rollback_in_case_of_error(parts_to_delete_only_from_filesystem, "old duplicate");
}
/// Delete normal parts from ZooKeeper
NameSet part_names_to_retry_deletion;
try
{
Strings part_names_to_delete_completely;
for (const auto & part : parts_to_delete_completely)
part_names_to_delete_completely.emplace_back(part->name);
LOG_DEBUG(log, "Removing {} old parts from ZooKeeper", parts_to_delete_completely.size());
removePartsFromZooKeeper(zookeeper, part_names_to_delete_completely, &part_names_to_retry_deletion);
}
catch (...)
{
LOG_ERROR(log, "There is a problem with deleting parts from ZooKeeper: {}", getCurrentExceptionMessage(true));
}
/// Part names that were reliably deleted from ZooKeeper should be deleted from filesystem
auto num_reliably_deleted_parts = parts_to_delete_completely.size() - part_names_to_retry_deletion.size();
LOG_DEBUG(log, "Removed {} old parts from ZooKeeper. Removing them from filesystem.", num_reliably_deleted_parts);
/// Delete normal parts on two sets
for (auto & part : parts_to_delete_completely)
{
if (!part_names_to_retry_deletion.contains(part->name))
parts_to_remove_from_filesystem.emplace_back(part);
else
parts_to_retry_deletion.emplace_back(part);
}
/// Will retry deletion
if (!parts_to_retry_deletion.empty())
{
rollbackDeletingParts(parts_to_retry_deletion);
LOG_DEBUG(log, "Will retry deletion of {} parts in the next time", parts_to_retry_deletion.size());
}
/// Remove parts from filesystem and finally from data_parts
if (!parts_to_remove_from_filesystem.empty())
{
/// It can happen that some error appear during part removal from FS.
/// In case of such exception we have to change state of failed parts from Deleting to Outdated.
/// Otherwise nobody will try to remove them again (see grabOldParts).
delete_parts_from_fs_and_rollback_in_case_of_error(parts_to_remove_from_filesystem, "old");
}
}
void StorageReplicatedMergeTree::forcefullyRemoveBrokenOutdatedPartFromZooKeeperBeforeDetaching(const String & part_name)
{
/// An outdated part is broken and we are going to move it do detached/
/// But we need to remove it from ZooKeeper as well. Otherwise it will be considered as "lost forever".
/// Since the part is Outdated, it should be safe to remove it, but it's still dangerous.
/// It could became Outdated because it was merged/mutated (so we have a covering part) or because it was dropped.
/// But DROP [PART]ITION waits for all Outdated parts to be loaded, so it's not the case.
auto zookeeper = getZooKeeper();
String part_path = replica_path + "/parts/" + part_name;
if (!zookeeper->exists(part_path))
return;
auto part = getActiveContainingPart(part_name);
if (!part)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Outdated part {} is broken and going to be detached, "
"but there's no active covering part, so we are not sure that it can be safely removed from ZooKeeper "
"(path: {})", part_name, part_path);
LOG_WARNING(log, "Outdated part {} is broken and going to be detached, removing it from ZooKeeper. The part is covered by {}",
part_name, part->name);
removePartsFromZooKeeperWithRetries({part_name}, /* infinite retries */ 0);
}
void StorageReplicatedMergeTree::removePartsFromZooKeeperWithRetries(PartsToRemoveFromZooKeeper & parts, size_t max_retries)
{
Strings part_names_to_remove;
for (const auto & part : parts)
part_names_to_remove.emplace_back(part.getPartName());
return removePartsFromZooKeeperWithRetries(part_names_to_remove, max_retries);
}
void StorageReplicatedMergeTree::removePartsFromZooKeeperWithRetries(const Strings & part_names, size_t max_retries)
{
auto zookeeper = getZooKeeper();
NameSet parts_to_retry_set;
removePartsFromZooKeeper(zookeeper, part_names, &parts_to_retry_set);
size_t num_tries = 0;
while (!parts_to_retry_set.empty() && (max_retries == 0 || num_tries < max_retries))
{
zookeeper = getZooKeeper();
Strings parts_to_retry;
std::move(parts_to_retry_set.begin(), parts_to_retry_set.end(), std::back_inserter(parts_to_retry));
parts_to_retry_set.clear();
removePartsFromZooKeeper(zookeeper, parts_to_retry, &parts_to_retry_set);
++num_tries;
}
if (!parts_to_retry_set.empty())
throw Exception(ErrorCodes::UNFINISHED, "Failed to remove {} parts from ZooKeeper after {} retries", parts_to_retry_set.size(), num_tries);
}
void StorageReplicatedMergeTree::removePartsFromZooKeeper(
zkutil::ZooKeeperPtr & zookeeper, const Strings & part_names, NameSet * parts_should_be_retried)
try
{
Strings exists_paths;
std::vector<std::future<Coordination::MultiResponse>> remove_futures;
exists_paths.reserve(part_names.size());
remove_futures.reserve(part_names.size());
/// Exception can be thrown from loop
/// if zk session will be dropped
for (const String & part_name : part_names)
{
exists_paths.emplace_back(fs::path(replica_path) / "parts" / part_name);
}
auto exists_results = zookeeper->exists(exists_paths);
for (size_t i = 0; i < part_names.size(); ++i)
{
auto exists_resp = exists_results[i];
if (exists_resp.error == Coordination::Error::ZOK)
{
Coordination::Requests ops;
getRemovePartFromZooKeeperOps(part_names[i], ops, exists_resp.stat.numChildren > 0);
remove_futures.emplace_back(zookeeper->asyncTryMultiNoThrow(ops));
}
else
{
LOG_DEBUG(log, "There is no part {} in ZooKeeper, it was only in filesystem", part_names[i]);
// emplace invalid future so that the total number of futures is the same as part_names.size();
remove_futures.emplace_back();
}
}
for (size_t i = 0; i < remove_futures.size(); ++i)
{
auto & future = remove_futures[i];
if (!future.valid())
continue;
auto response = future.get();
if (response.error == Coordination::Error::ZOK)
continue;
if (response.error == Coordination::Error::ZNONODE)
{
LOG_DEBUG(log, "There is no part {} in ZooKeeper, it was only in filesystem", part_names[i]);
}
else
{
if (parts_should_be_retried)
parts_should_be_retried->insert(part_names[i]);
if (!Coordination::isHardwareError(response.error))
LOG_WARNING(log, "Cannot remove part {} from ZooKeeper: {}", part_names[i], Coordination::errorMessage(response.error));
}
}
}
catch (...)
{
if (parts_should_be_retried)
parts_should_be_retried->insert(part_names.begin(), part_names.end());
throw;
}
void StorageReplicatedMergeTree::clearLockedBlockNumbersInPartition(
zkutil::ZooKeeper & zookeeper, const String & partition_id, Int64 min_block_num, Int64 max_block_num)
{
/// Imagine that some INSERT query has allocated block number 42, but it's still in progress.
/// Some DROP PARTITION query gets block number 43 and commits DROP_RANGE all_0_42_999_999.
/// And after that INSERT commits GET_PART all_42_42_0. Oops, intersecting parts.
/// So we have to either wait for unfinished INSERTs or cancel them.
/// It's totally fine to cancel since we are going to remove data anyway.
/// We can safely cancel INSERT query by removing its ephemeral block number.
/// Usually it's bad idea to remove ephemeral nodes owned by someone else,
/// but INSERTs remove such nodes atomically with part commit, so INSERT will fail if node does not exist.
fs::path partition_path = fs::path(zookeeper_path) / "block_numbers" / partition_id;
Strings queries_in_progress = zookeeper.getChildren(partition_path);
if (queries_in_progress.empty())
return;
Strings paths_to_get;
for (const auto & block : queries_in_progress)
{
if (!startsWith(block, "block-"))
continue;
Int64 block_number = parse<Int64>(block.substr(strlen("block-")));
if (min_block_num <= block_number && block_number <= max_block_num)
paths_to_get.push_back(partition_path / block);
}
auto results = zookeeper.tryGet(paths_to_get);
for (size_t i = 0; i < paths_to_get.size(); ++i)
{
auto & result = results[i];
/// The query already finished
if (result.error == Coordination::Error::ZNONODE)
continue;
/// The query is not an insert (it does not have block_id)
if (result.data.ends_with(EphemeralLockInZooKeeper::LEGACY_LOCK_OTHER))
continue;
if (result.data.ends_with(EphemeralLockInZooKeeper::LEGACY_LOCK_INSERT))
{
/// Remove block number, so insert will fail to commit (it will try to remove this node too)
LOG_WARNING(log, "Some query is trying to concurrently insert block {}, will cancel it", paths_to_get[i]);
zookeeper.tryRemove(paths_to_get[i]);
}
else
{
constexpr const char * old_version_warning = "Ephemeral lock {} (referencing {}) is created by a replica "
"that running old version of ClickHouse (< 22.11). Cannot remove it, will wait for this lock to disappear. "
"Upgrade remaining hosts in the cluster to address this warning.";
constexpr const char * new_version_warning = "Ephemeral lock {} has unexpected content ({}), "
"probably it is created by a replica that running newer version of ClickHouse. "
"Cannot remove it, will wait for this lock to disappear. Upgrade remaining hosts in the cluster to address this warning.";
if (result.data.starts_with(zookeeper_path + EphemeralLockInZooKeeper::LEGACY_LOCK_PREFIX))
LOG_WARNING(log, old_version_warning, paths_to_get[i], result.data);
else
LOG_WARNING(log, new_version_warning, paths_to_get[i], result.data);
Stopwatch time_waiting;
const auto & stop_waiting = [this, &time_waiting]()
{
auto timeout = getContext()->getSettingsRef().lock_acquire_timeout.value.seconds();
return partial_shutdown_called || (timeout < time_waiting.elapsedSeconds());
};
zookeeper.waitForDisappear(paths_to_get[i], stop_waiting);
}
}
}
void StorageReplicatedMergeTree::getClearBlocksInPartitionOps(
Coordination::Requests & ops, zkutil::ZooKeeper & zookeeper, const String & partition_id, Int64 min_block_num, Int64 max_block_num)
{
getClearBlocksInPartitionOpsImpl(ops, zookeeper, partition_id, min_block_num, max_block_num, "blocks");
getClearBlocksInPartitionOpsImpl(ops, zookeeper, partition_id, min_block_num, max_block_num, "async_blocks");
}
void StorageReplicatedMergeTree::getClearBlocksInPartitionOpsImpl(
Coordination::Requests & ops, zkutil::ZooKeeper & zookeeper, const String & partition_id, Int64 min_block_num, Int64 max_block_num, const String & blocks_dir_name)
{
Strings blocks;
if (Coordination::Error::ZOK != zookeeper.tryGetChildren(fs::path(zookeeper_path) / blocks_dir_name, blocks))
throw Exception(ErrorCodes::NOT_FOUND_NODE, "Node {}/{} doesn't exist", zookeeper_path, blocks_dir_name);
String partition_prefix = partition_id + "_";
Strings paths_to_get;
for (const String & block_id : blocks)
if (startsWith(block_id, partition_prefix))
paths_to_get.push_back(fs::path(zookeeper_path) / blocks_dir_name / block_id);
auto results = zookeeper.tryGet(paths_to_get);
for (size_t i = 0; i < paths_to_get.size(); ++i)
{
const String & path = paths_to_get[i];
auto & result = results[i];
if (result.error == Coordination::Error::ZNONODE)
continue;
ReadBufferFromString buf(result.data);
const auto part_info = MergeTreePartInfo::tryParsePartName(result.data, format_version);
if (!part_info || (min_block_num <= part_info->min_block && part_info->max_block <= max_block_num))
ops.emplace_back(zkutil::makeRemoveRequest(path, -1));
}
}
void StorageReplicatedMergeTree::clearBlocksInPartition(
zkutil::ZooKeeper & zookeeper, const String & partition_id, Int64 min_block_num, Int64 max_block_num)
{
Coordination::Requests delete_requests;
getClearBlocksInPartitionOps(delete_requests, zookeeper, partition_id, min_block_num, max_block_num);
Coordination::Responses delete_responses;
auto code = zookeeper.tryMulti(delete_requests, delete_responses);
if (code != Coordination::Error::ZOK)
{
for (size_t i = 0; i < delete_requests.size(); ++i)
if (delete_responses[i]->error != Coordination::Error::ZOK)
LOG_WARNING(log, "Error while deleting ZooKeeper path `{}`: {}, ignoring.", delete_requests[i]->getPath(), delete_responses[i]->error);
}
LOG_TRACE(log, "Deleted {} deduplication block IDs in partition ID {}", delete_requests.size(), partition_id);
}
void StorageReplicatedMergeTree::replacePartitionFrom(
const StoragePtr & source_table, const ASTPtr & partition, bool replace, ContextPtr query_context)
{
/// First argument is true, because we possibly will add new data to current table.
auto lock1 = lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
auto lock2 = source_table->lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
auto storage_settings_ptr = getSettings();
auto source_metadata_snapshot = source_table->getInMemoryMetadataPtr();
auto metadata_snapshot = getInMemoryMetadataPtr();
Stopwatch watch;
ProfileEventsScope profile_events_scope;
MergeTreeData & src_data = checkStructureAndGetMergeTreeData(source_table, source_metadata_snapshot, metadata_snapshot);
String partition_id = getPartitionIDFromQuery(partition, query_context);
/// NOTE: Some covered parts may be missing in src_all_parts if corresponding log entries are not executed yet.
DataPartsVector src_all_parts = src_data.getVisibleDataPartsVectorInPartition(query_context, partition_id);
LOG_DEBUG(log, "Cloning {} parts", src_all_parts.size());
static const String TMP_PREFIX = "tmp_replace_from_";
auto zookeeper = getZooKeeper();
/// Retry if alter_partition_version changes
for (size_t retry = 0; retry < 1000; ++retry)
{
DataPartsVector src_parts;
MutableDataPartsVector dst_parts;
std::vector<scope_guard> dst_parts_locks;
Strings block_id_paths;
Strings part_checksums;
std::vector<EphemeralLockInZooKeeper> ephemeral_locks;
String alter_partition_version_path = zookeeper_path + "/alter_partition_version";
Coordination::Stat alter_partition_version_stat;
zookeeper->get(alter_partition_version_path, &alter_partition_version_stat);
/// Firstly, generate last block number and compute drop_range
/// NOTE: Even if we make ATTACH PARTITION instead of REPLACE PARTITION drop_range will not be empty, it will contain a block.
