ClickHouse/src/Storages/StorageDistributed.cpp
Maksim Kita e361f5943f
Merge pull request #22999 from azat/no-optimize_skip_unused_shards-single-node
Do not perform optimize_skip_unused_shards for cluster with one node
2021-04-15 14:36:56 +03:00

1271 lines
47 KiB
C++

#include <Storages/StorageDistributed.h>
#include <Databases/IDatabase.h>
#include <Disks/IDisk.h>
#include <DataStreams/RemoteBlockInputStream.h>
#include <DataTypes/DataTypeFactory.h>
#include <DataTypes/DataTypeUUID.h>
#include <DataTypes/DataTypesNumber.h>
#include <Storages/Distributed/DistributedBlockOutputStream.h>
#include <Storages/StorageFactory.h>
#include <Storages/AlterCommands.h>
#include <Columns/ColumnConst.h>
#include <Common/Macros.h>
#include <Common/ProfileEvents.h>
#include <Common/escapeForFileName.h>
#include <Common/typeid_cast.h>
#include <Common/quoteString.h>
#include <Common/randomSeed.h>
#include <Common/formatReadable.h>
#include <Parsers/ASTDropQuery.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTInsertQuery.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Parsers/ParserAlterQuery.h>
#include <Parsers/TablePropertiesQueriesASTs.h>
#include <Parsers/parseQuery.h>
#include <Parsers/queryToString.h>
#include <Interpreters/ClusterProxy/SelectStreamFactory.h>
#include <Interpreters/ClusterProxy/executeQuery.h>
#include <Interpreters/Cluster.h>
#include <Interpreters/ExpressionAnalyzer.h>
#include <Interpreters/InterpreterAlterQuery.h>
#include <Interpreters/InterpreterDescribeQuery.h>
#include <Interpreters/InterpreterSelectQuery.h>
#include <Interpreters/JoinedTables.h>
#include <Interpreters/TranslateQualifiedNamesVisitor.h>
#include <Interpreters/TreeRewriter.h>
#include <Interpreters/Context.h>
#include <Interpreters/createBlockSelector.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Interpreters/getClusterName.h>
#include <Interpreters/getTableExpressions.h>
#include <Functions/IFunction.h>
#include <Processors/QueryPlan/BuildQueryPipelineSettings.h>
#include <Processors/QueryPlan/Optimizations/QueryPlanOptimizationSettings.h>
#include <Processors/QueryPlan/ReadFromPreparedSource.h>
#include <Processors/Sources/NullSource.h>
#include <Processors/Sources/SourceFromInputStream.h>
#include <Processors/NullSink.h>
#include <Core/Field.h>
#include <Core/Settings.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromString.h>
#include <IO/Operators.h>
#include <IO/ConnectionTimeoutsContext.h>
#include <Poco/DirectoryIterator.h>
#include <memory>
#include <filesystem>
#include <optional>
#include <cassert>
namespace
{
const UInt64 FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_HAS_SHARDING_KEY = 1;
const UInt64 FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_ALWAYS = 2;
const UInt64 DISTRIBUTED_GROUP_BY_NO_MERGE_AFTER_AGGREGATION = 2;
const UInt64 PARALLEL_DISTRIBUTED_INSERT_SELECT_ALL = 2;
}
namespace ProfileEvents
{
extern const Event DistributedRejectedInserts;
extern const Event DistributedDelayedInserts;
extern const Event DistributedDelayedInsertsMilliseconds;
}
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int NOT_IMPLEMENTED;
extern const int STORAGE_REQUIRES_PARAMETER;
extern const int BAD_ARGUMENTS;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int INCORRECT_NUMBER_OF_COLUMNS;
extern const int INFINITE_LOOP;
extern const int TYPE_MISMATCH;
extern const int TOO_MANY_ROWS;
extern const int UNABLE_TO_SKIP_UNUSED_SHARDS;
extern const int INVALID_SHARD_ID;
extern const int ALTER_OF_COLUMN_IS_FORBIDDEN;
extern const int DISTRIBUTED_TOO_MANY_PENDING_BYTES;
extern const int ARGUMENT_OUT_OF_BOUND;
}
namespace ActionLocks
{
extern const StorageActionBlockType DistributedSend;
}
namespace
{
/// select query has database, table and table function names as AST pointers
/// Creates a copy of query, changes database, table and table function names.
