ClickHouse/dbms/programs/copier/ClusterCopier.cpp
2020-02-19 18:01:08 +03:00

1381 lines
55 KiB
C++

#include "ClusterCopier.h"
#include "Internals.h"
#include <Common/ZooKeeper/ZooKeeper.h>
#include <Common/ZooKeeper/KeeperException.h>
namespace DB
{
void ClusterCopier::init()
{
auto zookeeper = context.getZooKeeper();
task_description_watch_callback = [this] (const Coordination::WatchResponse & response)
{
if (response.error != Coordination::ZOK)
return;
UInt64 version = ++task_descprtion_version;
LOG_DEBUG(log, "Task description should be updated, local version " << version);
};
task_description_path = task_zookeeper_path + "/description";
task_cluster = std::make_unique<TaskCluster>(task_zookeeper_path, working_database_name);
reloadTaskDescription();
task_cluster_initial_config = task_cluster_current_config;
task_cluster->loadTasks(*task_cluster_initial_config);
context.setClustersConfig(task_cluster_initial_config, task_cluster->clusters_prefix);
/// Set up shards and their priority
task_cluster->random_engine.seed(task_cluster->random_device());
for (auto & task_table : task_cluster->table_tasks)
{
task_table.cluster_pull = context.getCluster(task_table.cluster_pull_name);
task_table.cluster_push = context.getCluster(task_table.cluster_push_name);
task_table.initShards(task_cluster->random_engine);
}
LOG_DEBUG(log, "Will process " << task_cluster->table_tasks.size() << " table tasks");
/// Do not initialize tables, will make deferred initialization in process()
zookeeper->createAncestors(getWorkersPathVersion() + "/");
zookeeper->createAncestors(getWorkersPath() + "/");
}
template <typename T>
decltype(auto) ClusterCopier::retry(T && func, UInt64 max_tries)
{
std::exception_ptr exception;
for (UInt64 try_number = 1; try_number <= max_tries; ++try_number)
{
try
{
return func();
}
catch (...)
{
exception = std::current_exception();
if (try_number < max_tries)
{
tryLogCurrentException(log, "Will retry");
std::this_thread::sleep_for(default_sleep_time);
}
}
}
std::rethrow_exception(exception);
}
void ClusterCopier::discoverShardPartitions(const ConnectionTimeouts & timeouts, const TaskShardPtr & task_shard)
{
TaskTable & task_table = task_shard->task_table;
LOG_INFO(log, "Discover partitions of shard " << task_shard->getDescription());
auto get_partitions = [&] () { return getShardPartitions(timeouts, *task_shard); };
auto existing_partitions_names = retry(get_partitions, 60);
Strings filtered_partitions_names;
Strings missing_partitions;
/// Check that user specified correct partition names
auto check_partition_format = [] (const DataTypePtr & type, const String & partition_text_quoted)
{
MutableColumnPtr column_dummy = type->createColumn();
ReadBufferFromString rb(partition_text_quoted);
try
{
type->deserializeAsTextQuoted(*column_dummy, rb, FormatSettings());
}
catch (Exception & e)
{
throw Exception("Partition " + partition_text_quoted + " has incorrect format. " + e.displayText(), ErrorCodes::BAD_ARGUMENTS);
}
};
if (task_table.has_enabled_partitions)
{
/// Process partition in order specified by <enabled_partitions/>
for (const String & partition_name : task_table.enabled_partitions)
{
/// Check that user specified correct partition names
check_partition_format(task_shard->partition_key_column.type, partition_name);
auto it = existing_partitions_names.find(partition_name);
/// Do not process partition if it is not in enabled_partitions list
if (it == existing_partitions_names.end())
{
missing_partitions.emplace_back(partition_name);
continue;
}
filtered_partitions_names.emplace_back(*it);
}
for (const String & partition_name : existing_partitions_names)
{
if (!task_table.enabled_partitions_set.count(partition_name))
{
LOG_DEBUG(log, "Partition " << partition_name << " will not be processed, since it is not in "
<< "enabled_partitions of " << task_table.table_id);
}
}
}
else
{
for (const String & partition_name : existing_partitions_names)
filtered_partitions_names.emplace_back(partition_name);
}
for (const String & partition_name : filtered_partitions_names)
{
task_shard->partition_tasks.emplace(partition_name, ShardPartition(*task_shard, partition_name));
task_shard->checked_partitions.emplace(partition_name, true);
}
if (!missing_partitions.empty())
{
std::stringstream ss;
for (const String & missing_partition : missing_partitions)
ss << " " << missing_partition;
LOG_WARNING(log, "There are no " << missing_partitions.size() << " partitions from enabled_partitions in shard "
<< task_shard->getDescription() << " :" << ss.str());
}
LOG_DEBUG(log, "Will copy " << task_shard->partition_tasks.size() << " partitions from shard " << task_shard->getDescription());
}
void ClusterCopier::discoverTablePartitions(const ConnectionTimeouts & timeouts, TaskTable & task_table, UInt64 num_threads)
{
/// Fetch partitions list from a shard
{
ThreadPool thread_pool(num_threads ? num_threads : 2 * getNumberOfPhysicalCPUCores());
for (const TaskShardPtr & task_shard : task_table.all_shards)
thread_pool.scheduleOrThrowOnError([this, timeouts, task_shard]() { discoverShardPartitions(timeouts, task_shard); });
LOG_DEBUG(log, "Waiting for " << thread_pool.active() << " setup jobs");
thread_pool.wait();
}
}
void ClusterCopier::uploadTaskDescription(const std::string & task_path, const std::string & task_file, const bool force)
{
auto local_task_description_path = task_path + "/description";
String task_config_str;
{
ReadBufferFromFile in(task_file);
readStringUntilEOF(task_config_str, in);
}
if (task_config_str.empty())
return;
auto zookeeper = context.getZooKeeper();
zookeeper->createAncestors(local_task_description_path);
auto code = zookeeper->tryCreate(local_task_description_path, task_config_str, zkutil::CreateMode::Persistent);
if (code && force)
zookeeper->createOrUpdate(local_task_description_path, task_config_str, zkutil::CreateMode::Persistent);