/// So, such case has special meaning, if drop_range contains only one block it means that nothing to drop.
/// TODO why not to add normal DROP_RANGE entry to replication queue if `replace` is true?
MergeTreePartInfo drop_range;
std::optional<EphemeralLockInZooKeeper> delimiting_block_lock;
bool partition_was_empty = !getFakePartCoveringAllPartsInPartition(partition_id, drop_range, delimiting_block_lock, true);
if (replace && partition_was_empty)
{
/// Nothing to drop, will just attach new parts
LOG_INFO(log, "Partition {} was empty, REPLACE PARTITION will work as ATTACH PARTITION FROM", drop_range.partition_id);
replace = false;
}
if (!replace)
{
/// It's ATTACH PARTITION FROM, not REPLACE PARTITION. We have to reset drop range
drop_range = makeDummyDropRangeForMovePartitionOrAttachPartitionFrom(partition_id);
}
assert(replace == !LogEntry::ReplaceRangeEntry::isMovePartitionOrAttachFrom(drop_range));
String drop_range_fake_part_name = getPartNamePossiblyFake(format_version, drop_range);
for (const auto & src_part : src_all_parts)
{
/// We also make some kind of deduplication to avoid duplicated parts in case of ATTACH PARTITION
/// Assume that merges in the partition are quite rare
/// Save deduplication block ids with special prefix replace_partition
if (!canReplacePartition(src_part))
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Cannot replace partition '{}' because part '{}"
"' has inconsistent granularity with table", partition_id, src_part->name);
String hash_hex = src_part->checksums.getTotalChecksumHex();
if (replace)
LOG_INFO(log, "Trying to replace {} with hash_hex {}", src_part->name, hash_hex);
else
LOG_INFO(log, "Trying to attach {} with hash_hex {}", src_part->name, hash_hex);
String block_id_path = replace ? "" : (fs::path(zookeeper_path) / "blocks" / (partition_id + "_replace_from_" + hash_hex));
auto lock = allocateBlockNumber(partition_id, zookeeper, block_id_path);
if (!lock)
{
LOG_INFO(log, "Part {} (hash {}) has been already attached", src_part->name, hash_hex);
continue;
}
UInt64 index = lock->getNumber();
MergeTreePartInfo dst_part_info(partition_id, index, index, src_part->info.level);
bool zero_copy_enabled = storage_settings_ptr->allow_remote_fs_zero_copy_replication
|| dynamic_cast<const MergeTreeData *>(source_table.get())->getSettings()->allow_remote_fs_zero_copy_replication;
IDataPartStorage::ClonePartParams clone_params
{
.copy_instead_of_hardlink = zero_copy_enabled && src_part->isStoredOnRemoteDiskWithZeroCopySupport(),
.metadata_version_to_write = metadata_snapshot->getMetadataVersion()
};
auto [dst_part, part_lock] = cloneAndLoadDataPartOnSameDisk(src_part, TMP_PREFIX, dst_part_info, metadata_snapshot, clone_params);
src_parts.emplace_back(src_part);
dst_parts.emplace_back(dst_part);
dst_parts_locks.emplace_back(std::move(part_lock));
ephemeral_locks.emplace_back(std::move(*lock));
block_id_paths.emplace_back(block_id_path);
part_checksums.emplace_back(hash_hex);
}
ReplicatedMergeTreeLogEntryData entry;
{
auto src_table_id = src_data.getStorageID();
entry.type = ReplicatedMergeTreeLogEntryData::REPLACE_RANGE;
entry.source_replica = replica_name;
entry.create_time = time(nullptr);
entry.replace_range_entry = std::make_shared<ReplicatedMergeTreeLogEntryData::ReplaceRangeEntry>();
auto & entry_replace = *entry.replace_range_entry;
entry_replace.drop_range_part_name = drop_range_fake_part_name;
entry_replace.from_database = src_table_id.database_name;
entry_replace.from_table = src_table_id.table_name;
for (const auto & part : src_parts)
entry_replace.src_part_names.emplace_back(part->name);
for (const auto & part : dst_parts)
entry_replace.new_part_names.emplace_back(part->name);
for (const String & checksum : part_checksums)
entry_replace.part_names_checksums.emplace_back(checksum);
entry_replace.columns_version = -1;
}
if (replace)
{
/// Cancel concurrent inserts in range
clearLockedBlockNumbersInPartition(*zookeeper, drop_range.partition_id, drop_range.max_block, drop_range.max_block);
/// Remove deduplication block_ids of replacing parts
clearBlocksInPartition(*zookeeper, drop_range.partition_id, drop_range.max_block, drop_range.max_block);
}
Coordination::Responses op_results;
DataPartsVector parts_holder;
try
{
Coordination::Requests ops;
for (size_t i = 0; i < dst_parts.size(); ++i)
{
getCommitPartOps(ops, dst_parts[i], block_id_paths[i]);
ephemeral_locks[i].getUnlockOp(ops);
}
if (auto txn = query_context->getZooKeeperMetadataTransaction())
txn->moveOpsTo(ops);
delimiting_block_lock->getUnlockOp(ops);
/// Check and update version to avoid race with DROP_RANGE
ops.emplace_back(zkutil::makeSetRequest(alter_partition_version_path, "", alter_partition_version_stat.version));
/// Just update version, because merges assignment relies on it
ops.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "log", "", -1));
ops.emplace_back(zkutil::makeCreateRequest(fs::path(zookeeper_path) / "log/log-", entry.toString(), zkutil::CreateMode::PersistentSequential));
Transaction transaction(*this, NO_TRANSACTION_RAW);
{
auto data_parts_lock = lockParts();
for (auto & part : dst_parts)
renameTempPartAndReplaceUnlocked(part, transaction, data_parts_lock);
}
for (const auto & dst_part : dst_parts)
lockSharedData(*dst_part, false, /*hardlinked_files*/ {});
Coordination::Error code = zookeeper->tryMulti(ops, op_results);
if (code == Coordination::Error::ZOK)
delimiting_block_lock->assumeUnlocked();
else if (code == Coordination::Error::ZBADVERSION)
{
/// Cannot retry automatically, because some zookeeper ops were lost on the first attempt. Will retry on DDLWorker-level.
if (query_context->getZooKeeperMetadataTransaction())
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot execute alter, because alter partition version was suddenly changed due "
"to concurrent alter");
continue;
}
else
zkutil::KeeperMultiException::check(code, ops, op_results);
{
auto data_parts_lock = lockParts();
transaction.commit(&data_parts_lock);
if (replace)
{
parts_holder = getDataPartsVectorInPartitionForInternalUsage(MergeTreeDataPartState::Active, drop_range.partition_id, &data_parts_lock);
removePartsInRangeFromWorkingSet(NO_TRANSACTION_RAW, drop_range, data_parts_lock);
}
}
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(dst_parts, watch.elapsed(), profile_events_scope.getSnapshot()));
}
catch (...)
{
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(dst_parts, watch.elapsed()), ExecutionStatus::fromCurrentException("", true));
for (const auto & dst_part : dst_parts)
unlockSharedData(*dst_part);
throw;
}
String log_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*op_results.back()).path_created;
entry.znode_name = log_znode_path.substr(log_znode_path.find_last_of('/') + 1);
for (auto & lock : ephemeral_locks)
lock.assumeUnlocked();
lock2.reset();
lock1.reset();
/// We need to pull the DROP_RANGE before cleaning the replaced parts (otherwise CHeckThread may decide that parts are lost)
queue.pullLogsToQueue(getZooKeeperAndAssertNotReadonly(), {}, ReplicatedMergeTreeQueue::SYNC);
parts_holder.clear();
cleanup_thread.wakeup();
waitForLogEntryToBeProcessedIfNecessary(entry, query_context);
return;
}
throw Exception(
ErrorCodes::CANNOT_ASSIGN_ALTER, "Cannot assign ALTER PARTITION, because another ALTER PARTITION query was concurrently executed");
}
void StorageReplicatedMergeTree::movePartitionToTable(const StoragePtr & dest_table, const ASTPtr & partition, ContextPtr query_context)
{
auto lock1 = lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
auto lock2 = dest_table->lockForShare(query_context->getCurrentQueryId(), query_context->getSettingsRef().lock_acquire_timeout);
auto storage_settings_ptr = getSettings();
auto dest_table_storage = std::dynamic_pointer_cast<StorageReplicatedMergeTree>(dest_table);
if (!dest_table_storage)
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Table {} supports movePartitionToTable only for ReplicatedMergeTree family of table engines. "
"Got {}", getStorageID().getNameForLogs(), dest_table->getName());
if (dest_table_storage->getStoragePolicy() != this->getStoragePolicy())
throw Exception(ErrorCodes::UNKNOWN_POLICY,
"Destination table {} should have the same storage policy of source table {}. {}: {}, {}: {}",
dest_table_storage->getStorageID().getNameForLogs(),
getStorageID().getNameForLogs(), getStorageID().getNameForLogs(),
this->getStoragePolicy()->getName(), getStorageID().getNameForLogs(),
dest_table_storage->getStoragePolicy()->getName());
auto dest_metadata_snapshot = dest_table->getInMemoryMetadataPtr();
auto metadata_snapshot = getInMemoryMetadataPtr();
Stopwatch watch;
ProfileEventsScope profile_events_scope;
MergeTreeData & src_data = dest_table_storage->checkStructureAndGetMergeTreeData(*this, metadata_snapshot, dest_metadata_snapshot);
auto src_data_id = src_data.getStorageID();
String partition_id = getPartitionIDFromQuery(partition, query_context);
/// A range for log entry to remove parts from the source table (myself).
auto zookeeper = getZooKeeper();
/// Retry if alter_partition_version changes
for (size_t retry = 0; retry < 1000; ++retry)
{
String alter_partition_version_path = zookeeper_path + "/alter_partition_version";
Coordination::Stat alter_partition_version_stat;
zookeeper->get(alter_partition_version_path, &alter_partition_version_stat);
MergeTreePartInfo drop_range;
std::optional<EphemeralLockInZooKeeper> delimiting_block_lock;
getFakePartCoveringAllPartsInPartition(partition_id, drop_range, delimiting_block_lock, true);
String drop_range_fake_part_name = getPartNamePossiblyFake(format_version, drop_range);
DataPartPtr covering_part;
DataPartsVector src_all_parts;
{
/// NOTE: Some covered parts may be missing in src_all_parts if corresponding log entries are not executed yet.
auto parts_lock = src_data.lockParts();
src_all_parts = src_data.getActivePartsToReplace(drop_range, drop_range_fake_part_name, covering_part, parts_lock);
}
if (covering_part)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Got part {} covering drop range {}, it's a bug",
covering_part->name, drop_range_fake_part_name);
/// After allocating block number for drop_range we must ensure that it does not intersect block numbers
/// allocated by concurrent REPLACE query.
/// We could check it in multi-request atomically with creation of DROP_RANGE entry in source table log,
/// but it's better to check it here and fail as early as possible (before we have done something to destination table).
Coordination::Error version_check_code = zookeeper->trySet(alter_partition_version_path, "", alter_partition_version_stat.version);
if (version_check_code != Coordination::Error::ZOK)
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER, "Cannot DROP PARTITION in {} after copying partition to {}, "
"because another ALTER PARTITION query was concurrently executed",
getStorageID().getFullTableName(), dest_table_storage->getStorageID().getFullTableName());
DataPartsVector src_parts;
MutableDataPartsVector dst_parts;
Strings block_id_paths;
Strings part_checksums;
std::vector<EphemeralLockInZooKeeper> ephemeral_locks;
LOG_DEBUG(log, "Cloning {} parts", src_all_parts.size());
static const String TMP_PREFIX = "tmp_move_from_";
/// Clone parts into destination table.