ASTPtr rewriteSelectQuery(const ASTPtr & query, const std::string & database, const std::string & table, ASTPtr table_function_ptr = nullptr)
{
auto modified_query_ast = query->clone();
ASTSelectQuery & select_query = modified_query_ast->as<ASTSelectQuery &>();
// Get rid of the settings clause so we don't send them to remote. Thus newly non-important
// settings won't break any remote parser. It's also more reasonable since the query settings
// are written into the query context and will be sent by the query pipeline.
select_query.setExpression(ASTSelectQuery::Expression::SETTINGS, {});
if (table_function_ptr)
select_query.addTableFunction(table_function_ptr);
else
select_query.replaceDatabaseAndTable(database, table);
/// Restore long column names (cause our short names are ambiguous).
/// TODO: aliased table functions & CREATE TABLE AS table function cases
if (!table_function_ptr)
{
RestoreQualifiedNamesVisitor::Data data;
data.distributed_table = DatabaseAndTableWithAlias(*getTableExpression(query->as<ASTSelectQuery &>(), 0));
data.remote_table.database = database;
data.remote_table.table = table;
data.rename = true;
RestoreQualifiedNamesVisitor(data).visit(modified_query_ast);
}
return modified_query_ast;
}
/// The columns list in the original INSERT query is incorrect because inserted blocks are transformed
/// to the form of the sample block of the Distributed table. So we rewrite it and add all columns from
/// the sample block instead.
ASTPtr createInsertToRemoteTableQuery(const std::string & database, const std::string & table, const Block & sample_block_non_materialized)
{
auto query = std::make_shared<ASTInsertQuery>();
query->table_id = StorageID(database, table);
auto columns = std::make_shared<ASTExpressionList>();
query->columns = columns;
query->children.push_back(columns);
for (const auto & col : sample_block_non_materialized)
columns->children.push_back(std::make_shared<ASTIdentifier>(col.name));
return query;
}
/// Calculate maximum number in file names in directory and all subdirectories.
/// To ensure global order of data blocks yet to be sent across server restarts.
UInt64 getMaximumFileNumber(const std::string & dir_path)
{
UInt64 res = 0;
std::filesystem::recursive_directory_iterator begin(dir_path);
std::filesystem::recursive_directory_iterator end;
for (auto it = begin; it != end; ++it)
{
const auto & file_path = it->path();
if (!std::filesystem::is_regular_file(*it) || !endsWith(file_path.filename().string(), ".bin"))
continue;
UInt64 num = 0;
try
{
num = parse<UInt64>(file_path.filename().stem().string());
}
catch (Exception & e)
{
e.addMessage("Unexpected file name " + file_path.filename().string() + " found at " + file_path.parent_path().string() + ", should have numeric base name.");
throw;
}
if (num > res)
res = num;
}
return res;
}
std::string makeFormattedListOfShards(const ClusterPtr & cluster)
{
WriteBufferFromOwnString buf;
bool head = true;
buf << "[";
for (const auto & shard_info : cluster->getShardsInfo())
{
(head ? buf : buf << ", ") << shard_info.shard_num;
head = false;
}
buf << "]";
return buf.str();
}
ExpressionActionsPtr buildShardingKeyExpression(const ASTPtr & sharding_key, ContextPtr context, const NamesAndTypesList & columns, bool project)
{
ASTPtr query = sharding_key;
auto syntax_result = TreeRewriter(context).analyze(query, columns);
return ExpressionAnalyzer(query, syntax_result, context).getActions(project);
}
bool isExpressionActionsDeterministics(const ExpressionActionsPtr & actions)
{
for (const auto & action : actions->getActions())
{