LOG_DEBUG(log, "Task description " << ((code && !force) ? "not " : "") << "uploaded to " << local_task_description_path << " with result " << code << " ("<< zookeeper->error2string(code) << ")");
}
void ClusterCopier::reloadTaskDescription()
{
auto zookeeper = context.getZooKeeper();
task_description_watch_zookeeper = zookeeper;
String task_config_str;
Coordination::Stat stat;
int code;
zookeeper->tryGetWatch(task_description_path, task_config_str, &stat, task_description_watch_callback, &code);
if (code)
throw Exception("Can't get description node " + task_description_path, ErrorCodes::BAD_ARGUMENTS);
LOG_DEBUG(log, "Loading description, zxid=" << task_descprtion_current_stat.czxid);
auto config = getConfigurationFromXMLString(task_config_str);
/// Setup settings
task_cluster->reloadSettings(*config);
context.getSettingsRef() = task_cluster->settings_common;
task_cluster_current_config = config;
task_descprtion_current_stat = stat;
}
void ClusterCopier::updateConfigIfNeeded()
{
UInt64 version_to_update = task_descprtion_version;
bool is_outdated_version = task_descprtion_current_version != version_to_update;
bool is_expired_session = !task_description_watch_zookeeper || task_description_watch_zookeeper->expired();
if (!is_outdated_version && !is_expired_session)
return;
LOG_DEBUG(log, "Updating task description");
reloadTaskDescription();
task_descprtion_current_version = version_to_update;
}
void ClusterCopier::process(const ConnectionTimeouts & timeouts)
{
for (TaskTable & task_table : task_cluster->table_tasks)
{
LOG_INFO(log, "Process table task " << task_table.table_id << " with "
<< task_table.all_shards.size() << " shards, " << task_table.local_shards.size() << " of them are local ones");
if (task_table.all_shards.empty())
continue;
/// Discover partitions of each shard and total set of partitions
if (!task_table.has_enabled_partitions)
{
/// If there are no specified enabled_partitions, we must discover them manually
discoverTablePartitions(timeouts, task_table);
/// After partitions of each shard are initialized, initialize cluster partitions
for (const TaskShardPtr & task_shard : task_table.all_shards)
{
for (const auto & partition_elem : task_shard->partition_tasks)
{
const String & partition_name = partition_elem.first;
task_table.cluster_partitions.emplace(partition_name, ClusterPartition{});
}
}
for (auto & partition_elem : task_table.cluster_partitions)
{
const String & partition_name = partition_elem.first;
for (const TaskShardPtr & task_shard : task_table.all_shards)
task_shard->checked_partitions.emplace(partition_name);
task_table.ordered_partition_names.emplace_back(partition_name);
}
}
else
{
/// If enabled_partitions are specified, assume that each shard has all partitions
/// We will refine partition set of each shard in future
for (const String & partition_name : task_table.enabled_partitions)
{
task_table.cluster_partitions.emplace(partition_name, ClusterPartition{});
task_table.ordered_partition_names.emplace_back(partition_name);
}
}
task_table.watch.restart();
/// Retry table processing
bool table_is_done = false;
for (UInt64 num_table_tries = 0; num_table_tries < max_table_tries; ++num_table_tries)
{
if (tryProcessTable(timeouts, task_table))
{
table_is_done = true;
break;
}
}
if (!table_is_done)
{
throw Exception("Too many tries to process table " + task_table.table_id + ". Abort remaining execution",
ErrorCodes::UNFINISHED);
}
}
}
/// Protected section
zkutil::EphemeralNodeHolder::Ptr ClusterCopier::createTaskWorkerNodeAndWaitIfNeed(
const zkutil::ZooKeeperPtr & zookeeper,
const String & description,
bool unprioritized)
{
std::chrono::milliseconds current_sleep_time = default_sleep_time;
static constexpr std::chrono::milliseconds max_sleep_time(30000); // 30 sec
if (unprioritized)
std::this_thread::sleep_for(current_sleep_time);
String workers_version_path = getWorkersPathVersion();
String workers_path = getWorkersPath();
String current_worker_path = getCurrentWorkerNodePath();
UInt64 num_bad_version_errors = 0;
while (true)
{
updateConfigIfNeeded();
Coordination::Stat stat;
zookeeper->get(workers_version_path, &stat);
auto version = stat.version;
zookeeper->get(workers_path, &stat);
if (static_cast<UInt64>(stat.numChildren) >= task_cluster->max_workers)
{
LOG_DEBUG(log, "Too many workers (" << stat.numChildren << ", maximum " << task_cluster->max_workers << ")"
<< ". Postpone processing " << description);
if (unprioritized)
current_sleep_time = std::min(max_sleep_time, current_sleep_time + default_sleep_time);
std::this_thread::sleep_for(current_sleep_time);
num_bad_version_errors = 0;
}
else
{
Coordination::Requests ops;
ops.emplace_back(zkutil::makeSetRequest(workers_version_path, description, version));
ops.emplace_back(zkutil::makeCreateRequest(current_worker_path, description, zkutil::CreateMode::Ephemeral));
Coordination::Responses responses;
auto code = zookeeper->tryMulti(ops, responses);
if (code == Coordination::ZOK || code == Coordination::ZNODEEXISTS)
return std::make_shared<zkutil::EphemeralNodeHolder>(current_worker_path, *zookeeper, false, false, description);
if (code == Coordination::ZBADVERSION)
{
++num_bad_version_errors;
/// Try to make fast retries
if (num_bad_version_errors > 3)
{
LOG_DEBUG(log, "A concurrent worker has just been added, will check free worker slots again");
std::chrono::milliseconds random_sleep_time(std::uniform_int_distribution<int>(1, 1000)(task_cluster->random_engine));
std::this_thread::sleep_for(random_sleep_time);
num_bad_version_errors = 0;
}
}
else
throw Coordination::Exception(code);
}
}
}
/** Checks that the whole partition of a table was copied. We should do it carefully due to dirty lock.
* State of some task could change during the processing.
* We have to ensure that all shards have the finished state and there is no dirty flag.
* Moreover, we have to check status twice and check zxid, because state can change during the checking.