String dest_alter_partition_version_path = dest_table_storage->zookeeper_path + "/alter_partition_version";
Coordination::Stat dest_alter_partition_version_stat;
zookeeper->get(dest_alter_partition_version_path, &dest_alter_partition_version_stat);
std::vector<scope_guard> temporary_parts_locks;
for (const auto & src_part : src_all_parts)
{
if (!dest_table_storage->canReplacePartition(src_part))
throw Exception(ErrorCodes::LOGICAL_ERROR,
"Cannot move partition '{}' because part '{}"
"' has inconsistent granularity with table", partition_id, src_part->name);
String hash_hex = src_part->checksums.getTotalChecksumHex();
String block_id_path;
auto lock = dest_table_storage->allocateBlockNumber(partition_id, zookeeper, block_id_path);
if (!lock)
{
LOG_INFO(log, "Part {} (hash {}) has been already attached", src_part->name, hash_hex);
continue;
}
UInt64 index = lock->getNumber();
MergeTreePartInfo dst_part_info(partition_id, index, index, src_part->info.level);
/// Don't do hardlinks in case of zero-copy at any side (defensive programming)
bool zero_copy_enabled = storage_settings_ptr->allow_remote_fs_zero_copy_replication
|| dynamic_cast<const MergeTreeData *>(dest_table.get())->getSettings()->allow_remote_fs_zero_copy_replication;
IDataPartStorage::ClonePartParams clone_params
{
.copy_instead_of_hardlink = zero_copy_enabled && src_part->isStoredOnRemoteDiskWithZeroCopySupport(),
.metadata_version_to_write = dest_metadata_snapshot->getMetadataVersion()
};
auto [dst_part, dst_part_lock] = dest_table_storage->cloneAndLoadDataPartOnSameDisk(src_part, TMP_PREFIX, dst_part_info, dest_metadata_snapshot, clone_params);
src_parts.emplace_back(src_part);
dst_parts.emplace_back(dst_part);
temporary_parts_locks.emplace_back(std::move(dst_part_lock));
ephemeral_locks.emplace_back(std::move(*lock));
block_id_paths.emplace_back(block_id_path);
part_checksums.emplace_back(hash_hex);
}
ReplicatedMergeTreeLogEntryData entry_delete;
{
entry_delete.type = LogEntry::DROP_RANGE;
entry_delete.source_replica = replica_name;
entry_delete.new_part_name = drop_range_fake_part_name;
entry_delete.detach = false;
entry_delete.create_time = time(nullptr);
}
ReplicatedMergeTreeLogEntryData entry;
{
MergeTreePartInfo drop_range_dest = makeDummyDropRangeForMovePartitionOrAttachPartitionFrom(partition_id);
entry.type = ReplicatedMergeTreeLogEntryData::REPLACE_RANGE;
entry.source_replica = dest_table_storage->replica_name;
entry.create_time = time(nullptr);
entry.replace_range_entry = std::make_shared<ReplicatedMergeTreeLogEntryData::ReplaceRangeEntry>();
auto & entry_replace = *entry.replace_range_entry;
entry_replace.drop_range_part_name = getPartNamePossiblyFake(format_version, drop_range_dest);
entry_replace.from_database = src_data_id.database_name;
entry_replace.from_table = src_data_id.table_name;
for (const auto & part : src_parts)
entry_replace.src_part_names.emplace_back(part->name);
for (const auto & part : dst_parts)
entry_replace.new_part_names.emplace_back(part->name);
for (const String & checksum : part_checksums)
entry_replace.part_names_checksums.emplace_back(checksum);
entry_replace.columns_version = -1;
}
/// Cancel concurrent inserts in range
clearLockedBlockNumbersInPartition(*zookeeper, drop_range.partition_id, drop_range.max_block, drop_range.max_block);
clearBlocksInPartition(*zookeeper, drop_range.partition_id, drop_range.max_block, drop_range.max_block);
Coordination::Responses op_results;
/// We should hold replaced parts until we actually create DROP_RANGE in ZooKeeper
DataPartsVector parts_holder;
try
{
Coordination::Requests ops;
for (size_t i = 0; i < dst_parts.size(); ++i)
{
dest_table_storage->getCommitPartOps(ops, dst_parts[i], block_id_paths[i]);
ephemeral_locks[i].getUnlockOp(ops);
}
/// Check and update version to avoid race with DROP_RANGE
ops.emplace_back(zkutil::makeSetRequest(dest_alter_partition_version_path, "", dest_alter_partition_version_stat.version));
/// Just update version, because merges assignment relies on it
ops.emplace_back(zkutil::makeSetRequest(fs::path(dest_table_storage->zookeeper_path) / "log", "", -1));
ops.emplace_back(zkutil::makeCreateRequest(fs::path(dest_table_storage->zookeeper_path) / "log/log-",
entry.toString(), zkutil::CreateMode::PersistentSequential));
{
Transaction transaction(*dest_table_storage, NO_TRANSACTION_RAW);
auto src_data_parts_lock = lockParts();
auto dest_data_parts_lock = dest_table_storage->lockParts();
for (auto & part : dst_parts)
dest_table_storage->renameTempPartAndReplaceUnlocked(part, transaction, dest_data_parts_lock);
for (const auto & dst_part : dst_parts)
dest_table_storage->lockSharedData(*dst_part, false, /*hardlinked_files*/ {});
Coordination::Error code = zookeeper->tryMulti(ops, op_results);
if (code == Coordination::Error::ZBADVERSION)
continue;
else
zkutil::KeeperMultiException::check(code, ops, op_results);
parts_holder = getDataPartsVectorInPartitionForInternalUsage(MergeTreeDataPartState::Active, drop_range.partition_id, &src_data_parts_lock);
removePartsInRangeFromWorkingSet(NO_TRANSACTION_RAW, drop_range, src_data_parts_lock);
transaction.commit(&src_data_parts_lock);
}
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(dst_parts, watch.elapsed(), profile_events_scope.getSnapshot()));
}
catch (...)
{
PartLog::addNewParts(getContext(), PartLog::createPartLogEntries(dst_parts, watch.elapsed()), ExecutionStatus::fromCurrentException("", true));
for (const auto & dst_part : dst_parts)
dest_table_storage->unlockSharedData(*dst_part);
throw;
}
String log_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*op_results.back()).path_created;
entry.znode_name = log_znode_path.substr(log_znode_path.find_last_of('/') + 1);
for (auto & lock : ephemeral_locks)
lock.assumeUnlocked();
lock2.reset();
dest_table_storage->waitForLogEntryToBeProcessedIfNecessary(entry, query_context);
/// Create DROP_RANGE for the source table
Coordination::Requests ops_src;
ops_src.emplace_back(zkutil::makeCreateRequest(
fs::path(zookeeper_path) / "log/log-", entry_delete.toString(), zkutil::CreateMode::PersistentSequential));
/// Just update version, because merges assignment relies on it
ops_src.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "log", "", -1));
delimiting_block_lock->getUnlockOp(ops_src);
op_results = zookeeper->multi(ops_src);
log_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*op_results.front()).path_created;
entry_delete.znode_name = log_znode_path.substr(log_znode_path.find_last_of('/') + 1);
lock1.reset();
/// We need to pull the DROP_RANGE before cleaning the replaced parts (otherwise CHeckThread may decide that parts are lost)
queue.pullLogsToQueue(getZooKeeperAndAssertNotReadonly(), {}, ReplicatedMergeTreeQueue::SYNC);
parts_holder.clear();
cleanup_thread.wakeup();
waitForLogEntryToBeProcessedIfNecessary(entry_delete, query_context);
/// Cleaning possibly stored information about parts from /quorum/last_part node in ZooKeeper.
cleanLastPartNode(partition_id);
return;
}
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot assign ALTER PARTITION, because another ALTER PARTITION query was concurrently executed");
}
void StorageReplicatedMergeTree::movePartitionToShard(
const ASTPtr & partition, bool move_part, const String & to, ContextPtr /*query_context*/)
{
/// This is a lightweight operation that only optimistically checks if it could succeed and queues tasks.
if (!move_part)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "MOVE PARTITION TO SHARD is not supported, use MOVE PART instead");
if (zkutil::normalizeZooKeeperPath(zookeeper_path, /* check_starts_with_slash */ true) == zkutil::normalizeZooKeeperPath(to, /* check_starts_with_slash */ true))
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Source and destination are the same");
auto zookeeper = getZooKeeperAndAssertNotReadonly();
String part_name = partition->as<ASTLiteral &>().value.safeGet<String>();
auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
auto part = getPartIfExists(part_info, {MergeTreeDataPartState::Active});
if (!part)
throw Exception(ErrorCodes::NO_SUCH_DATA_PART, "Part {} not found locally", part_name);
if (part->uuid == UUIDHelpers::Nil)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Part {} does not have an uuid assigned and it can't be moved between shards", part_name);
ReplicatedMergeTreeMergePredicate merge_pred = queue.getMergePredicate(zookeeper, PartitionIdsHint{part_info.partition_id});
/// The following block is pretty much copy & paste from StorageReplicatedMergeTree::dropPart to avoid conflicts while this is WIP.
/// Extract it to a common method and re-use it before merging.
{
if (partIsLastQuorumPart(part->info))
{
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Part {} is last inserted part with quorum in partition. Would not be able to drop",
part_name);
}
/// canMergeSinglePart is overlapping with dropPart, let's try to use the same code.
String out_reason;
if (!merge_pred.canMergeSinglePart(part, out_reason))
throw Exception(ErrorCodes::PART_IS_TEMPORARILY_LOCKED, "Part is busy, reason: {}", out_reason);
}
{
/// Optimistic check that for compatible destination table structure.
checkTableStructure(to, getInMemoryMetadataPtr());
}
PinnedPartUUIDs src_pins;
PinnedPartUUIDs dst_pins;
{
String s = zookeeper->get(zookeeper_path + "/pinned_part_uuids", &src_pins.stat);
src_pins.fromString(s);
}
{
String s = zookeeper->get(to + "/pinned_part_uuids", &dst_pins.stat);
dst_pins.fromString(s);
}
if (src_pins.part_uuids.contains(part->uuid) || dst_pins.part_uuids.contains(part->uuid))
throw Exception(ErrorCodes::PART_IS_TEMPORARILY_LOCKED, "Part {} has it's uuid ({}) already pinned.", part_name, part->uuid);
src_pins.part_uuids.insert(part->uuid);
dst_pins.part_uuids.insert(part->uuid);
PartMovesBetweenShardsOrchestrator::Entry part_move_entry;
part_move_entry.state = PartMovesBetweenShardsOrchestrator::EntryState::SYNC_SOURCE;
part_move_entry.create_time = std::time(nullptr);
part_move_entry.update_time = part_move_entry.create_time;
part_move_entry.task_uuid = UUIDHelpers::generateV4();
part_move_entry.part_name = part->name;
part_move_entry.part_uuid = part->uuid;
part_move_entry.to_shard = to;
Coordination::Requests ops;
ops.emplace_back(zkutil::makeCheckRequest(zookeeper_path + "/log", merge_pred.getVersion())); /// Make sure no new events were added to the log.
ops.emplace_back(zkutil::makeSetRequest(zookeeper_path + "/pinned_part_uuids", src_pins.toString(), src_pins.stat.version));
ops.emplace_back(zkutil::makeSetRequest(to + "/pinned_part_uuids", dst_pins.toString(), dst_pins.stat.version));
ops.emplace_back(zkutil::makeCreateRequest(
part_moves_between_shards_orchestrator.entries_znode_path + "/task-",
part_move_entry.toString(),
zkutil::CreateMode::PersistentSequential));
Coordination::Responses responses;
Coordination::Error rc = zookeeper->tryMulti(ops, responses);
zkutil::KeeperMultiException::check(rc, ops, responses);
String task_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*responses.back()).path_created;
LOG_DEBUG(log, "Created task for part movement between shards at {}", task_znode_path);
/// TODO(nv): Nice to have support for `alter_sync`.
/// For now use the system.part_moves_between_shards table for status.
}
CancellationCode StorageReplicatedMergeTree::killPartMoveToShard(const UUID & task_uuid)
{
return part_moves_between_shards_orchestrator.killPartMoveToShard(task_uuid);
}
void StorageReplicatedMergeTree::getCommitPartOps(
Coordination::Requests & ops,
const DataPartPtr & part,
const String & block_id_path) const
{
if (block_id_path.empty())
return getCommitPartOps(ops, part, std::vector<String>());
else
return getCommitPartOps(ops, part, std::vector<String>({block_id_path}));
}
void StorageReplicatedMergeTree::getCommitPartOps(
Coordination::Requests & ops,
const DataPartPtr & part,
const std::vector<String> & block_id_paths) const
{
const String & part_name = part->name;
const auto storage_settings_ptr = getSettings();
for (const String & block_id_path : block_id_paths)
{
/// Make final duplicate check and commit block_id
ops.emplace_back(
zkutil::makeCreateRequest(
block_id_path,
part_name, /// We will be able to know original part number for duplicate blocks, if we want.
zkutil::CreateMode::Persistent));
}
/// Information about the part, in the replica
if (storage_settings_ptr->use_minimalistic_part_header_in_zookeeper)
{
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(replica_path) / "parts" / part->name,
ReplicatedMergeTreePartHeader::fromColumnsAndChecksums(part->getColumns(), part->checksums).toString(),
zkutil::CreateMode::Persistent));
}
else
{
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(replica_path) / "parts" / part->name,
"",
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(replica_path) / "parts" / part->name / "columns",
part->getColumns().toString(),
zkutil::CreateMode::Persistent));
ops.emplace_back(zkutil::makeCreateRequest(
fs::path(replica_path) / "parts" / part->name / "checksums",
getChecksumsForZooKeeper(part->checksums),
zkutil::CreateMode::Persistent));
}
}
ReplicatedMergeTreeAddress StorageReplicatedMergeTree::getReplicatedMergeTreeAddress() const
{
auto host_port = getContext()->getInterserverIOAddress();
auto table_id = getStorageID();
ReplicatedMergeTreeAddress res;
res.host = host_port.first;
res.replication_port = host_port.second;
res.queries_port = getContext()->getTCPPort();
res.database = table_id.database_name;
res.table = table_id.table_name;
res.scheme = getContext()->getInterserverScheme();
return res;
}
ActionLock StorageReplicatedMergeTree::getActionLock(StorageActionBlockType action_type)
{
if (action_type == ActionLocks::PartsMerge)
return merger_mutator.merges_blocker.cancel();
if (action_type == ActionLocks::PartsTTLMerge)
return merger_mutator.ttl_merges_blocker.cancel();
if (action_type == ActionLocks::PartsFetch)
return fetcher.blocker.cancel();
if (action_type == ActionLocks::PartsSend)
{
auto data_parts_exchange_ptr = std::atomic_load(&data_parts_exchange_endpoint);
return data_parts_exchange_ptr ? data_parts_exchange_ptr->blocker.cancel() : ActionLock();
}
if (action_type == ActionLocks::ReplicationQueue)
return queue.actions_blocker.cancel();
if (action_type == ActionLocks::PartsMove)
return parts_mover.moves_blocker.cancel();
if (action_type == ActionLocks::PullReplicationLog)
return queue.pull_log_blocker.cancel();
return {};
}
void StorageReplicatedMergeTree::onActionLockRemove(StorageActionBlockType action_type)
{
if (action_type == ActionLocks::PartsMerge || action_type == ActionLocks::PartsTTLMerge
|| action_type == ActionLocks::PartsFetch || action_type == ActionLocks::PartsSend
|| action_type == ActionLocks::ReplicationQueue)
background_operations_assignee.trigger();
else if (action_type == ActionLocks::PartsMove)
background_moves_assignee.trigger();
}
bool StorageReplicatedMergeTree::waitForProcessingQueue(UInt64 max_wait_milliseconds, SyncReplicaMode sync_mode)
{
/// Let's fetch new log entries firstly
queue.pullLogsToQueue(getZooKeeperAndAssertNotReadonly(), {}, ReplicatedMergeTreeQueue::SYNC);
if (sync_mode == SyncReplicaMode::PULL)
return true;
/// This is significant, because the execution of this task could be delayed at BackgroundPool.