if (action.node->type != ActionsDAG::ActionType::FUNCTION)
continue;
if (!action.node->function_base->isDeterministic())
return false;
}
return true;
}
class ReplacingConstantExpressionsMatcher
{
public:
using Data = Block;
static bool needChildVisit(ASTPtr &, const ASTPtr &)
{
return true;
}
static void visit(ASTPtr & node, Block & block_with_constants)
{
if (!node->as<ASTFunction>())
return;
std::string name = node->getColumnName();
if (block_with_constants.has(name))
{
auto result = block_with_constants.getByName(name);
if (!isColumnConst(*result.column))
return;
node = std::make_shared<ASTLiteral>(assert_cast<const ColumnConst &>(*result.column).getField());
}
}
};
void replaceConstantExpressions(
ASTPtr & node,
ContextPtr context,
const NamesAndTypesList & columns,
ConstStoragePtr storage,
const StorageMetadataPtr & metadata_snapshot)
{
auto syntax_result = TreeRewriter(context).analyze(node, columns, storage, metadata_snapshot);
Block block_with_constants = KeyCondition::getBlockWithConstants(node, syntax_result, context);
InDepthNodeVisitor<ReplacingConstantExpressionsMatcher, true> visitor(block_with_constants);
visitor.visit(node);
}
/// Returns one of the following:
/// - QueryProcessingStage::Complete
/// - QueryProcessingStage::WithMergeableStateAfterAggregation
/// - none (in this case regular WithMergeableState should be used)
std::optional<QueryProcessingStage::Enum> getOptimizedQueryProcessingStage(const ASTPtr & query_ptr, bool extremes, const Block & sharding_key_block)
{
const auto & select = query_ptr->as<ASTSelectQuery &>();
auto sharding_block_has = [&](const auto & exprs, size_t limit = SIZE_MAX) -> bool
{
size_t i = 0;
for (auto & expr : exprs)
{
++i;
if (i > limit)
break;
auto id = expr->template as<ASTIdentifier>();
if (!id)
return false;
/// TODO: if GROUP BY contains multiIf()/if() it should contain only columns from sharding_key
if (!sharding_key_block.has(id->name()))
return false;
}
return true;
};
// GROUP BY qualifiers
// - TODO: WITH TOTALS can be implemented
// - TODO: WITH ROLLUP can be implemented (I guess)
if (select.group_by_with_totals || select.group_by_with_rollup || select.group_by_with_cube)
return {};
// TODO: extremes support can be implemented
if (extremes)
return {};
// DISTINCT
if (select.distinct)
{
if (!sharding_block_has(select.select()->children))
return {};
}
// GROUP BY
const ASTPtr group_by = select.groupBy();
if (!group_by)
{
if (!select.distinct)
return {};
}
else
{
if (!sharding_block_has(group_by->children, 1))
return {};
}
// ORDER BY
const ASTPtr order_by = select.orderBy();
if (order_by)
return QueryProcessingStage::WithMergeableStateAfterAggregation;
// LIMIT BY
// LIMIT
// OFFSET
if (select.limitBy() || select.limitLength() || select.limitOffset())
return QueryProcessingStage::WithMergeableStateAfterAggregation;
// Only simple SELECT FROM GROUP BY sharding_key can use Complete state.
return QueryProcessingStage::Complete;
}
size_t getClusterQueriedNodes(const Settings & settings, const ClusterPtr & cluster)
{
size_t num_local_shards = cluster->getLocalShardCount();
size_t num_remote_shards = cluster->getRemoteShardCount();
return (num_remote_shards * settings.max_parallel_replicas) + num_local_shards;
}
}
/// For destruction of std::unique_ptr of type that is incomplete in class definition.
StorageDistributed::~StorageDistributed() = default;
NamesAndTypesList StorageDistributed::getVirtuals() const
{
/// NOTE This is weird. Most of these virtual columns are part of MergeTree
/// tables info. But Distributed is general-purpose engine.