*/
bool ClusterCopier::checkPartitionIsDone(const TaskTable & task_table, const String & partition_name, const TasksShard & shards_with_partition)
{
LOG_DEBUG(log, "Check that all shards processed partition " << partition_name << " successfully");
auto zookeeper = context.getZooKeeper();
Strings status_paths;
for (auto & shard : shards_with_partition)
{
ShardPartition & task_shard_partition = shard->partition_tasks.find(partition_name)->second;
status_paths.emplace_back(task_shard_partition.getShardStatusPath());
}
std::vector<int64_t> zxid1, zxid2;
try
{
std::vector<zkutil::ZooKeeper::FutureGet> get_futures;
for (const String & path : status_paths)
get_futures.emplace_back(zookeeper->asyncGet(path));
// Check that state is Finished and remember zxid
for (auto & future : get_futures)
{
auto res = future.get();
TaskStateWithOwner status = TaskStateWithOwner::fromString(res.data);
if (status.state != TaskState::Finished)
{
LOG_INFO(log, "The task " << res.data << " is being rewritten by " << status.owner << ". Partition will be rechecked");
return false;
}
zxid1.push_back(res.stat.pzxid);
}
// Check that partition is not dirty
{
CleanStateClock clean_state_clock (
zookeeper,
task_table.getPartitionIsDirtyPath(partition_name),
task_table.getPartitionIsCleanedPath(partition_name)
);
Coordination::Stat stat;
LogicalClock task_start_clock;
if (zookeeper->exists(task_table.getPartitionTaskStatusPath(partition_name), &stat))
task_start_clock = LogicalClock(stat.mzxid);
zookeeper->get(task_table.getPartitionTaskStatusPath(partition_name), &stat);
if (!clean_state_clock.is_clean() || task_start_clock <= clean_state_clock.discovery_zxid)
{
LOG_INFO(log, "Partition " << partition_name << " become dirty");
return false;
}
}
get_futures.clear();
for (const String & path : status_paths)
get_futures.emplace_back(zookeeper->asyncGet(path));
// Remember zxid of states again
for (auto & future : get_futures)
{
auto res = future.get();
zxid2.push_back(res.stat.pzxid);
}
}
catch (const Coordination::Exception & e)
{
LOG_INFO(log, "A ZooKeeper error occurred while checking partition " << partition_name
<< ". Will recheck the partition. Error: " << e.displayText());
return false;
}
// If all task is finished and zxid is not changed then partition could not become dirty again
for (UInt64 shard_num = 0; shard_num < status_paths.size(); ++shard_num)
{
if (zxid1[shard_num] != zxid2[shard_num])
{
LOG_INFO(log, "The task " << status_paths[shard_num] << " is being modified now. Partition will be rechecked");
return false;
}
}
LOG_INFO(log, "Partition " << partition_name << " is copied successfully");
return true;
}
ASTPtr ClusterCopier::removeAliasColumnsFromCreateQuery(const ASTPtr & query_ast)
{
const ASTs & column_asts = query_ast->as<ASTCreateQuery &>().columns_list->columns->children;
auto new_columns = std::make_shared<ASTExpressionList>();
for (const ASTPtr & column_ast : column_asts)
{
const auto & column = column_ast->as<ASTColumnDeclaration &>();
if (!column.default_specifier.empty())
{
ColumnDefaultKind kind = columnDefaultKindFromString(column.default_specifier);
if (kind == ColumnDefaultKind::Materialized || kind == ColumnDefaultKind::Alias)
continue;
}
new_columns->children.emplace_back(column_ast->clone());
}
ASTPtr new_query_ast = query_ast->clone();
auto & new_query = new_query_ast->as<ASTCreateQuery &>();
auto new_columns_list = std::make_shared<ASTColumns>();
new_columns_list->set(new_columns_list->columns, new_columns);
if (auto indices = query_ast->as<ASTCreateQuery>()->columns_list->indices)
new_columns_list->set(new_columns_list->indices, indices->clone());
new_query.replace(new_query.columns_list, new_columns_list);
return new_query_ast;
}
std::shared_ptr<ASTCreateQuery> ClusterCopier::rewriteCreateQueryStorage(const ASTPtr & create_query_ast, const DatabaseAndTableName & new_table, const ASTPtr & new_storage_ast)
{
const auto & create = create_query_ast->as<ASTCreateQuery &>();
auto res = std::make_shared<ASTCreateQuery>(create);
if (create.storage == nullptr || new_storage_ast == nullptr)
throw Exception("Storage is not specified", ErrorCodes::LOGICAL_ERROR);
res->database = new_table.first;
res->table = new_table.second;
res->children.clear();
res->set(res->columns_list, create.columns_list->clone());
res->set(res->storage, new_storage_ast->clone());
return res;
}
bool ClusterCopier::tryDropPartition(ShardPartition & task_partition, const zkutil::ZooKeeperPtr & zookeeper, const CleanStateClock & clean_state_clock)
{
if (is_safe_mode)
throw Exception("DROP PARTITION is prohibited in safe mode", ErrorCodes::NOT_IMPLEMENTED);
TaskTable & task_table = task_partition.task_shard.task_table;
const String current_shards_path = task_partition.getPartitionShardsPath();
const String current_partition_active_workers_dir = task_partition.getPartitionActiveWorkersPath();
const String is_dirty_flag_path = task_partition.getCommonPartitionIsDirtyPath();
const String dirt_cleaner_path = is_dirty_flag_path + "/cleaner";
const String is_dirt_cleaned_path = task_partition.getCommonPartitionIsCleanedPath();
zkutil::EphemeralNodeHolder::Ptr cleaner_holder;
try
{
cleaner_holder = zkutil::EphemeralNodeHolder::create(dirt_cleaner_path, *zookeeper, host_id);
}
catch (const Coordination::Exception & e)
{
if (e.code == Coordination::ZNODEEXISTS)
{
LOG_DEBUG(log, "Partition " << task_partition.name << " is cleaning now by somebody, sleep");
std::this_thread::sleep_for(default_sleep_time);
return false;
}
throw;
}
Coordination::Stat stat;
if (zookeeper->exists(current_partition_active_workers_dir, &stat))
{
if (stat.numChildren != 0)
{
LOG_DEBUG(log, "Partition " << task_partition.name << " contains " << stat.numChildren << " active workers while trying to drop it. Going to sleep.");
std::this_thread::sleep_for(default_sleep_time);
return false;
}
else
{
zookeeper->remove(current_partition_active_workers_dir);
}
}
{
zkutil::EphemeralNodeHolder::Ptr active_workers_lock;
try
{
active_workers_lock = zkutil::EphemeralNodeHolder::create(current_partition_active_workers_dir, *zookeeper, host_id);
}