/// And we force it to be executed.
background_operations_assignee.trigger();
std::unordered_set<String> wait_for_ids;
std::atomic_bool was_interrupted = false;
Poco::Event target_entry_event;
auto callback = [this, &target_entry_event, &wait_for_ids, &was_interrupted, sync_mode]
(size_t new_queue_size, const String * removed_log_entry_id)
{
if (partial_shutdown_called)
{
was_interrupted = true;
target_entry_event.set();
return;
}
if (sync_mode == SyncReplicaMode::STRICT)
{
/// Wait for queue to become empty
if (new_queue_size == 0)
target_entry_event.set();
return;
}
if (removed_log_entry_id)
wait_for_ids.erase(*removed_log_entry_id);
if (wait_for_ids.empty())
target_entry_event.set();
};
const auto handler = queue.addSubscriber(std::move(callback), wait_for_ids, sync_mode);
if (!target_entry_event.tryWait(max_wait_milliseconds))
return false;
if (was_interrupted)
throw Exception(ErrorCodes::ABORTED, "Shutdown is called for table");
return true;
}
bool StorageReplicatedMergeTree::dropPartImpl(
zkutil::ZooKeeperPtr & zookeeper, String part_name, LogEntry & entry, bool detach, bool throw_if_noop)
{
LOG_TRACE(log, "Will try to insert a log entry to DROP_PART for part {}", part_name);
auto part_info = MergeTreePartInfo::fromPartName(part_name, format_version);
while (true)
{
ReplicatedMergeTreeMergePredicate merge_pred = queue.getMergePredicate(zookeeper, PartitionIdsHint{part_info.partition_id});
auto part = getPartIfExists(part_info, {MergeTreeDataPartState::Active});
if (!part)
{
if (throw_if_noop)
throw Exception(ErrorCodes::NO_SUCH_DATA_PART, "Part {} not found locally, won't try to drop it.", part_name);
return false;
}
if (merge_pred.isGoingToBeDropped(part->info))
{
if (throw_if_noop)
throw Exception(ErrorCodes::PART_IS_TEMPORARILY_LOCKED, "Already has DROP RANGE for part {} in queue.", part_name);
return false;
}
/// There isn't a lot we can do otherwise. Can't cancel merges because it is possible that a replica already
/// finished the merge.
String out_reason;
if (!merge_pred.canMergeSinglePart(part, out_reason))
{
if (throw_if_noop)
throw Exception::createDeprecated(out_reason, ErrorCodes::PART_IS_TEMPORARILY_LOCKED);
return false;
}
if (merge_pred.partParticipatesInReplaceRange(part, out_reason))
{
if (throw_if_noop)
throw Exception::createDeprecated(out_reason, ErrorCodes::PART_IS_TEMPORARILY_LOCKED);
return false;
}
if (partIsLastQuorumPart(part->info))
{
if (throw_if_noop)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Part {} is last inserted part with quorum in partition. Cannot drop", part_name);
return false;
}
if (partIsInsertingWithParallelQuorum(part->info))
{
if (throw_if_noop)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Part {} is inserting with parallel quorum. Cannot drop", part_name);
return false;
}
Coordination::Requests ops;
/// NOTE Don't need to remove block numbers too, because no in-progress inserts in the range are possible
getClearBlocksInPartitionOps(ops, *zookeeper, part_info.partition_id, part_info.min_block, part_info.max_block);
size_t clear_block_ops_size = ops.size();
/// If `part_name` is result of a recent merge and source parts are still available then
/// DROP_PART with detach will move this part together with source parts to `detached/` dir.
entry.type = LogEntry::DROP_PART;
entry.source_replica = replica_name;
/// We don't set fake drop level (999999999) for the single part drop range.
/// First of all we don't guarantee anything other than the part will not be
/// active after DROP_PART, but covering part (without data of dropped part) can exist.
/// If we add part with 9999999 level than we can break invariant in virtual_parts of
/// the queue.
entry.new_part_name = getPartNamePossiblyFake(format_version, part->info);
entry.detach = detach;
entry.create_time = time(nullptr);
ops.emplace_back(zkutil::makeCheckRequest(fs::path(zookeeper_path) / "log", merge_pred.getVersion())); /// Make sure no new events were added to the log.
ops.emplace_back(zkutil::makeCreateRequest(fs::path(zookeeper_path) / "log/log-", entry.toString(), zkutil::CreateMode::PersistentSequential));
/// Just update version, because merges assignment relies on it
ops.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "log", "", -1));
Coordination::Responses responses;
Coordination::Error rc = zookeeper->tryMulti(ops, responses);
if (rc == Coordination::Error::ZBADVERSION)
{
LOG_TRACE(log, "A new log entry appeared while trying to commit DROP RANGE. Retry.");
continue;
}
else if (rc == Coordination::Error::ZNONODE)
{
LOG_TRACE(log, "Other replica already removing same part {} or part deduplication node was removed by background thread. Retry.", part_name);
continue;
}
else
zkutil::KeeperMultiException::check(rc, ops, responses);
String log_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*responses[clear_block_ops_size + 1]).path_created;
entry.znode_name = log_znode_path.substr(log_znode_path.find_last_of('/') + 1);
LOG_TRACE(log, "DROP RANGE for part {} inserted with znode name {}", part_name, entry.znode_name);
return true;
}
}
bool StorageReplicatedMergeTree::addOpsToDropAllPartsInPartition(
zkutil::ZooKeeper & zookeeper, const String & partition_id, bool detach,
Coordination::Requests & ops, std::vector<LogEntryPtr> & entries,
std::vector<EphemeralLockInZooKeeper> & delimiting_block_locks,
std::vector<size_t> & log_entry_ops_idx)
{
MergeTreePartInfo drop_range_info;
/// It would prevent other replicas from assigning merges which intersect locked block number.
std::optional<EphemeralLockInZooKeeper> delimiting_block_lock;
if (!getFakePartCoveringAllPartsInPartition(partition_id, drop_range_info, delimiting_block_lock))
{
LOG_INFO(log, "Will not drop partition {}, it is empty.", partition_id);
return false;
}
/// Cancel concurrent inserts in range
clearLockedBlockNumbersInPartition(zookeeper, partition_id, drop_range_info.min_block, drop_range_info.max_block);
clearBlocksInPartition(zookeeper, partition_id, drop_range_info.min_block, drop_range_info.max_block);
String drop_range_fake_part_name = getPartNamePossiblyFake(format_version, drop_range_info);
LOG_DEBUG(log, "Disabled merges covered by range {}", drop_range_fake_part_name);
/// Finally, having achieved the necessary invariants, you can put an entry in the log.
auto entry = std::make_shared<LogEntry>();
entry->type = LogEntry::DROP_RANGE;
entry->source_replica = replica_name;
entry->new_part_name = drop_range_fake_part_name;
entry->detach = detach;
entry->create_time = time(nullptr);
log_entry_ops_idx.push_back(ops.size());
ops.emplace_back(zkutil::makeCreateRequest(fs::path(zookeeper_path) / "log/log-", entry->toString(),
zkutil::CreateMode::PersistentSequential));
delimiting_block_lock->getUnlockOp(ops);
delimiting_block_locks.push_back(std::move(*delimiting_block_lock));
entries.push_back(std::move(entry));
return true;
}
void StorageReplicatedMergeTree::dropAllPartsInPartitions(
zkutil::ZooKeeper & zookeeper, const Strings & partition_ids, std::vector<LogEntryPtr> & entries, ContextPtr query_context, bool detach)
{
entries.reserve(partition_ids.size());
/// Retry if alter_partition_version changes
for (size_t retry = 0; retry < 1000; ++retry)
{
entries.clear();
String alter_partition_version_path = zookeeper_path + "/alter_partition_version";
Coordination::Stat alter_partition_version_stat;
zookeeper.get(alter_partition_version_path, &alter_partition_version_stat);
Coordination::Requests ops;
std::vector<EphemeralLockInZooKeeper> delimiting_block_locks;
std::vector<size_t> log_entry_ops_idx;
ops.reserve(partition_ids.size() * 2);
delimiting_block_locks.reserve(partition_ids.size());
log_entry_ops_idx.reserve(partition_ids.size());
for (const auto & partition_id : partition_ids)
addOpsToDropAllPartsInPartition(zookeeper, partition_id, detach, ops, entries, delimiting_block_locks, log_entry_ops_idx);
/// Check and update version to avoid race with REPLACE_RANGE.
/// Otherwise new parts covered by drop_range_info may appear after execution of current DROP_RANGE entry
/// as a result of execution of concurrently created REPLACE_RANGE entry.
ops.emplace_back(zkutil::makeSetRequest(alter_partition_version_path, "", alter_partition_version_stat.version));
/// Just update version, because merges assignment relies on it
ops.emplace_back(zkutil::makeSetRequest(fs::path(zookeeper_path) / "log", "", -1));
if (auto txn = query_context->getZooKeeperMetadataTransaction())
txn->moveOpsTo(ops);
Coordination::Responses responses;
Coordination::Error code = zookeeper.tryMulti(ops, responses);
if (code == Coordination::Error::ZOK)
{
for (auto & lock : delimiting_block_locks)
lock.assumeUnlocked();
}
else if (code == Coordination::Error::ZBADVERSION)
{
/// Cannot retry automatically, because some zookeeper ops were lost on the first attempt. Will retry on DDLWorker-level.
if (query_context->getZooKeeperMetadataTransaction())
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot execute alter, because alter partition version was suddenly changed due "
"to concurrent alter");
continue;
}
else
zkutil::KeeperMultiException::check(code, ops, responses);
assert(entries.size() == log_entry_ops_idx.size());
for (size_t i = 0; i < entries.size(); ++i)
{
String log_znode_path = dynamic_cast<const Coordination::CreateResponse &>(*responses[log_entry_ops_idx[i]]).path_created;
entries[i]->znode_name = log_znode_path.substr(log_znode_path.find_last_of('/') + 1);
auto drop_range_info = MergeTreePartInfo::fromPartName(entries[i]->new_part_name, format_version);
getContext()->getMergeList().cancelInPartition(getStorageID(), drop_range_info.partition_id, drop_range_info.max_block);
}
return;
}
throw Exception(ErrorCodes::CANNOT_ASSIGN_ALTER,
"Cannot assign ALTER PARTITION because another ALTER PARTITION query was concurrently executed");
}
StorageReplicatedMergeTree::LogEntryPtr StorageReplicatedMergeTree::dropAllPartsInPartition(
zkutil::ZooKeeper & zookeeper, const String & partition_id, ContextPtr query_context, bool detach)
{
Strings partition_ids = {partition_id};
std::vector<LogEntryPtr> entries;
dropAllPartsInPartitions(zookeeper, partition_ids, entries, query_context, detach);
if (entries.empty())
return {};
return entries[0];
}
void StorageReplicatedMergeTree::enqueuePartForCheck(const String & part_name, time_t delay_to_check_seconds)
{
MergeTreePartInfo covering_drop_range;
/// NOTE This check is just an optimization, it's not reliable because drop entry could be removed concurrently.
/// See also ReplicatedMergeTreePartCheckThread::cancelRemovedPartsCheck
if (queue.isGoingToBeDropped(MergeTreePartInfo::fromPartName(part_name, format_version), &covering_drop_range))
{
LOG_WARNING(log, "Do not enqueue part {} for check because it's covered by drop range {} and going to be removed",
part_name, covering_drop_range.getPartNameForLogs());
return;
}
part_check_thread.enqueuePart(part_name, delay_to_check_seconds);
}
CheckResults StorageReplicatedMergeTree::checkData(const ASTPtr & query, ContextPtr local_context)
{
CheckResults results;
DataPartsVector data_parts;
if (const auto & check_query = query->as<ASTCheckQuery &>(); check_query.partition)
{
String partition_id = getPartitionIDFromQuery(check_query.partition, local_context);
data_parts = getVisibleDataPartsVectorInPartition(local_context, partition_id);
}
else
data_parts = getVisibleDataPartsVector(local_context);
{
auto part_check_lock = part_check_thread.pausePartsCheck();
for (auto & part : data_parts)
{
try
{
results.push_back(part_check_thread.checkPartAndFix(part->name));
}
catch (const Exception & ex)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
results.emplace_back(part->name, false, "Check of part finished with error: '" + ex.message() + "'");
}
}
}
return results;
}
bool StorageReplicatedMergeTree::canUseZeroCopyReplication() const
{
auto settings_ptr = getSettings();
if (!settings_ptr->allow_remote_fs_zero_copy_replication)
return false;
auto disks = getStoragePolicy()->getDisks();
for (const auto & disk : disks)
{
if (disk->supportZeroCopyReplication())
return true;
}
return false;
}
void StorageReplicatedMergeTree::checkBrokenDisks()
{
auto disks = getStoragePolicy()->getDisks();
std::unique_ptr<DataPartsVector> parts;
for (auto disk_it = disks.rbegin(); disk_it != disks.rend(); ++disk_it)
{
auto disk_ptr = *disk_it;
if (disk_ptr->isBroken())
{
{
std::lock_guard lock(last_broken_disks_mutex);
if (!last_broken_disks.insert(disk_ptr->getName()).second)
continue;
}
LOG_INFO(log, "Scanning parts to recover on broken disk {} with path {}", disk_ptr->getName(), disk_ptr->getPath());
if (!parts)
parts = std::make_unique<DataPartsVector>(getDataPartsVectorForInternalUsage());
for (auto & part : *parts)
{
if (part->getDataPartStorage().getDiskName() == disk_ptr->getName())
broken_part_callback(part->name);
}
continue;
}
else
{
{
std::lock_guard lock(last_broken_disks_mutex);
if (last_broken_disks.erase(disk_ptr->getName()) > 0)
LOG_INFO(
log,
"Disk {} with path {} is recovered. Exclude it from last_broken_disks",
disk_ptr->getName(),
disk_ptr->getPath());
}
}
}
}
bool StorageReplicatedMergeTree::canUseAdaptiveGranularity() const
{
const auto storage_settings_ptr = getSettings();
return storage_settings_ptr->index_granularity_bytes != 0 &&
(storage_settings_ptr->enable_mixed_granularity_parts ||
(!has_non_adaptive_index_granularity_parts && !other_replicas_fixed_granularity));
}
std::map<int64_t, MutationCommands> StorageReplicatedMergeTree::getAlterMutationCommandsForPart(const DataPartPtr & part) const
{
return queue.getAlterMutationCommandsForPart(part);
}
void StorageReplicatedMergeTree::startBackgroundMovesIfNeeded()
{
if (areBackgroundMovesNeeded())
background_moves_assignee.start();
}
std::unique_ptr<MergeTreeSettings> StorageReplicatedMergeTree::getDefaultSettings() const
{
return std::make_unique<MergeTreeSettings>(getContext()->getReplicatedMergeTreeSettings());
}
String StorageReplicatedMergeTree::getTableSharedID() const
{
std::lock_guard lock(table_shared_id_mutex);
/// If we has metadata or, we don't know about metadata -- try to create shared ID
/// Otherwise table is already dropped, doesn't make sense to do anything with shared ID
if (has_metadata_in_zookeeper.value_or(true))
{
/// Can happen if table was partially initialized before drop by DatabaseCatalog
if (table_shared_id == UUIDHelpers::Nil)
createTableSharedID();
}
else
{
return toString(UUIDHelpers::Nil);
}
return toString(table_shared_id);
}
size_t StorageReplicatedMergeTree::getNumberOfUnfinishedMutations() const
{
return queue.countUnfinishedMutations();
}
void StorageReplicatedMergeTree::createTableSharedID() const
{
LOG_DEBUG(log, "Creating shared ID for table {}", getStorageID().getNameForLogs());
// can be set by the call to getTableSharedID
if (table_shared_id != UUIDHelpers::Nil)
{
LOG_INFO(log, "Shared ID already set to {}", table_shared_id);
return;
}
/// We may call getTableSharedID when table is shut down. If exception happen, restarting thread will be already turned
/// off and nobody will reconnect our zookeeper connection. In this case we use zookeeper connection from
/// context.