return NamesAndTypesList{
NameAndTypePair("_table", std::make_shared<DataTypeString>()),
NameAndTypePair("_part", std::make_shared<DataTypeString>()),
NameAndTypePair("_part_index", std::make_shared<DataTypeUInt64>()),
NameAndTypePair("_part_uuid", std::make_shared<DataTypeUUID>()),
NameAndTypePair("_partition_id", std::make_shared<DataTypeString>()),
NameAndTypePair("_sample_factor", std::make_shared<DataTypeFloat64>()),
NameAndTypePair("_shard_num", std::make_shared<DataTypeUInt32>()),
};
}
StorageDistributed::StorageDistributed(
const StorageID & id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
const String & remote_database_,
const String & remote_table_,
const String & cluster_name_,
ContextPtr context_,
const ASTPtr & sharding_key_,
const String & storage_policy_name_,
const String & relative_data_path_,
const DistributedSettings & distributed_settings_,
bool attach_,
ClusterPtr owned_cluster_)
: IStorage(id_)
, WithContext(context_->getGlobalContext())
, remote_database(remote_database_)
, remote_table(remote_table_)
, log(&Poco::Logger::get("StorageDistributed (" + id_.table_name + ")"))
, owned_cluster(std::move(owned_cluster_))
, cluster_name(getContext()->getMacros()->expand(cluster_name_))
, has_sharding_key(sharding_key_)
, relative_data_path(relative_data_path_)
, distributed_settings(distributed_settings_)
, rng(randomSeed())
{
StorageInMemoryMetadata storage_metadata;
storage_metadata.setColumns(columns_);
storage_metadata.setConstraints(constraints_);
setInMemoryMetadata(storage_metadata);
if (sharding_key_)
{
sharding_key_expr = buildShardingKeyExpression(sharding_key_, getContext(), storage_metadata.getColumns().getAllPhysical(), false);
sharding_key_column_name = sharding_key_->getColumnName();
sharding_key_is_deterministic = isExpressionActionsDeterministics(sharding_key_expr);
}
if (!relative_data_path.empty())
{
storage_policy = getContext()->getStoragePolicy(storage_policy_name_);
data_volume = storage_policy->getVolume(0);
if (storage_policy->getVolumes().size() > 1)
LOG_WARNING(log, "Storage policy for Distributed table has multiple volumes. "
"Only {} volume will be used to store data. Other will be ignored.", data_volume->getName());
}
/// Sanity check. Skip check if the table is already created to allow the server to start.
if (!attach_ && !cluster_name.empty())
{
size_t num_local_shards = getContext()->getCluster(cluster_name)->getLocalShardCount();
if (num_local_shards && remote_database == id_.database_name && remote_table == id_.table_name)
throw Exception("Distributed table " + id_.table_name + " looks at itself", ErrorCodes::INFINITE_LOOP);
}
}
StorageDistributed::StorageDistributed(
const StorageID & id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
ASTPtr remote_table_function_ptr_,
const String & cluster_name_,
ContextPtr context_,
const ASTPtr & sharding_key_,
const String & storage_policy_name_,
const String & relative_data_path_,
const DistributedSettings & distributed_settings_,
bool attach,
ClusterPtr owned_cluster_)
: StorageDistributed(id_, columns_, constraints_, String{}, String{}, cluster_name_, context_, sharding_key_,
storage_policy_name_, relative_data_path_, distributed_settings_, attach, std::move(owned_cluster_))
{
remote_table_function_ptr = std::move(remote_table_function_ptr_);
}
QueryProcessingStage::Enum StorageDistributed::getQueryProcessingStage(
ContextPtr local_context, QueryProcessingStage::Enum to_stage, SelectQueryInfo & query_info) const
{
const auto & settings = local_context->getSettingsRef();
auto metadata_snapshot = getInMemoryMetadataPtr();
ClusterPtr cluster = getCluster();
query_info.cluster = cluster;
/// Always calculate optimized cluster here, to avoid conditions during read()
/// (Anyway it will be calculated in the read())
if (getClusterQueriedNodes(settings, cluster) > 1 && settings.optimize_skip_unused_shards)
{
ClusterPtr optimized_cluster = getOptimizedCluster(local_context, metadata_snapshot, query_info.query);
if (optimized_cluster)
{
LOG_DEBUG(log, "Skipping irrelevant shards - the query will be sent to the following shards of the cluster (shard numbers): {}",
makeFormattedListOfShards(optimized_cluster));
cluster = optimized_cluster;
query_info.optimized_cluster = cluster;
}
else
{
LOG_DEBUG(log, "Unable to figure out irrelevant shards from WHERE/PREWHERE clauses - the query will be sent to all shards of the cluster{}",
has_sharding_key ? "" : " (no sharding key)");
}
}
if (settings.distributed_group_by_no_merge)
{
if (settings.distributed_group_by_no_merge == DISTRIBUTED_GROUP_BY_NO_MERGE_AFTER_AGGREGATION)
return QueryProcessingStage::WithMergeableStateAfterAggregation;
else
return QueryProcessingStage::Complete;
}
/// Nested distributed query cannot return Complete stage,
/// since the parent query need to aggregate the results after.