catch (const Coordination::Exception & e)
{
if (e.code == Coordination::ZNODEEXISTS)
{
LOG_DEBUG(log, "Partition " << task_partition.name << " is being filled now by somebody, sleep");
return false;
}
throw;
}
// Lock the dirty flag
zookeeper->set(is_dirty_flag_path, host_id, clean_state_clock.discovery_version.value());
zookeeper->tryRemove(task_partition.getPartitionCleanStartPath());
CleanStateClock my_clock(zookeeper, is_dirty_flag_path, is_dirt_cleaned_path);
/// Remove all status nodes
{
Strings children;
if (zookeeper->tryGetChildren(current_shards_path, children) == Coordination::ZOK)
for (const auto & child : children)
{
zookeeper->removeRecursive(current_shards_path + "/" + child);
}
}
String query = "ALTER TABLE " + getQuotedTable(task_table.table_push);
query += " DROP PARTITION " + task_partition.name + "";
/// TODO: use this statement after servers will be updated up to 1.1.54310
// query += " DROP PARTITION ID '" + task_partition.name + "'";
ClusterPtr & cluster_push = task_table.cluster_push;
Settings settings_push = task_cluster->settings_push;
/// It is important, DROP PARTITION must be done synchronously
settings_push.replication_alter_partitions_sync = 2;
LOG_DEBUG(log, "Execute distributed DROP PARTITION: " << query);
/// Limit number of max executing replicas to 1
UInt64 num_shards = executeQueryOnCluster(cluster_push, query, nullptr, &settings_push, PoolMode::GET_ONE, 1);
if (num_shards < cluster_push->getShardCount())
{
LOG_INFO(log, "DROP PARTITION wasn't successfully executed on " << cluster_push->getShardCount() - num_shards << " shards");
return false;
}
/// Update the locking node
if (!my_clock.is_stale())
{
zookeeper->set(is_dirty_flag_path, host_id, my_clock.discovery_version.value());
if (my_clock.clean_state_version)
zookeeper->set(is_dirt_cleaned_path, host_id, my_clock.clean_state_version.value());
else
zookeeper->create(is_dirt_cleaned_path, host_id, zkutil::CreateMode::Persistent);
}
else
{
LOG_DEBUG(log, "Clean state is altered when dropping the partition, cowardly bailing");
/// clean state is stale
return false;
}
LOG_INFO(log, "Partition " << task_partition.name << " was dropped on cluster " << task_table.cluster_push_name);
if (zookeeper->tryCreate(current_shards_path, host_id, zkutil::CreateMode::Persistent) == Coordination::ZNODEEXISTS)
zookeeper->set(current_shards_path, host_id);
}
LOG_INFO(log, "Partition " << task_partition.name << " is safe for work now.");
return true;
}
bool ClusterCopier::tryProcessTable(const ConnectionTimeouts & timeouts, TaskTable & task_table)
{
/// An heuristic: if previous shard is already done, then check next one without sleeps due to max_workers constraint
bool previous_shard_is_instantly_finished = false;
/// Process each partition that is present in cluster
for (const String & partition_name : task_table.ordered_partition_names)
{
if (!task_table.cluster_partitions.count(partition_name))
throw Exception("There are no expected partition " + partition_name + ". It is a bug", ErrorCodes::LOGICAL_ERROR);
ClusterPartition & cluster_partition = task_table.cluster_partitions[partition_name];
Stopwatch watch;
TasksShard expected_shards;
UInt64 num_failed_shards = 0;
++cluster_partition.total_tries;
LOG_DEBUG(log, "Processing partition " << partition_name << " for the whole cluster");
/// Process each source shard having current partition and copy current partition
/// NOTE: shards are sorted by "distance" to current host
bool has_shard_to_process = false;
for (const TaskShardPtr & shard : task_table.all_shards)
{
/// Does shard have a node with current partition?
if (shard->partition_tasks.count(partition_name) == 0)
{
/// If not, did we check existence of that partition previously?
if (shard->checked_partitions.count(partition_name) == 0)
{
auto check_shard_has_partition = [&] () { return checkShardHasPartition(timeouts, *shard, partition_name); };
bool has_partition = retry(check_shard_has_partition);
shard->checked_partitions.emplace(partition_name);
if (has_partition)
{
shard->partition_tasks.emplace(partition_name, ShardPartition(*shard, partition_name));
LOG_DEBUG(log, "Discovered partition " << partition_name << " in shard " << shard->getDescription());
}
else
{
LOG_DEBUG(log, "Found that shard " << shard->getDescription() << " does not contain current partition " << partition_name);
continue;
}
}
else
{
/// We have already checked that partition, but did not discover it
previous_shard_is_instantly_finished = true;
continue;
}
}
auto it_shard_partition = shard->partition_tasks.find(partition_name);
if (it_shard_partition == shard->partition_tasks.end())
throw Exception("There are no such partition in a shard. This is a bug.", ErrorCodes::LOGICAL_ERROR);
auto & partition = it_shard_partition->second;
expected_shards.emplace_back(shard);
/// Do not sleep if there is a sequence of already processed shards to increase startup
bool is_unprioritized_task = !previous_shard_is_instantly_finished && shard->priority.is_remote;
PartitionTaskStatus task_status = PartitionTaskStatus::Error;
bool was_error = false;
has_shard_to_process = true;
for (UInt64 try_num = 0; try_num < max_shard_partition_tries; ++try_num)
{
task_status = tryProcessPartitionTask(timeouts, partition, is_unprioritized_task);
/// Exit if success
if (task_status == PartitionTaskStatus::Finished)
break;
was_error = true;
/// Skip if the task is being processed by someone
if (task_status == PartitionTaskStatus::Active)
break;
/// Repeat on errors
std::this_thread::sleep_for(default_sleep_time);
}
if (task_status == PartitionTaskStatus::Error)
++num_failed_shards;
previous_shard_is_instantly_finished = !was_error;
}
cluster_partition.elapsed_time_seconds += watch.elapsedSeconds();
/// Check that whole cluster partition is done
/// Firstly check the number of failed partition tasks, then look into ZooKeeper and ensure that each partition is done
bool partition_is_done = num_failed_shards == 0;
try
{
partition_is_done =
!has_shard_to_process
|| (partition_is_done && checkPartitionIsDone(task_table, partition_name, expected_shards));
}
catch (...)