ZooKeeperPtr zookeeper;
if (shutdown_called.load())
zookeeper = getZooKeeperIfTableShutDown();
else
zookeeper = getZooKeeper();
String zookeeper_table_id_path = fs::path(zookeeper_path) / "table_shared_id";
String id;
if (!zookeeper->tryGet(zookeeper_table_id_path, id))
{
LOG_DEBUG(log, "Shared ID for table {} doesn't exist in ZooKeeper on path {}", getStorageID().getNameForLogs(), zookeeper_table_id_path);
UUID table_id_candidate;
auto local_storage_id = getStorageID();
if (local_storage_id.uuid != UUIDHelpers::Nil)
table_id_candidate = local_storage_id.uuid;
else
table_id_candidate = UUIDHelpers::generateV4();
id = toString(table_id_candidate);
LOG_DEBUG(log, "Got candidate ID {}, will try to create it in ZooKeeper on path {}", id, zookeeper_table_id_path);
auto code = zookeeper->tryCreate(zookeeper_table_id_path, id, zkutil::CreateMode::Persistent);
if (code == Coordination::Error::ZNODEEXISTS)
{ /// Other replica create node early
id = zookeeper->get(zookeeper_table_id_path);
LOG_DEBUG(log, "Shared ID on path {} concurrently created, will set ID {}", zookeeper_table_id_path, id);
}
else if (code == Coordination::Error::ZNONODE) /// table completely dropped, we can choose any id we want
{
id = toString(UUIDHelpers::Nil);
LOG_DEBUG(log, "Table was completely drop, we can use anything as ID (will use {})", id);
}
else if (code != Coordination::Error::ZOK)
{
throw zkutil::KeeperException::fromPath(code, zookeeper_table_id_path);
}
}
LOG_DEBUG(log, "Initializing table shared ID with {}", id);
table_shared_id = parseFromString<UUID>(id);
}
std::optional<String> StorageReplicatedMergeTree::tryGetTableSharedIDFromCreateQuery(const IAST & create_query, const ContextPtr & global_context)
{
auto zk_path = tryExtractZkPathFromCreateQuery(create_query, global_context);
if (!zk_path)
return {};
String zk_name = zkutil::extractZooKeeperName(*zk_path);
zk_path = zkutil::extractZooKeeperPath(*zk_path, false, nullptr);
zkutil::ZooKeeperPtr zookeeper = (zk_name == getDefaultZooKeeperName()) ? global_context->getZooKeeper() : global_context->getAuxiliaryZooKeeper(zk_name);
String id;
if (!zookeeper->tryGet(fs::path(*zk_path) / "table_shared_id", id))
return {};
return id;
}
zkutil::EphemeralNodeHolderPtr StorageReplicatedMergeTree::lockSharedDataTemporary(const String & part_name, const String & part_id, const DiskPtr & disk) const
{
auto settings = getSettings();
if (!disk || !disk->supportZeroCopyReplication() || !settings->allow_remote_fs_zero_copy_replication)
return {};
zkutil::ZooKeeperPtr zookeeper = tryGetZooKeeper();
if (!zookeeper)
return {};
String id = part_id;
boost::replace_all(id, "/", "_");
String zc_zookeeper_path = getZeroCopyPartPath(*getSettings(), toString(disk->getDataSourceDescription().type), getTableSharedID(),
part_name, zookeeper_path)[0];
String zookeeper_node = fs::path(zc_zookeeper_path) / id / replica_name;
LOG_TRACE(log, "Set zookeeper temporary ephemeral lock {}", zookeeper_node);
createZeroCopyLockNode(
std::make_shared<ZooKeeperWithFaultInjection>(zookeeper), zookeeper_node, zkutil::CreateMode::Ephemeral, false);
LOG_TRACE(log, "Zookeeper temporary ephemeral lock {} created", zookeeper_node);
return zkutil::EphemeralNodeHolder::existing(zookeeper_node, *zookeeper);
}
void StorageReplicatedMergeTree::lockSharedData(
const IMergeTreeDataPart & part,
bool replace_existing_lock,
std::optional<HardlinkedFiles> hardlinked_files) const
{
LOG_DEBUG(log, "Trying to create zero-copy lock for part {}", part.name);
auto zookeeper = tryGetZooKeeper();
if (zookeeper)
return lockSharedData(part, std::make_shared<ZooKeeperWithFaultInjection>(zookeeper), replace_existing_lock, hardlinked_files);
else
return lockSharedData(part, std::make_shared<ZooKeeperWithFaultInjection>(nullptr), replace_existing_lock, hardlinked_files);
}
void StorageReplicatedMergeTree::getLockSharedDataOps(
const IMergeTreeDataPart & part,
const ZooKeeperWithFaultInjectionPtr & zookeeper,
bool replace_existing_lock,
std::optional<HardlinkedFiles> hardlinked_files,
Coordination::Requests & requests) const
{
auto settings = getSettings();
if (!part.isStoredOnDisk() || !settings->allow_remote_fs_zero_copy_replication)
return;
if (!part.getDataPartStorage().supportZeroCopyReplication())
return;
if (zookeeper->isNull())
return;
String id = part.getUniqueId();
boost::replace_all(id, "/", "_");
Strings zc_zookeeper_paths = getZeroCopyPartPath(
*getSettings(), part.getDataPartStorage().getDiskType(), getTableSharedID(),
part.name, zookeeper_path);
String path_to_set_hardlinked_files;
NameSet hardlinks;
if (hardlinked_files.has_value() && !hardlinked_files->hardlinks_from_source_part.empty())
{
path_to_set_hardlinked_files = getZeroCopyPartPath(
*getSettings(), part.getDataPartStorage().getDiskType(), hardlinked_files->source_table_shared_id,
hardlinked_files->source_part_name, zookeeper_path)[0];
hardlinks = hardlinked_files->hardlinks_from_source_part;
}
for (const auto & zc_zookeeper_path : zc_zookeeper_paths)
{
String zookeeper_node = fs::path(zc_zookeeper_path) / id / replica_name;
getZeroCopyLockNodeCreateOps(
zookeeper, zookeeper_node, requests, zkutil::CreateMode::Persistent,
replace_existing_lock, path_to_set_hardlinked_files, hardlinks);
}
}
void StorageReplicatedMergeTree::lockSharedData(
const IMergeTreeDataPart & part,
const ZooKeeperWithFaultInjectionPtr & zookeeper,
bool replace_existing_lock,
std::optional<HardlinkedFiles> hardlinked_files) const
{
auto settings = getSettings();
if (!part.isStoredOnDisk() || !settings->allow_remote_fs_zero_copy_replication)
return;
if (!part.getDataPartStorage().supportZeroCopyReplication())
return;
if (zookeeper->isNull())
return;
String id = part.getUniqueId();
boost::replace_all(id, "/", "_");
Strings zc_zookeeper_paths = getZeroCopyPartPath(
*getSettings(), part.getDataPartStorage().getDiskType(), getTableSharedID(),
part.name, zookeeper_path);
String path_to_set_hardlinked_files;
NameSet hardlinks;
if (hardlinked_files.has_value() && !hardlinked_files->hardlinks_from_source_part.empty())
{
path_to_set_hardlinked_files = getZeroCopyPartPath(
*getSettings(), part.getDataPartStorage().getDiskType(), hardlinked_files->source_table_shared_id,
hardlinked_files->source_part_name, zookeeper_path)[0];
hardlinks = hardlinked_files->hardlinks_from_source_part;
}
for (const auto & zc_zookeeper_path : zc_zookeeper_paths)
{
String zookeeper_node = fs::path(zc_zookeeper_path) / id / replica_name;
LOG_TRACE(log, "Trying to create zookeeper persistent lock {} with hardlinks [{}]", zookeeper_node, fmt::join(hardlinks, ", "));
createZeroCopyLockNode(
zookeeper, zookeeper_node, zkutil::CreateMode::Persistent,
replace_existing_lock, path_to_set_hardlinked_files, hardlinks);
LOG_TRACE(log, "Zookeeper persistent lock {} created", zookeeper_node);
}
}
std::pair<bool, NameSet>
StorageReplicatedMergeTree::unlockSharedData(const IMergeTreeDataPart & part) const
{
return unlockSharedData(part, std::make_shared<ZooKeeperWithFaultInjection>(nullptr));
}
std::pair<bool, NameSet>
StorageReplicatedMergeTree::unlockSharedData(const IMergeTreeDataPart & part, const ZooKeeperWithFaultInjectionPtr & zookeeper) const
{
auto settings = getSettings();
if (!settings->allow_remote_fs_zero_copy_replication)
return std::make_pair(true, NameSet{});
if (!part.isStoredOnDisk())
{
LOG_TRACE(log, "Part {} is not stored on disk, blobs can be removed", part.name);
return std::make_pair(true, NameSet{});
}
if (!part.getDataPartStorage().supportZeroCopyReplication())
{
LOG_TRACE(log, "Part {} is not stored on zero-copy replicated disk, blobs can be removed", part.name);
return std::make_pair(true, NameSet{});
}
auto shared_id = getTableSharedID();
if (shared_id == toString(UUIDHelpers::Nil))
{
if (zookeeper->exists(zookeeper_path))
{
LOG_WARNING(log, "Not removing shared data for part {} because replica does not have metadata in ZooKeeper, "
"but table path exist and other replicas may exist. It may leave some garbage on S3", part.name);
return std::make_pair(false, NameSet{});
}
LOG_TRACE(log, "Part {} blobs can be removed, because table {} completely dropped", part.name, getStorageID().getNameForLogs());
return std::make_pair(true, NameSet{});
}
/// If part is temporary refcount file may be absent
if (part.getDataPartStorage().exists(IMergeTreeDataPart::FILE_FOR_REFERENCES_CHECK))
{
auto ref_count = part.getDataPartStorage().getRefCount(IMergeTreeDataPart::FILE_FOR_REFERENCES_CHECK);
if (ref_count > 0) /// Keep part shard info for frozen backups
{
LOG_TRACE(log, "Part {} has more than zero local references ({}), blobs cannot be removed", part.name, ref_count);
return std::make_pair(false, NameSet{});
}
else
{
LOG_TRACE(log, "Part {} local references is zero, will check blobs can be removed in zookeeper", part.name);
}
}
else
{
LOG_TRACE(log, "Part {} looks temporary, because {} file doesn't exists, blobs can be removed", part.name, IMergeTreeDataPart::FILE_FOR_REFERENCES_CHECK);
/// Temporary part with some absent file cannot be locked in shared mode
return std::make_pair(true, NameSet{});
}
if (part.getState() == MergeTreeDataPartState::Temporary && part.is_temp)
{
/// Part {} is in temporary state and has it_temp flag. it means that it is under construction.
/// That path hasn't been added to active set, no commit procedure has begun.
/// The metadata files is about to delete now. Clichouse has to make a decision remove or preserve blobs on remote FS.
/// In general remote data might be shared and has to be unlocked in the keeper before removing.
/// However there are some cases when decision is clear without asking keeper:
/// When the part has been fetched then remote data has to be preserved, part doesn't own it.
/// When the part has been merged then remote data can be removed, part owns it.
/// In opposition, when the part has been mutated in generally it hardlinks the files from source part.
/// Therefore remote data could be shared, it has to be unlocked in the keeper.
/// In order to track all that cases remove_tmp_policy is used.