{
tryLogCurrentException(log);
partition_is_done = false;
}
if (partition_is_done)
{
task_table.finished_cluster_partitions.emplace(partition_name);
task_table.bytes_copied += cluster_partition.bytes_copied;
task_table.rows_copied += cluster_partition.rows_copied;
double elapsed = cluster_partition.elapsed_time_seconds;
LOG_INFO(log, "It took " << std::fixed << std::setprecision(2) << elapsed << " seconds to copy partition " << partition_name
<< ": " << formatReadableSizeWithDecimalSuffix(cluster_partition.bytes_copied) << " uncompressed bytes"
<< ", " << formatReadableQuantity(cluster_partition.rows_copied) << " rows"
<< " and " << cluster_partition.blocks_copied << " source blocks are copied");
if (cluster_partition.rows_copied)
{
LOG_INFO(log, "Average partition speed: "
<< formatReadableSizeWithDecimalSuffix(cluster_partition.bytes_copied / elapsed) << " per second.");
}
if (task_table.rows_copied)
{
LOG_INFO(log, "Average table " << task_table.table_id << " speed: "
<< formatReadableSizeWithDecimalSuffix(task_table.bytes_copied / elapsed) << " per second.");
}
}
}
UInt64 required_partitions = task_table.cluster_partitions.size();
UInt64 finished_partitions = task_table.finished_cluster_partitions.size();
bool table_is_done = finished_partitions >= required_partitions;
if (!table_is_done)
{
LOG_INFO(log, "Table " + task_table.table_id + " is not processed yet."
<< "Copied " << finished_partitions << " of " << required_partitions << ", will retry");
}
return table_is_done;
}
PartitionTaskStatus ClusterCopier::tryProcessPartitionTask(const ConnectionTimeouts & timeouts, ShardPartition & task_partition, bool is_unprioritized_task)
{
PartitionTaskStatus res;
try
{
res = processPartitionTaskImpl(timeouts, task_partition, is_unprioritized_task);
}
catch (...)
{
tryLogCurrentException(log, "An error occurred while processing partition " + task_partition.name);
res = PartitionTaskStatus::Error;
}
/// At the end of each task check if the config is updated
try
{
updateConfigIfNeeded();
}
catch (...)
{
tryLogCurrentException(log, "An error occurred while updating the config");
}
return res;
}
PartitionTaskStatus ClusterCopier::processPartitionTaskImpl(const ConnectionTimeouts & timeouts, ShardPartition & task_partition, bool is_unprioritized_task)
{
TaskShard & task_shard = task_partition.task_shard;
TaskTable & task_table = task_shard.task_table;
ClusterPartition & cluster_partition = task_table.getClusterPartition(task_partition.name);
/// We need to update table definitions for each partition, it could be changed after ALTER
createShardInternalTables(timeouts, task_shard);
auto zookeeper = context.getZooKeeper();
const String is_dirty_flag_path = task_partition.getCommonPartitionIsDirtyPath();
const String is_dirt_cleaned_path = task_partition.getCommonPartitionIsCleanedPath();
const String current_task_is_active_path = task_partition.getActiveWorkerPath();
const String current_task_status_path = task_partition.getShardStatusPath();
/// Auxiliary functions:
/// Creates is_dirty node to initialize DROP PARTITION
auto create_is_dirty_node = [&, this] (const CleanStateClock & clock)
{
if (clock.is_stale())
LOG_DEBUG(log, "Clean state clock is stale while setting dirty flag, cowardly bailing");
else if (!clock.is_clean())
LOG_DEBUG(log, "Thank you, Captain Obvious");
else if (clock.discovery_version)
{
LOG_DEBUG(log, "Updating clean state clock");
zookeeper->set(is_dirty_flag_path, host_id, clock.discovery_version.value());
}
else
{
LOG_DEBUG(log, "Creating clean state clock");
zookeeper->create(is_dirty_flag_path, host_id, zkutil::CreateMode::Persistent);
}
};
/// Returns SELECT query filtering current partition and applying user filter
auto get_select_query = [&] (const DatabaseAndTableName & from_table, const String & fields, String limit = "")
{
String query;
query += "SELECT " + fields + " FROM " + getQuotedTable(from_table);
/// TODO: Bad, it is better to rewrite with ASTLiteral(partition_key_field)
query += " WHERE (" + queryToString(task_table.engine_push_partition_key_ast) + " = (" + task_partition.name + " AS partition_key))";
if (!task_table.where_condition_str.empty())
query += " AND (" + task_table.where_condition_str + ")";
if (!limit.empty())
query += " LIMIT " + limit;
ParserQuery p_query(query.data() + query.size());
return parseQuery(p_query, query, 0);
};
/// Load balancing
auto worker_node_holder = createTaskWorkerNodeAndWaitIfNeed(zookeeper, current_task_status_path, is_unprioritized_task);
LOG_DEBUG(log, "Processing " << current_task_status_path);
CleanStateClock clean_state_clock (zookeeper, is_dirty_flag_path, is_dirt_cleaned_path);
LogicalClock task_start_clock;
{
Coordination::Stat stat;
if (zookeeper->exists(task_partition.getPartitionShardsPath(), &stat))
task_start_clock = LogicalClock(stat.mzxid);
}
/// Do not start if partition is dirty, try to clean it
if (clean_state_clock.is_clean()
&& (!task_start_clock.hasHappened() || clean_state_clock.discovery_zxid <= task_start_clock))
{
LOG_DEBUG(log, "Partition " << task_partition.name << " appears to be clean");
zookeeper->createAncestors(current_task_status_path);
}
else
{
LOG_DEBUG(log, "Partition " << task_partition.name << " is dirty, try to drop it");
try
{
tryDropPartition(task_partition, zookeeper, clean_state_clock);
}
catch (...)
{
tryLogCurrentException(log, "An error occurred when clean partition");
}
return PartitionTaskStatus::Error;
}
/// Create ephemeral node to mark that we are active and process the partition
zookeeper->createAncestors(current_task_is_active_path);
zkutil::EphemeralNodeHolderPtr partition_task_node_holder;
try
{
partition_task_node_holder = zkutil::EphemeralNodeHolder::create(current_task_is_active_path, *zookeeper, host_id);
}
catch (const Coordination::Exception & e)
{
if (e.code == Coordination::ZNODEEXISTS)
{
LOG_DEBUG(log, "Someone is already processing " << current_task_is_active_path);
return PartitionTaskStatus::Active;
}
throw;
}
/// Exit if task has been already processed;
/// create blocking node to signal cleaning up if it is abandoned
{
String status_data;
if (zookeeper->tryGet(current_task_status_path, status_data))
{
TaskStateWithOwner status = TaskStateWithOwner::fromString(status_data);
if (status.state == TaskState::Finished)
{
LOG_DEBUG(log, "Task " << current_task_status_path << " has been successfully executed by " << status.owner);
return PartitionTaskStatus::Finished;
}
// Task is abandoned, initialize DROP PARTITION
LOG_DEBUG(log, "Task " << current_task_status_path << " has not been successfully finished by " << status.owner << ". Partition will be dropped and refilled.");
create_is_dirty_node(clean_state_clock);
return PartitionTaskStatus::Error;
}
}
/// Check that destination partition is empty if we are first worker
/// NOTE: this check is incorrect if pull and push tables have different partition key!
String clean_start_status;
if (!zookeeper->tryGet(task_partition.getPartitionCleanStartPath(), clean_start_status) || clean_start_status != "ok")
{
zookeeper->createIfNotExists(task_partition.getPartitionCleanStartPath(), "");
auto checker = zkutil::EphemeralNodeHolder::create(task_partition.getPartitionCleanStartPath() + "/checker", *zookeeper, host_id);
// Maybe we are the first worker
ASTPtr query_select_ast = get_select_query(task_shard.table_split_shard, "count()");
UInt64 count;
{
Context local_context = context;
// Use pull (i.e. readonly) settings, but fetch data from destination servers
local_context.getSettingsRef() = task_cluster->settings_pull;
local_context.getSettingsRef().skip_unavailable_shards = true;
Block block = getBlockWithAllStreamData(InterpreterFactory::get(query_select_ast, local_context)->execute().in);
count = (block) ? block.safeGetByPosition(0).column->getUInt(0) : 0;
}
if (count != 0)
{
Coordination::Stat stat_shards;
zookeeper->get(task_partition.getPartitionShardsPath(), &stat_shards);
/// NOTE: partition is still fresh if dirt discovery happens before cleaning
if (stat_shards.numChildren == 0)
{
LOG_WARNING(log, "There are no workers for partition " << task_partition.name
<< ", but destination table contains " << count << " rows"
<< ". Partition will be dropped and refilled.");
create_is_dirty_node(clean_state_clock);
return PartitionTaskStatus::Error;
}
}
zookeeper->set(task_partition.getPartitionCleanStartPath(), "ok");
}
/// At this point, we need to sync that the destination table is clean
/// before any actual work
/// Try start processing, create node about it
{
String start_state = TaskStateWithOwner::getData(TaskState::Started, host_id);
CleanStateClock new_clean_state_clock (zookeeper, is_dirty_flag_path, is_dirt_cleaned_path);
if (clean_state_clock != new_clean_state_clock)
{
LOG_INFO(log, "Partition " << task_partition.name << " clean state changed, cowardly bailing");
return PartitionTaskStatus::Error;
}
else if (!new_clean_state_clock.is_clean())
{
LOG_INFO(log, "Partition " << task_partition.name << " is dirty and will be dropped and refilled");
create_is_dirty_node(new_clean_state_clock);
return PartitionTaskStatus::Error;
}
zookeeper->create(current_task_status_path, start_state, zkutil::CreateMode::Persistent);
}
/// Try create table (if not exists) on each shard
{
auto create_query_push_ast = rewriteCreateQueryStorage(task_shard.current_pull_table_create_query, task_table.table_push, task_table.engine_push_ast);
create_query_push_ast->as<ASTCreateQuery &>().if_not_exists = true;
String query = queryToString(create_query_push_ast);
LOG_DEBUG(log, "Create destination tables. Query: " << query);
UInt64 shards = executeQueryOnCluster(task_table.cluster_push, query, create_query_push_ast, &task_cluster->settings_push,
PoolMode::GET_MANY);
LOG_DEBUG(log, "Destination tables " << getQuotedTable(task_table.table_push) << " have been created on " << shards
<< " shards of " << task_table.cluster_push->getShardCount());
}
/// Do the copying
{
bool inject_fault = false;
if (copy_fault_probability > 0)
{
double value = std::uniform_real_distribution<>(0, 1)(task_table.task_cluster.random_engine);
inject_fault = value < copy_fault_probability;
}
// Select all fields
ASTPtr query_select_ast = get_select_query(task_shard.table_read_shard, "*", inject_fault ? "1" : "");
LOG_DEBUG(log, "Executing SELECT query and pull from " << task_shard.getDescription()
<< " : " << queryToString(query_select_ast));
ASTPtr query_insert_ast;
{
String query;
query += "INSERT INTO " + getQuotedTable(task_shard.table_split_shard) + " VALUES ";
ParserQuery p_query(query.data() + query.size());
query_insert_ast = parseQuery(p_query, query, 0);
LOG_DEBUG(log, "Executing INSERT query: " << query);
}
try
{
/// Custom INSERT SELECT implementation
Context context_select = context;
context_select.getSettingsRef() = task_cluster->settings_pull;
Context context_insert = context;
context_insert.getSettingsRef() = task_cluster->settings_push;
BlockInputStreamPtr input;
BlockOutputStreamPtr output;
{
BlockIO io_select = InterpreterFactory::get(query_select_ast, context_select)->execute();
BlockIO io_insert = InterpreterFactory::get(query_insert_ast, context_insert)->execute();
input = io_select.in;
output = io_insert.out;
}
/// Fail-fast optimization to abort copying when the current clean state expires
std::future<Coordination::ExistsResponse> future_is_dirty_checker;
Stopwatch watch(CLOCK_MONOTONIC_COARSE);
constexpr UInt64 check_period_milliseconds = 500;
/// Will asynchronously check that ZooKeeper connection and is_dirty flag appearing while copying data
auto cancel_check = [&] ()
{
if (zookeeper->expired())
throw Exception("ZooKeeper session is expired, cancel INSERT SELECT", ErrorCodes::UNFINISHED);
if (!future_is_dirty_checker.valid())
future_is_dirty_checker = zookeeper->asyncExists(is_dirty_flag_path);
/// check_period_milliseconds should less than average insert time of single block
/// Otherwise, the insertion will slow a little bit
if (watch.elapsedMilliseconds() >= check_period_milliseconds)
{
Coordination::ExistsResponse status = future_is_dirty_checker.get();
if (status.error != Coordination::ZNONODE)
{
LogicalClock dirt_discovery_epoch (status.stat.mzxid);
if (dirt_discovery_epoch == clean_state_clock.discovery_zxid)
return false;
throw Exception("Partition is dirty, cancel INSERT SELECT", ErrorCodes::UNFINISHED);
}
}
return false;
};
/// Update statistics
/// It is quite rough: bytes_copied don't take into account DROP PARTITION.