/// Clickhouse set that field as REMOVE_BLOBS or PRESERVE_BLOBS when it sure about the decision without asking keeper.
if (part.remove_tmp_policy == IMergeTreeDataPart::BlobsRemovalPolicyForTemporaryParts::REMOVE_BLOBS
|| part.remove_tmp_policy == IMergeTreeDataPart::BlobsRemovalPolicyForTemporaryParts::PRESERVE_BLOBS)
{
bool can_remove_blobs = part.remove_tmp_policy == IMergeTreeDataPart::BlobsRemovalPolicyForTemporaryParts::REMOVE_BLOBS;
LOG_INFO(log, "Looks like CH knows the origin of that part. "
"Part {} can be deleted without unlocking shared data in zookeeper. "
"Part blobs {}.",
part.name,
can_remove_blobs ? "will be removed" : "have to be preserved");
return std::make_pair(can_remove_blobs, NameSet{});
}
}
if (has_metadata_in_zookeeper.has_value() && !has_metadata_in_zookeeper)
{
if (zookeeper->exists(zookeeper_path))
{
LOG_WARNING(log, "Not removing shared data for part {} because replica does not have metadata in ZooKeeper, "
"but table path exist and other replicas may exist. It may leave some garbage on S3", part.name);
return std::make_pair(false, NameSet{});
}
/// If table was completely dropped (no meta in zookeeper) we can safely remove parts
return std::make_pair(true, NameSet{});
}
/// We remove parts during table shutdown. If exception happen, restarting thread will be already turned
/// off and nobody will reconnect our zookeeper connection. In this case we use zookeeper connection from
/// context.
if (shutdown_called.load())
zookeeper->setKeeper(getZooKeeperIfTableShutDown());
else
zookeeper->setKeeper(getZooKeeper());
/// It can happen that we didn't had the connection to zookeeper during table creation, but actually
/// table is completely dropped, so we can drop it without any additional checks.
if (!has_metadata_in_zookeeper.has_value() && !zookeeper->exists(zookeeper_path))
return std::make_pair(true, NameSet{});
return unlockSharedDataByID(
part.getUniqueId(), shared_id, part.info, replica_name,
part.getDataPartStorage().getDiskType(), zookeeper, *getSettings(), log, zookeeper_path, format_version);
}
namespace
{
/// What is going on here?
/// Actually we need this code because of flaws in hardlinks tracking. When we create child part during mutation we can hardlink some files from parent part, like
/// all_0_0_0:
/// a.bin a.mrk2 columns.txt ...
/// all_0_0_0_1: ^ ^
/// a.bin a.mrk2 columns.txt
/// So when we deleting all_0_0_0 it doesn't remove blobs for a.bin and a.mrk2 because all_0_0_0_1 use them.
/// But sometimes we need an opposite. When we deleting all_0_0_0_1 it can be non replicated to other replicas, so we are the only owner of this part.
/// In this case when we will drop all_0_0_0_1 we will drop blobs for all_0_0_0. But it will lead to dataloss. For such case we need to check that other replicas
/// still need parent part.
std::pair<bool, std::optional<NameSet>> getParentLockedBlobs(const ZooKeeperWithFaultInjectionPtr & zookeeper_ptr, const std::string & zero_copy_part_path_prefix, const MergeTreePartInfo & part_info, MergeTreeDataFormatVersion format_version, Poco::Logger * log)
{
NameSet files_not_to_remove;
/// No mutations -- no hardlinks -- no issues
if (part_info.mutation == 0)
return {false, files_not_to_remove};
/// Getting all zero copy parts
Strings parts_str;
zookeeper_ptr->tryGetChildren(zero_copy_part_path_prefix, parts_str);
/// Parsing infos. It's hard to convert info -> string for old-format merge tree
/// so storing string as is.
std::vector<std::pair<MergeTreePartInfo, std::string>> parts_infos;
for (const auto & part_str : parts_str)
{
MergeTreePartInfo parent_candidate_info = MergeTreePartInfo::fromPartName(part_str, format_version);
parts_infos.emplace_back(parent_candidate_info, part_str);
}
/// Sort is important. We need to find our closest parent, like:
/// for part all_0_0_0_64 we can have parents
/// all_0_0_0_6 < we need the closest parent, not others
/// all_0_0_0_1
/// all_0_0_0
std::sort(parts_infos.begin(), parts_infos.end());
std::string part_info_str = part_info.getPartNameV1();
/// In reverse order to process from bigger to smaller
for (const auto & [parent_candidate_info, part_candidate_info_str] : parts_infos | std::views::reverse)
{
if (parent_candidate_info == part_info)
continue;
/// We are mutation child of this parent
if (part_info.isMutationChildOf(parent_candidate_info))
{
LOG_TRACE(log, "Found mutation parent {} for part {}", part_candidate_info_str, part_info_str);
/// Get hardlinked files
String files_not_to_remove_str;
Coordination::Error code;
zookeeper_ptr->tryGet(fs::path(zero_copy_part_path_prefix) / part_candidate_info_str, files_not_to_remove_str, nullptr, nullptr, &code);
if (code != Coordination::Error::ZOK)
{
LOG_TRACE(log, "Cannot get parent files from ZooKeeper on path ({}), error {}", (fs::path(zero_copy_part_path_prefix) / part_candidate_info_str).string(), code);
return {true, std::nullopt};
}
if (!files_not_to_remove_str.empty())
{
boost::split(files_not_to_remove, files_not_to_remove_str, boost::is_any_of("\n "));
LOG_TRACE(log, "Found files not to remove from parent part {}: [{}]", part_candidate_info_str, fmt::join(files_not_to_remove, ", "));
}
else
{
std::vector<std::string> children;
code = zookeeper_ptr->tryGetChildren(fs::path(zero_copy_part_path_prefix) / part_candidate_info_str, children);
if (code != Coordination::Error::ZOK)
{
LOG_TRACE(log, "Cannot get parent locks in ZooKeeper on path ({}), error {}", (fs::path(zero_copy_part_path_prefix) / part_candidate_info_str).string(), errorMessage(code));
return {true, std::nullopt};
}
if (children.size() > 1 || (children.size() == 1 && children[0] != ZeroCopyLock::ZERO_COPY_LOCK_NAME))
{
LOG_TRACE(log, "No files not to remove found for part {} from parent {}", part_info_str, part_candidate_info_str);
}
else
{
/// The case when part is actually removed, but some stale replica trying to execute merge/mutation.
/// We shouldn't use the part to check hardlinked blobs, it just doesn't exist.
LOG_TRACE(log, "Part {} is not parent (only merge/mutation locks exist), refusing to use as parent", part_candidate_info_str);
continue;
}
}
return {true, files_not_to_remove};
}
}
LOG_TRACE(log, "No mutation parent found for part {}", part_info_str);
return {false, files_not_to_remove};
}
}
std::pair<bool, NameSet> StorageReplicatedMergeTree::unlockSharedDataByID(
String part_id, const String & table_uuid, const MergeTreePartInfo & part_info,
const String & replica_name_, const std::string & disk_type, const ZooKeeperWithFaultInjectionPtr & zookeeper_ptr, const MergeTreeSettings & settings,
Poco::Logger * logger, const String & zookeeper_path_old, MergeTreeDataFormatVersion data_format_version)
{
boost::replace_all(part_id, "/", "_");
auto part_name = part_info.getPartNameV1();
Strings zc_zookeeper_paths = getZeroCopyPartPath(settings, disk_type, table_uuid, part_name, zookeeper_path_old);
bool part_has_no_more_locks = true;
NameSet files_not_to_remove;
for (const auto & zc_zookeeper_path : zc_zookeeper_paths)
{
String files_not_to_remove_str;
zookeeper_ptr->tryGet(zc_zookeeper_path, files_not_to_remove_str);
files_not_to_remove.clear();
if (!files_not_to_remove_str.empty())
boost::split(files_not_to_remove, files_not_to_remove_str, boost::is_any_of("\n "));
String zookeeper_part_uniq_node = fs::path(zc_zookeeper_path) / part_id;
/// Delete our replica node for part from zookeeper (we are not interested in it anymore)
String zookeeper_part_replica_node = fs::path(zookeeper_part_uniq_node) / replica_name_;
auto [has_parent, parent_not_to_remove] = getParentLockedBlobs(
zookeeper_ptr, fs::path(zc_zookeeper_path).parent_path(), part_info, data_format_version, logger);
// parent_not_to_remove == std::nullopt means that we were unable to retrieve parts set
if (has_parent || parent_not_to_remove == std::nullopt)
{
LOG_TRACE(logger, "Failed to get mutation parent on {} for part {}, refusing to remove blobs", zookeeper_part_replica_node, part_name);
return {false, {}};
}
files_not_to_remove.insert(parent_not_to_remove->begin(), parent_not_to_remove->end());
LOG_TRACE(logger, "Remove zookeeper lock {} for part {}", zookeeper_part_replica_node, part_name);
if (auto ec = zookeeper_ptr->tryRemove(zookeeper_part_replica_node); ec != Coordination::Error::ZOK)
{
/// Very complex case. It means that lock already doesn't exist when we tried to remove it.
/// So we don't know are we owner of this part or not. Maybe we just mutated it, renamed on disk and failed to lock in ZK.
/// But during mutation we can have hardlinks to another part. So it's not Ok to remove blobs of this part if it was mutated.
if (ec == Coordination::Error::ZNONODE)
{
if (has_parent)
{
LOG_INFO(logger, "Lock on path {} for part {} doesn't exist, refuse to remove blobs", zookeeper_part_replica_node, part_name);
return {false, {}};
}
else
{
LOG_INFO(logger, "Lock on path {} for part {} doesn't exist, but we don't have mutation parent, can remove blobs", zookeeper_part_replica_node, part_name);
}
}
else
{
throw zkutil::KeeperException::fromPath(ec, zookeeper_part_replica_node);
}
}
/// Check, maybe we were the last replica and can remove part forever
Strings children;
zookeeper_ptr->tryGetChildren(zookeeper_part_uniq_node, children);
if (!children.empty())
{
LOG_TRACE(logger, "Found {} ({}) zookeeper locks for {}", children.size(), fmt::join(children, ", "), zookeeper_part_uniq_node);
part_has_no_more_locks = false;
continue;
}
else
{
LOG_TRACE(logger, "No more children left for for {}, will try to remove the whole node", zookeeper_part_uniq_node);
}
auto error_code = zookeeper_ptr->tryRemove(zookeeper_part_uniq_node);
if (error_code == Coordination::Error::ZOK)
{
LOG_TRACE(logger, "Removed last parent zookeeper lock {} for part {} with id {}", zookeeper_part_uniq_node, part_name, part_id);
}
else if (error_code == Coordination::Error::ZNOTEMPTY)
{
LOG_TRACE(logger, "Cannot remove last parent zookeeper lock {} for part {} with id {}, another replica locked part concurrently", zookeeper_part_uniq_node, part_name, part_id);
}
else if (error_code == Coordination::Error::ZNONODE)
{
LOG_TRACE(logger, "Node with parent zookeeper lock {} for part {} with id {} doesn't exist", zookeeper_part_uniq_node, part_name, part_id);
}
else
{
throw zkutil::KeeperException::fromPath(error_code, zookeeper_part_uniq_node);
}
/// Even when we have lock with same part name, but with different uniq, we can remove files on S3
children.clear();
String zookeeper_part_node = fs::path(zookeeper_part_uniq_node).parent_path();
zookeeper_ptr->tryGetChildren(zookeeper_part_node, children);
if (children.empty())
{
/// Cleanup after last uniq removing
error_code = zookeeper_ptr->tryRemove(zookeeper_part_node);
if (error_code == Coordination::Error::ZOK)
{
LOG_TRACE(logger, "Removed last parent zookeeper lock {} for part {} (part is finally unlocked)", zookeeper_part_node, part_name);
}
else if (error_code == Coordination::Error::ZNOTEMPTY)
{
LOG_TRACE(logger, "Cannot remove last parent zookeeper lock {} for part {}, another replica locked part concurrently", zookeeper_part_uniq_node, part_name);
}
else if (error_code == Coordination::Error::ZNONODE)
{
/// We don't know what to do, because this part can be mutation part
/// with hardlinked columns. Since we don't have this information (about blobs not to remove)
/// we refuse to remove blobs.
LOG_WARNING(logger, "Node with parent zookeeper lock {} for part {} doesn't exist (part was unlocked before), refuse to remove blobs", zookeeper_part_uniq_node, part_name);
return {false, {}};
}
else
{
throw zkutil::KeeperException::fromPath(error_code, zookeeper_part_uniq_node);
}
}
else
{
LOG_TRACE(logger, "Can't remove parent zookeeper lock {} for part {}, because children {} ({}) exists",
zookeeper_part_node, part_name, children.size(), fmt::join(children, ", "));
}
}
return std::make_pair(part_has_no_more_locks, files_not_to_remove);
}
MergeTreeData::MutableDataPartPtr StorageReplicatedMergeTree::tryToFetchIfShared(
const IMergeTreeDataPart & part,
const DiskPtr & disk,
const String & path)
{
const auto settings = getSettings();
auto data_source_description = disk->getDataSourceDescription();
if (!(disk->supportZeroCopyReplication() && settings->allow_remote_fs_zero_copy_replication))
return nullptr;
String replica = getSharedDataReplica(part, data_source_description.type);
/// We can't fetch part when none replicas have this part on a same type remote disk
if (replica.empty())
return nullptr;
return executeFetchShared(replica, part.name, disk, path);
}
String StorageReplicatedMergeTree::getSharedDataReplica(
const IMergeTreeDataPart & part, DataSourceType data_source_type) const
{
String best_replica;
zkutil::ZooKeeperPtr zookeeper = tryGetZooKeeper();
if (!zookeeper)
return "";
Strings zc_zookeeper_paths = getZeroCopyPartPath(*getSettings(), toString(data_source_type), getTableSharedID(), part.name,
zookeeper_path);
std::set<String> replicas;
for (const auto & zc_zookeeper_path : zc_zookeeper_paths)
{
Strings ids;
zookeeper->tryGetChildren(zc_zookeeper_path, ids);
for (const auto & id : ids)
{
String zookeeper_part_uniq_node = fs::path(zc_zookeeper_path) / id;
Strings id_replicas;
zookeeper->tryGetChildren(zookeeper_part_uniq_node, id_replicas);
LOG_TRACE(log, "Found zookeeper replicas for {}: {}", zookeeper_part_uniq_node, id_replicas.size());
replicas.insert(id_replicas.begin(), id_replicas.end());
}
}
LOG_TRACE(log, "Found zookeeper replicas for part {}: {}", part.name, replicas.size());
Strings active_replicas;
/// TODO: Move best replica choose in common method (here is the same code as in StorageReplicatedMergeTree::fetchPartition)
/// Leave only active replicas.
active_replicas.reserve(replicas.size());
for (const String & replica : replicas)
if ((replica != replica_name) && (zookeeper->exists(fs::path(zookeeper_path) / "replicas" / replica / "is_active")))
active_replicas.push_back(replica);
LOG_TRACE(log, "Found zookeeper active replicas for part {}: {}", part.name, active_replicas.size());
if (active_replicas.empty())
return "";
/** You must select the best (most relevant) replica.