auto update_stats = [&cluster_partition] (const Block & block)
{
cluster_partition.bytes_copied += block.bytes();
cluster_partition.rows_copied += block.rows();
cluster_partition.blocks_copied += 1;
};
/// Main work is here
copyData(*input, *output, cancel_check, update_stats);
// Just in case
if (future_is_dirty_checker.valid())
future_is_dirty_checker.get();
if (inject_fault)
throw Exception("Copy fault injection is activated", ErrorCodes::UNFINISHED);
}
catch (...)
{
tryLogCurrentException(log, "An error occurred during copying, partition will be marked as dirty");
return PartitionTaskStatus::Error;
}
}
/// Finalize the processing, change state of current partition task (and also check is_dirty flag)
{
String state_finished = TaskStateWithOwner::getData(TaskState::Finished, host_id);
CleanStateClock new_clean_state_clock (zookeeper, is_dirty_flag_path, is_dirt_cleaned_path);
if (clean_state_clock != new_clean_state_clock)
{
LOG_INFO(log, "Partition " << task_partition.name << " clean state changed, cowardly bailing");
return PartitionTaskStatus::Error;
}
else if (!new_clean_state_clock.is_clean())
{
LOG_INFO(log, "Partition " << task_partition.name << " became dirty and will be dropped and refilled");
create_is_dirty_node(new_clean_state_clock);
return PartitionTaskStatus::Error;
}
zookeeper->set(current_task_status_path, state_finished, 0);
}
LOG_INFO(log, "Partition " << task_partition.name << " copied");
return PartitionTaskStatus::Finished;
}
void ClusterCopier::dropAndCreateLocalTable(const ASTPtr & create_ast)
{
const auto & create = create_ast->as<ASTCreateQuery &>();
dropLocalTableIfExists({create.database, create.table});
InterpreterCreateQuery interpreter(create_ast, context);
interpreter.execute();
}
void ClusterCopier::dropLocalTableIfExists(const DatabaseAndTableName & table_name) const
{
auto drop_ast = std::make_shared<ASTDropQuery>();
drop_ast->if_exists = true;
drop_ast->database = table_name.first;
drop_ast->table = table_name.second;
InterpreterDropQuery interpreter(drop_ast, context);
interpreter.execute();
}
String ClusterCopier::getRemoteCreateTable(const DatabaseAndTableName & table, Connection & connection, const Settings * settings)
{
String query = "SHOW CREATE TABLE " + getQuotedTable(table);
Block block = getBlockWithAllStreamData(std::make_shared<RemoteBlockInputStream>(
connection, query, InterpreterShowCreateQuery::getSampleBlock(), context, settings));
return typeid_cast<const ColumnString &>(*block.safeGetByPosition(0).column).getDataAt(0).toString();
}
ASTPtr ClusterCopier::getCreateTableForPullShard(const ConnectionTimeouts & timeouts, TaskShard & task_shard)
{
/// Fetch and parse (possibly) new definition
auto connection_entry = task_shard.info.pool->get(timeouts, &task_cluster->settings_pull);
String create_query_pull_str = getRemoteCreateTable(
task_shard.task_table.table_pull,
*connection_entry,
&task_cluster->settings_pull);
ParserCreateQuery parser_create_query;
return parseQuery(parser_create_query, create_query_pull_str, 0);
}
void ClusterCopier::createShardInternalTables(const ConnectionTimeouts & timeouts, TaskShard & task_shard, bool create_split)
{
TaskTable & task_table = task_shard.task_table;
/// We need to update table definitions for each part, it could be changed after ALTER
task_shard.current_pull_table_create_query = getCreateTableForPullShard(timeouts, task_shard);
/// Create local Distributed tables:
/// a table fetching data from current shard and a table inserting data to the whole destination cluster
String read_shard_prefix = ".read_shard_" + toString(task_shard.indexInCluster()) + ".";
String split_shard_prefix = ".split.";
task_shard.table_read_shard = DatabaseAndTableName(working_database_name, read_shard_prefix + task_table.table_id);
task_shard.table_split_shard = DatabaseAndTableName(working_database_name, split_shard_prefix + task_table.table_id);
/// Create special cluster with single shard
String shard_read_cluster_name = read_shard_prefix + task_table.cluster_pull_name;
ClusterPtr cluster_pull_current_shard = task_table.cluster_pull->getClusterWithSingleShard(task_shard.indexInCluster());
context.setCluster(shard_read_cluster_name, cluster_pull_current_shard);
auto storage_shard_ast = createASTStorageDistributed(shard_read_cluster_name, task_table.table_pull.first, task_table.table_pull.second);
const auto & storage_split_ast = task_table.engine_split_ast;
auto create_query_ast = removeAliasColumnsFromCreateQuery(task_shard.current_pull_table_create_query);
auto create_table_pull_ast = rewriteCreateQueryStorage(create_query_ast, task_shard.table_read_shard, storage_shard_ast);
auto create_table_split_ast = rewriteCreateQueryStorage(create_query_ast, task_shard.table_split_shard, storage_split_ast);
dropAndCreateLocalTable(create_table_pull_ast);
if (create_split)
dropAndCreateLocalTable(create_table_split_ast);
}
std::set<String> ClusterCopier::getShardPartitions(const ConnectionTimeouts & timeouts, TaskShard & task_shard)