* This is a replica with the maximum `log_pointer`, then with the minimum `queue` size.
* NOTE This is not exactly the best criteria. It does not make sense to download old partitions,
* and it would be nice to be able to choose the replica closest by network.
* NOTE Of course, there are data races here. You can solve it by retrying.
*/
Int64 max_log_pointer = -1;
UInt64 min_queue_size = std::numeric_limits<UInt64>::max();
for (const String & replica : active_replicas)
{
String current_replica_path = fs::path(zookeeper_path) / "replicas" / replica;
String log_pointer_str = zookeeper->get(fs::path(current_replica_path) / "log_pointer");
Int64 log_pointer = log_pointer_str.empty() ? 0 : parse<UInt64>(log_pointer_str);
Coordination::Stat stat;
zookeeper->get(fs::path(current_replica_path) / "queue", &stat);
size_t queue_size = stat.numChildren;
if (log_pointer > max_log_pointer
|| (log_pointer == max_log_pointer && queue_size < min_queue_size))
{
max_log_pointer = log_pointer;
min_queue_size = queue_size;
best_replica = replica;
}
}
return best_replica;
}
Strings StorageReplicatedMergeTree::getZeroCopyPartPath(
const MergeTreeSettings & settings, const std::string & disk_type, const String & table_uuid,
const String & part_name, const String & zookeeper_path_old)
{
Strings res;
String zero_copy = fmt::format("zero_copy_{}", disk_type);
String new_path = fs::path(settings.remote_fs_zero_copy_zookeeper_path.toString()) / zero_copy / table_uuid / part_name;
res.push_back(std::move(new_path));
if (settings.remote_fs_zero_copy_path_compatible_mode && !zookeeper_path_old.empty())
{ /// Compatibility mode for cluster with old and new versions
String old_path = fs::path(zookeeper_path_old) / zero_copy / "shared" / part_name;
res.push_back(std::move(old_path));
}
return res;
}
void StorageReplicatedMergeTree::watchZeroCopyLock(const String & part_name, const DiskPtr & disk)
{
auto path = getZeroCopyPartPath(part_name, disk);
if (path)
{
auto zookeeper = getZooKeeper();
auto lock_path = fs::path(*path) / "part_exclusive_lock";
LOG_TEST(log, "Adding zero-copy lock on {}", lock_path);
/// Looks ugly, but we cannot touch any storage fields inside Watch callback
/// because it could lead to use-after-free (storage dropped and watch triggered)
std::shared_ptr<std::atomic<bool>> flag = std::make_shared<std::atomic<bool>>(true);
std::string replica;
bool exists = zookeeper->tryGetWatch(lock_path, replica, nullptr, [flag] (const Coordination::WatchResponse &)
{
*flag = false;
});
if (exists)
{
std::lock_guard lock(existing_zero_copy_locks_mutex);
existing_zero_copy_locks[lock_path] = ZeroCopyLockDescription{replica, flag};
}
}
}
bool StorageReplicatedMergeTree::checkZeroCopyLockExists(const String & part_name, const DiskPtr & disk, String & lock_replica)
{
auto path = getZeroCopyPartPath(part_name, disk);
std::lock_guard lock(existing_zero_copy_locks_mutex);
/// Cleanup abandoned locks during each check. The set of locks is small and this is quite fast loop.
/// Also it's hard to properly remove locks because we can execute replication queue
/// in arbitrary order and some parts can be replaced by covering parts without merges.
for (auto it = existing_zero_copy_locks.begin(); it != existing_zero_copy_locks.end();)
{
if (*it->second.exists)
++it;
else
{
LOG_TEST(log, "Removing zero-copy lock on {}", it->first);
it = existing_zero_copy_locks.erase(it);
}
}
if (path)
{
auto lock_path = fs::path(*path) / "part_exclusive_lock";
if (auto it = existing_zero_copy_locks.find(lock_path); it != existing_zero_copy_locks.end())
{
lock_replica = it->second.replica;
if (*it->second.exists)
{
LOG_TEST(log, "Zero-copy lock on path {} exists", it->first);
return true;
}
}
LOG_TEST(log, "Zero-copy lock on path {} doesn't exist", lock_path);
}
return false;
}
std::optional<String> StorageReplicatedMergeTree::getZeroCopyPartPath(const String & part_name, const DiskPtr & disk)
{
if (!disk || !disk->supportZeroCopyReplication())
return std::nullopt;
return getZeroCopyPartPath(*getSettings(), toString(disk->getDataSourceDescription().type), getTableSharedID(), part_name, zookeeper_path)[0];
}
bool StorageReplicatedMergeTree::waitZeroCopyLockToDisappear(const ZeroCopyLock & lock, size_t milliseconds_to_wait)
{
if (lock.isLocked())
return true;
if (partial_shutdown_called.load(std::memory_order_relaxed))
return true;
auto lock_path = lock.lock->getLockPath();
zkutil::ZooKeeperPtr zookeeper = tryGetZooKeeper();
if (!zookeeper)
return true;
Stopwatch time_waiting;
const auto & stop_waiting = [&]()
{
bool timeout_exceeded = milliseconds_to_wait < time_waiting.elapsedMilliseconds();
return partial_shutdown_called.load(std::memory_order_relaxed) || is_readonly.load(std::memory_order_relaxed) || timeout_exceeded;
};
return zookeeper->waitForDisappear(lock_path, stop_waiting);
}
std::optional<ZeroCopyLock> StorageReplicatedMergeTree::tryCreateZeroCopyExclusiveLock(const String & part_name, const DiskPtr & disk)
{
if (!disk || !disk->supportZeroCopyReplication())
return std::nullopt;
if (partial_shutdown_called.load(std::memory_order_relaxed) || is_readonly.load(std::memory_order_relaxed))
return std::nullopt;
zkutil::ZooKeeperPtr zookeeper = tryGetZooKeeper();
if (!zookeeper)
return std::nullopt;
String zc_zookeeper_path = *getZeroCopyPartPath(part_name, disk);
/// Just recursively create ancestors for lock
zookeeper->createAncestors(zc_zookeeper_path + "/");
/// Create actual lock
ZeroCopyLock lock(zookeeper, zc_zookeeper_path, replica_name);
lock.lock->tryLock();
return lock;
}
String StorageReplicatedMergeTree::findReplicaHavingPart(
const String & part_name, const String & zookeeper_path_, zkutil::ZooKeeper::Ptr zookeeper_ptr)
{
Strings replicas = zookeeper_ptr->getChildren(fs::path(zookeeper_path_) / "replicas");
/// Select replicas in uniformly random order.
std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
for (const String & replica : replicas)
{
if (zookeeper_ptr->exists(fs::path(zookeeper_path_) / "replicas" / replica / "parts" / part_name)
&& zookeeper_ptr->exists(fs::path(zookeeper_path_) / "replicas" / replica / "is_active"))
return fs::path(zookeeper_path_) / "replicas" / replica;
}
return {};
}
bool StorageReplicatedMergeTree::checkIfDetachedPartExists(const String & part_name)
{
fs::directory_iterator dir_end;
for (const std::string & path : getDataPaths())
for (fs::directory_iterator dir_it{fs::path(path) / "detached/"}; dir_it != dir_end; ++dir_it)
if (dir_it->path().filename().string() == part_name)
return true;
return false;
}
bool StorageReplicatedMergeTree::checkIfDetachedPartitionExists(const String & partition_name)
{
fs::directory_iterator dir_end;
for (const std::string & path : getDataPaths())
{
for (fs::directory_iterator dir_it{fs::path(path) / "detached/"}; dir_it != dir_end; ++dir_it)
{
const String file_name = dir_it->path().filename().string();
auto part_info = MergeTreePartInfo::tryParsePartName(file_name, format_version);
if (part_info && part_info->partition_id == partition_name)
return true;
}
}
return false;
}
bool StorageReplicatedMergeTree::createEmptyPartInsteadOfLost(zkutil::ZooKeeperPtr zookeeper, const String & lost_part_name)
{
LOG_INFO(log, "Going to replace lost part {} with empty part", lost_part_name);
auto new_part_info = MergeTreePartInfo::fromPartName(lost_part_name, format_version);
auto metadata_snapshot = getInMemoryMetadataPtr();
MergeTreePartition partition;
{
DataPartsLock lock = lockParts();
auto parts_in_partition = getDataPartsPartitionRange(new_part_info.partition_id);
if (!parts_in_partition.empty())
{
partition = (*parts_in_partition.begin())->partition;
}
else if (auto parsed_partition = MergeTreePartition::tryParseValueFromID(
new_part_info.partition_id,
metadata_snapshot->getPartitionKey().sample_block))
{
partition = MergeTreePartition(*parsed_partition);
}
else
{
LOG_WARNING(log, "Empty part {} is not created instead of lost part because there are no parts in partition {} (it's empty), "
"resolve this manually using DROP/DETACH PARTITION.", lost_part_name, new_part_info.partition_id);
return false;
}
}
auto [new_data_part, tmp_dir_holder] = createEmptyPart(new_part_info, partition, lost_part_name, NO_TRANSACTION_PTR);
new_data_part->setName(lost_part_name);
try
{
MergeTreeData::Transaction transaction(*this, NO_TRANSACTION_RAW);
auto replaced_parts = renameTempPartAndReplace(new_data_part, transaction);
if (!replaced_parts.empty())
{
Strings part_names;
for (const auto & part : replaced_parts)
part_names.emplace_back(part->name);
/// Why this exception is not a LOGICAL_ERROR? Because it's possible
/// to have some source parts for the lost part if replica currently
/// cloning from another replica, but source replica lost covering
/// part and finished MERGE_PARTS before clone. It's an extremely
/// rare case and it's unclear how to resolve it better. Eventually
/// source replica will replace lost part with empty part and we
/// will fetch this empty part instead of our source parts. This
/// will make replicas consistent, but some data will be lost.
throw Exception(ErrorCodes::INCORRECT_DATA,
"Tried to create empty part {}, but it replaces existing parts {}.",
lost_part_name, fmt::join(part_names, ", "));
}
lockSharedData(*new_data_part, false, {});
while (true)
{
/// We should be careful when creating an empty part, because we are not sure that this part is still needed.
/// For example, it's possible that part (or partition) was dropped (or replaced) concurrently.
/// We can enqueue part for check from DataPartExchange or SelectProcessor
/// and it's hard to synchronize it with ReplicatedMergeTreeQueue and PartCheckThread...
/// But at least we can ignore parts that are definitely not needed according to virtual parts and drop ranges.
auto pred = queue.getMergePredicate(zookeeper, PartitionIdsHint{new_part_info.partition_id});
String covering_virtual = pred.getCoveringVirtualPart(lost_part_name);
if (covering_virtual.empty())
{
LOG_WARNING(log, "Will not create empty part instead of lost {}, because there's no covering part in replication queue", lost_part_name);
return false;
}
MergeTreePartInfo drop_info;
if (pred.isGoingToBeDropped(MergeTreePartInfo::fromPartName(lost_part_name, format_version), &drop_info))
{
LOG_WARNING(log, "Will not create empty part instead of lost {}, "
"because it's going to be removed (by range {})",
lost_part_name, drop_info.getPartNameForLogs());
return false;
}
Coordination::Requests ops;
Coordination::Stat replicas_stat;
auto replicas_path = fs::path(zookeeper_path) / "replicas";
Strings replicas = zookeeper->getChildren(replicas_path, &replicas_stat);
ops.emplace_back(zkutil::makeCheckRequest(zookeeper_path + "/log", pred.getVersion()));
/// In rare cases new replica can appear during check
ops.emplace_back(zkutil::makeCheckRequest(replicas_path, replicas_stat.version));
for (const String & replica : replicas)
{
String current_part_path = fs::path(zookeeper_path) / "replicas" / replica / "parts" / lost_part_name;
/// We must be sure that this part doesn't exist on other replicas
if (!zookeeper->exists(current_part_path))
{
zkutil::addCheckNotExistsRequest(ops, *zookeeper, current_part_path);
}
else
{
throw Exception(ErrorCodes::DUPLICATE_DATA_PART,
"Part {} already exists on replica {} on path {}",
lost_part_name, replica, current_part_path);
}
}
getCommitPartOps(ops, new_data_part);
/// Increment lost_part_count
auto lost_part_count_path = fs::path(zookeeper_path) / "lost_part_count";
Coordination::Stat lost_part_count_stat;
String lost_part_count_str;
if (zookeeper->tryGet(lost_part_count_path, lost_part_count_str, &lost_part_count_stat))
{
UInt64 lost_part_count = lost_part_count_str.empty() ? 0 : parse<UInt64>(lost_part_count_str);
ops.emplace_back(zkutil::makeSetRequest(lost_part_count_path, toString(lost_part_count + 1), lost_part_count_stat.version));
}
else
{
ops.emplace_back(zkutil::makeCreateRequest(lost_part_count_path, "1", zkutil::CreateMode::Persistent));
}
Coordination::Responses responses;
if (auto code = zookeeper->tryMulti(ops, responses); code == Coordination::Error::ZOK)
{
transaction.commit();
break;
}
else if (code == Coordination::Error::ZBADVERSION)
{
LOG_INFO(log, "Looks like log was updated or new replica appeared while creating new empty part, will retry");
}
else
{
zkutil::KeeperMultiException::check(code, ops, responses);
}
}
}
catch (const Exception & ex)
{
LOG_WARNING(log, "Cannot commit empty part {} with error {}", lost_part_name, ex.displayText());
return false;
}
LOG_INFO(log, "Created empty part {} instead of lost part", lost_part_name);
return true;
}
void StorageReplicatedMergeTree::getZeroCopyLockNodeCreateOps(
const ZooKeeperWithFaultInjectionPtr & zookeeper, const String & zookeeper_node, Coordination::Requests & requests,
int32_t mode, bool replace_existing_lock,
const String & path_to_set_hardlinked_files, const NameSet & hardlinked_files)
{
/// Ephemeral locks can be created only when we fetch shared data.