{
createShardInternalTables(timeouts, task_shard, false);
TaskTable & task_table = task_shard.task_table;
String query;
{
WriteBufferFromOwnString wb;
wb << "SELECT DISTINCT " << queryToString(task_table.engine_push_partition_key_ast) << " AS partition FROM"
<< " " << getQuotedTable(task_shard.table_read_shard) << " ORDER BY partition DESC";
query = wb.str();
}
ParserQuery parser_query(query.data() + query.size());
ASTPtr query_ast = parseQuery(parser_query, query, 0);
LOG_DEBUG(log, "Computing destination partition set, executing query: " << query);
Context local_context = context;
local_context.setSettings(task_cluster->settings_pull);
Block block = getBlockWithAllStreamData(InterpreterFactory::get(query_ast, local_context)->execute().in);
std::set<String> res;
if (block)
{
ColumnWithTypeAndName & column = block.getByPosition(0);
task_shard.partition_key_column = column;
for (size_t i = 0; i < column.column->size(); ++i)
{
WriteBufferFromOwnString wb;
column.type->serializeAsTextQuoted(*column.column, i, wb, FormatSettings());
res.emplace(wb.str());
}
}
LOG_DEBUG(log, "There are " << res.size() << " destination partitions in shard " << task_shard.getDescription());
return res;
}
bool ClusterCopier::checkShardHasPartition(const ConnectionTimeouts & timeouts, TaskShard & task_shard, const String & partition_quoted_name)
{
createShardInternalTables(timeouts, task_shard, false);
TaskTable & task_table = task_shard.task_table;
std::string query = "SELECT 1 FROM " + getQuotedTable(task_shard.table_read_shard)
+ " WHERE (" + queryToString(task_table.engine_push_partition_key_ast) + " = (" + partition_quoted_name + " AS partition_key))";
if (!task_table.where_condition_str.empty())
query += " AND (" + task_table.where_condition_str + ")";
query += " LIMIT 1";
LOG_DEBUG(log, "Checking shard " << task_shard.getDescription() << " for partition "
<< partition_quoted_name << " existence, executing query: " << query);
ParserQuery parser_query(query.data() + query.size());
ASTPtr query_ast = parseQuery(parser_query, query, 0);
Context local_context = context;
local_context.setSettings(task_cluster->settings_pull);
return InterpreterFactory::get(query_ast, local_context)->execute().in->read().rows() != 0;
}
UInt64 ClusterCopier::executeQueryOnCluster(
const ClusterPtr & cluster,
const String & query,
const ASTPtr & query_ast_,
const Settings * settings,
PoolMode pool_mode,
UInt64 max_successful_executions_per_shard) const
{
auto num_shards = cluster->getShardsInfo().size();
std::vector<UInt64> per_shard_num_successful_replicas(num_shards, 0);
ASTPtr query_ast;
if (query_ast_ == nullptr)
{
ParserQuery p_query(query.data() + query.size());
query_ast = parseQuery(p_query, query, 0);
}
else
query_ast = query_ast_;
/// We need to execute query on one replica at least
auto do_for_shard = [&] (UInt64 shard_index)
{
const Cluster::ShardInfo & shard = cluster->getShardsInfo().at(shard_index);
UInt64 & num_successful_executions = per_shard_num_successful_replicas.at(shard_index);
num_successful_executions = 0;
auto increment_and_check_exit = [&] ()
{
++num_successful_executions;
return max_successful_executions_per_shard && num_successful_executions >= max_successful_executions_per_shard;
};
UInt64 num_replicas = cluster->getShardsAddresses().at(shard_index).size();
UInt64 num_local_replicas = shard.getLocalNodeCount();
UInt64 num_remote_replicas = num_replicas - num_local_replicas;
/// In that case we don't have local replicas, but do it just in case
for (UInt64 i = 0; i < num_local_replicas; ++i)
{
auto interpreter = InterpreterFactory::get(query_ast, context);
interpreter->execute();
if (increment_and_check_exit())
return;
}
/// Will try to make as many as possible queries
if (shard.hasRemoteConnections())
{
Settings current_settings = settings ? *settings : task_cluster->settings_common;
current_settings.max_parallel_replicas = num_remote_replicas ? num_remote_replicas : 1;
auto timeouts = ConnectionTimeouts::getTCPTimeoutsWithFailover(current_settings).getSaturated(current_settings.max_execution_time);
auto connections = shard.pool->getMany(timeouts, &current_settings, pool_mode);
for (auto & connection : connections)
{
if (connection.isNull())
continue;
try
{
/// CREATE TABLE and DROP PARTITION queries return empty block
RemoteBlockInputStream stream{*connection, query, Block{}, context, &current_settings};
NullBlockOutputStream output{Block{}};
copyData(stream, output);
if (increment_and_check_exit())
return;
}
catch (const Exception &)
{
LOG_INFO(log, getCurrentExceptionMessage(false, true));
}
}
}
};
{
ThreadPool thread_pool(std::min<UInt64>(num_shards, getNumberOfPhysicalCPUCores()));
for (UInt64 shard_index = 0; shard_index < num_shards; ++shard_index)
thread_pool.scheduleOrThrowOnError([=] { do_for_shard(shard_index); });
thread_pool.wait();
}
UInt64 successful_shards = 0;
for (UInt64 num_replicas : per_shard_num_successful_replicas)
successful_shards += (num_replicas > 0);
return successful_shards;
}
}