/// So it never require to create ancestors. If we create them
/// race condition with source replica drop is possible.
if (mode == zkutil::CreateMode::Persistent)
zookeeper->checkExistsAndGetCreateAncestorsOps(zookeeper_node, requests);
if (replace_existing_lock && zookeeper->exists(zookeeper_node))
{
requests.emplace_back(zkutil::makeRemoveRequest(zookeeper_node, -1));
requests.emplace_back(zkutil::makeCreateRequest(zookeeper_node, "", mode));
if (!path_to_set_hardlinked_files.empty() && !hardlinked_files.empty())
{
std::string data = boost::algorithm::join(hardlinked_files, "\n");
/// List of files used to detect hardlinks. path_to_set_hardlinked_files --
/// is a path to source part zero copy node. During part removal hardlinked
/// files will be left for source part.
requests.emplace_back(zkutil::makeSetRequest(path_to_set_hardlinked_files, data, -1));
}
}
else
{
Coordination::Requests ops;
if (!path_to_set_hardlinked_files.empty() && !hardlinked_files.empty())
{
std::string data = boost::algorithm::join(hardlinked_files, "\n");
/// List of files used to detect hardlinks. path_to_set_hardlinked_files --
/// is a path to source part zero copy node. During part removal hardlinked
/// files will be left for source part.
requests.emplace_back(zkutil::makeSetRequest(path_to_set_hardlinked_files, data, -1));
}
requests.emplace_back(zkutil::makeCreateRequest(zookeeper_node, "", mode));
}
}
void StorageReplicatedMergeTree::createZeroCopyLockNode(
const ZooKeeperWithFaultInjectionPtr & zookeeper, const String & zookeeper_node, int32_t mode,
bool replace_existing_lock, const String & path_to_set_hardlinked_files, const NameSet & hardlinked_files)
{
/// In rare case other replica can remove path between createAncestors and createIfNotExists
/// So we make up to 5 attempts
bool created = false;
for (int attempts = 5; attempts > 0; --attempts)
{
Coordination::Requests ops;
Coordination::Responses responses;
getZeroCopyLockNodeCreateOps(zookeeper, zookeeper_node, ops, mode, replace_existing_lock, path_to_set_hardlinked_files, hardlinked_files);
auto error = zookeeper->tryMulti(ops, responses);
if (error == Coordination::Error::ZOK)
{
created = true;
break;
}
else if (mode == zkutil::CreateMode::Persistent)
{
if (error == Coordination::Error::ZNONODE)
continue;
if (error == Coordination::Error::ZNODEEXISTS)
{
size_t failed_op = zkutil::getFailedOpIndex(error, responses);
/// Part was locked before, unfortunately it's possible during moves
if (ops[failed_op]->getPath() == zookeeper_node)
{
created = true;
break;
}
continue;
}
}
else if (mode == zkutil::CreateMode::Ephemeral)
{
/// It is super rare case when we had part, but it was lost and we were unable to unlock it from keeper.
/// Now we are trying to fetch it from other replica and unlocking.
if (error == Coordination::Error::ZNODEEXISTS)
{
size_t failed_op = zkutil::getFailedOpIndex(error, responses);
if (ops[failed_op]->getPath() == zookeeper_node)
{
LOG_WARNING(&Poco::Logger::get("ZeroCopyLocks"), "Replacing persistent lock with ephemeral for path {}. It can happen only in case of local part loss", zookeeper_node);
replace_existing_lock = true;
continue;
}
}
}
zkutil::KeeperMultiException::check(error, ops, responses);
}
if (!created)
{
String mode_str = mode == zkutil::CreateMode::Persistent ? "persistent" : "ephemeral";
throw Exception(ErrorCodes::NOT_FOUND_NODE,
"Cannot create {} zero copy lock {} because part was unlocked from zookeeper",
mode_str, zookeeper_node);
}
}
bool StorageReplicatedMergeTree::removeDetachedPart(DiskPtr disk, const String & path, const String & part_name)
{
if (disk->supportZeroCopyReplication())
{
String table_id = getTableSharedID();
return removeSharedDetachedPart(disk, path, part_name, table_id, replica_name, zookeeper_path, getContext(), current_zookeeper);
}
disk->removeRecursive(path);
return false;
}
bool StorageReplicatedMergeTree::removeSharedDetachedPart(DiskPtr disk, const String & path, const String & part_name, const String & table_uuid,
const String & detached_replica_name, const String & detached_zookeeper_path, const ContextPtr & local_context, const zkutil::ZooKeeperPtr & zookeeper)
{
bool keep_shared = false;
NameSet files_not_to_remove;
// zero copy replication is only available since format version 1 so we can safely use it here
auto part_info = DetachedPartInfo::parseDetachedPartName(disk, part_name, MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING);
if (!part_info.valid_name)
throw Exception(ErrorCodes::BAD_DATA_PART_NAME, "Invalid detached part name {} on disk {}", path, disk->getName());
fs::path checksums = fs::path(path) / IMergeTreeDataPart::FILE_FOR_REFERENCES_CHECK;
if (disk->exists(checksums))
{
if (disk->getRefCount(checksums) == 0)
{
String id = disk->getUniqueId(checksums);
bool can_remove = false;
std::tie(can_remove, files_not_to_remove) = StorageReplicatedMergeTree::unlockSharedDataByID(
id, table_uuid, part_info,
detached_replica_name,
toString(disk->getDataSourceDescription().type),
std::make_shared<ZooKeeperWithFaultInjection>(zookeeper), local_context->getReplicatedMergeTreeSettings(),
&Poco::Logger::get("StorageReplicatedMergeTree"),
detached_zookeeper_path,
MERGE_TREE_DATA_MIN_FORMAT_VERSION_WITH_CUSTOM_PARTITIONING);
keep_shared = !can_remove;
}
else
keep_shared = true;
}
disk->removeSharedRecursive(path, keep_shared, files_not_to_remove);
return keep_shared;
}
void StorageReplicatedMergeTree::createAndStoreFreezeMetadata(DiskPtr disk, DataPartPtr, String backup_part_path) const
{
if (disk->supportZeroCopyReplication())
{
FreezeMetaData meta;
meta.fill(*this);
meta.save(disk, backup_part_path);
}
}
void StorageReplicatedMergeTree::adjustCreateQueryForBackup(ASTPtr & create_query) const
{
/// Adjust the create query using values from ZooKeeper.
auto zookeeper = getZooKeeper();
auto columns_from_entry = ColumnsDescription::parse(zookeeper->get(fs::path(zookeeper_path) / "columns"));
auto metadata_from_entry = ReplicatedMergeTreeTableMetadata::parse(zookeeper->get(fs::path(zookeeper_path) / "metadata"));
auto current_metadata = getInMemoryMetadataPtr();
auto metadata_diff = ReplicatedMergeTreeTableMetadata(*this, current_metadata).checkAndFindDiff(metadata_from_entry, current_metadata->getColumns(), getContext());
auto adjusted_metadata = metadata_diff.getNewMetadata(columns_from_entry, getContext(), *current_metadata);
applyMetadataChangesToCreateQuery(create_query, adjusted_metadata);
/// Check that tryGetTableSharedIDFromCreateQuery() works for this storage.
if (tryGetTableSharedIDFromCreateQuery(*create_query, getContext()) != getTableSharedID())
throw Exception(ErrorCodes::LOGICAL_ERROR, "Table {} has its shared ID to be different from one from the create query");
}
void StorageReplicatedMergeTree::backupData(
BackupEntriesCollector & backup_entries_collector, const String & data_path_in_backup, const std::optional<ASTs> & partitions)
{
/// First we generate backup entries in the same way as an ordinary MergeTree does.
/// But then we don't add them to the BackupEntriesCollector right away,
/// because we need to coordinate them with other replicas (other replicas can have better parts).
const auto & backup_settings = backup_entries_collector.getBackupSettings();
const auto & read_settings = backup_entries_collector.getReadSettings();
auto local_context = backup_entries_collector.getContext();
DataPartsVector data_parts;
if (partitions)
data_parts = getVisibleDataPartsVectorInPartitions(local_context, getPartitionIDsFromQuery(*partitions, local_context));
else
data_parts = getVisibleDataPartsVector(local_context);
auto parts_backup_entries = backupParts(data_parts, /* data_path_in_backup */ "", backup_settings, read_settings, local_context);
auto coordination = backup_entries_collector.getBackupCoordination();
String shared_id = getTableSharedID();
coordination->addReplicatedDataPath(shared_id, data_path_in_backup);
using PartNameAndChecksum = IBackupCoordination::PartNameAndChecksum;
std::vector<PartNameAndChecksum> part_names_with_hashes;
part_names_with_hashes.reserve(parts_backup_entries.size());
for (const auto & part_backup_entries : parts_backup_entries)
part_names_with_hashes.emplace_back(PartNameAndChecksum{part_backup_entries.part_name, part_backup_entries.part_checksum});
/// Send our list of part names to the coordination (to compare with other replicas).
coordination->addReplicatedPartNames(shared_id, getStorageID().getFullTableName(), getReplicaName(), part_names_with_hashes);
/// Send a list of mutations to the coordination too (we need to find the mutations which are not finished for added part names).
{
auto zookeeper = getZooKeeper();
Strings mutation_ids;
if (zookeeper->tryGetChildren(fs::path(zookeeper_path) / "mutations", mutation_ids) == Coordination::Error::ZOK)
{
std::vector<IBackupCoordination::MutationInfo> mutation_infos;
mutation_infos.reserve(mutation_ids.size());
for (const auto & mutation_id : mutation_ids)
{
String mutation;
if (zookeeper->tryGet(fs::path(zookeeper_path) / "mutations" / mutation_id, mutation))
mutation_infos.emplace_back(IBackupCoordination::MutationInfo{mutation_id, mutation});
}
coordination->addReplicatedMutations(shared_id, getStorageID().getFullTableName(), getReplicaName(), mutation_infos);
}
}
/// This task will be executed after all replicas have collected their parts and the coordination is ready to
/// give us the final list of parts to add to the BackupEntriesCollector.
auto post_collecting_task = [shared_id,
my_replica_name = getReplicaName(),
coordination,
my_parts_backup_entries = std::move(parts_backup_entries),
&backup_entries_collector]()
{
Strings data_paths = coordination->getReplicatedDataPaths(shared_id);
std::vector<fs::path> data_paths_fs;
data_paths_fs.reserve(data_paths.size());
for (const auto & data_path : data_paths)
data_paths_fs.push_back(data_path);
Strings part_names = coordination->getReplicatedPartNames(shared_id, my_replica_name);
std::unordered_set<std::string_view> part_names_set{part_names.begin(), part_names.end()};
for (const auto & part_backup_entries : my_parts_backup_entries)
{
if (part_names_set.contains(part_backup_entries.part_name))
{
for (const auto & [relative_path, backup_entry] : part_backup_entries.backup_entries)
for (const auto & data_path : data_paths_fs)
backup_entries_collector.addBackupEntry(data_path / relative_path, backup_entry);
}
}
auto mutation_infos = coordination->getReplicatedMutations(shared_id, my_replica_name);
for (const auto & mutation_info : mutation_infos)
{
auto backup_entry = ReplicatedMergeTreeMutationEntry::parse(mutation_info.entry, mutation_info.id).backup();
for (const auto & data_path : data_paths_fs)
backup_entries_collector.addBackupEntry(data_path / "mutations" / (mutation_info.id + ".txt"), backup_entry);
}
};
backup_entries_collector.addPostTask(post_collecting_task);
}
void StorageReplicatedMergeTree::restoreDataFromBackup(RestorerFromBackup & restorer, const String & data_path_in_backup, const std::optional<ASTs> & partitions)
{
String full_zk_path = getZooKeeperName() + getZooKeeperPath();
if (!restorer.getRestoreCoordination()->acquireInsertingDataIntoReplicatedTable(full_zk_path))
{
/// Other replica is already restoring the data of this table.
/// We'll get them later due to replication, it's not necessary to read it from the backup.
return;
}
if (!restorer.isNonEmptyTableAllowed())
{
bool empty = !getTotalActiveSizeInBytes();
if (empty)
{
/// New parts could be in the replication queue but not fetched yet.
/// In that case we consider the table as not empty.
ReplicatedTableStatus status;
getStatus(status, /* with_zk_fields = */ false);
if (status.queue.inserts_in_queue)
empty = false;
}
auto backup = restorer.getBackup();
if (!empty && backup->hasFiles(data_path_in_backup))
restorer.throwTableIsNotEmpty(getStorageID());
}
restorePartsFromBackup(restorer, data_path_in_backup, partitions);
}
void StorageReplicatedMergeTree::attachRestoredParts(MutableDataPartsVector && parts)
{
auto metadata_snapshot = getInMemoryMetadataPtr();
auto sink = std::make_shared<ReplicatedMergeTreeSink>(*this, metadata_snapshot, 0, 0, 0, false, false, false, getContext(), /*is_attach*/true);
for (auto part : parts)
sink->writeExistingPart(part);
}
template std::optional<EphemeralLockInZooKeeper> StorageReplicatedMergeTree::allocateBlockNumber<String>(
const String & partition_id,
const ZooKeeperWithFaultInjectionPtr & zookeeper,
const String & zookeeper_block_id_path,
const String & zookeeper_path_prefix) const;
template std::optional<EphemeralLockInZooKeeper> StorageReplicatedMergeTree::allocateBlockNumber<std::vector<String>>(
const String & partition_id,
const ZooKeeperWithFaultInjectionPtr & zookeeper,
const std::vector<String> & zookeeper_block_id_path,
const String & zookeeper_path_prefix) const;
}
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