if (to_stage == QueryProcessingStage::WithMergeableState)
return QueryProcessingStage::WithMergeableState;
/// If there is only one node, the query can be fully processed by the
/// shard, initiator will work as a proxy only.
if (getClusterQueriedNodes(settings, cluster) == 1)
return QueryProcessingStage::Complete;
if (settings.optimize_skip_unused_shards &&
settings.optimize_distributed_group_by_sharding_key &&
has_sharding_key &&
(settings.allow_nondeterministic_optimize_skip_unused_shards || sharding_key_is_deterministic))
{
Block sharding_key_block = sharding_key_expr->getSampleBlock();
auto stage = getOptimizedQueryProcessingStage(query_info.query, settings.extremes, sharding_key_block);
if (stage)
{
LOG_DEBUG(log, "Force processing stage to {}", QueryProcessingStage::toString(*stage));
return *stage;
}
}
return QueryProcessingStage::WithMergeableState;
}
Pipe StorageDistributed::read(
const Names & column_names,
const StorageMetadataPtr & metadata_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
const size_t max_block_size,
const unsigned num_streams)
{
QueryPlan plan;
read(plan, column_names, metadata_snapshot, query_info, local_context, processed_stage, max_block_size, num_streams);
return plan.convertToPipe(
QueryPlanOptimizationSettings::fromContext(local_context),
BuildQueryPipelineSettings::fromContext(local_context));
}
void StorageDistributed::read(
QueryPlan & query_plan,
const Names & column_names,
const StorageMetadataPtr & metadata_snapshot,
SelectQueryInfo & query_info,
ContextPtr local_context,
QueryProcessingStage::Enum processed_stage,
const size_t /*max_block_size*/,
const unsigned /*num_streams*/)
{
const auto & modified_query_ast = rewriteSelectQuery(
query_info.query, remote_database, remote_table, remote_table_function_ptr);
Block header =
InterpreterSelectQuery(query_info.query, local_context, SelectQueryOptions(processed_stage).analyze()).getSampleBlock();
/// Return directly (with correct header) if no shard to query.
if (query_info.getCluster()->getShardsInfo().empty())
{
Pipe pipe(std::make_shared<NullSource>(header));
auto read_from_pipe = std::make_unique<ReadFromPreparedSource>(std::move(pipe));
read_from_pipe->setStepDescription("Read from NullSource (Distributed)");
query_plan.addStep(std::move(read_from_pipe));
return;
}
const Scalars & scalars = local_context->hasQueryContext() ? local_context->getQueryContext()->getScalars() : Scalars{};
bool has_virtual_shard_num_column = std::find(column_names.begin(), column_names.end(), "_shard_num") != column_names.end();
if (has_virtual_shard_num_column && !isVirtualColumn("_shard_num", metadata_snapshot))
has_virtual_shard_num_column = false;
ClusterProxy::SelectStreamFactory select_stream_factory = remote_table_function_ptr
? ClusterProxy::SelectStreamFactory(
header, processed_stage, remote_table_function_ptr, scalars, has_virtual_shard_num_column, local_context->getExternalTables())
: ClusterProxy::SelectStreamFactory(
header,
processed_stage,
StorageID{remote_database, remote_table},
scalars,
has_virtual_shard_num_column,
local_context->getExternalTables());
ClusterProxy::executeQuery(query_plan, select_stream_factory, log,
modified_query_ast, local_context, query_info,
sharding_key_expr, sharding_key_column_name,
getCluster());
/// This is a bug, it is possible only when there is no shards to query, and this is handled earlier.
if (!query_plan.isInitialized())
throw Exception("Pipeline is not initialized", ErrorCodes::LOGICAL_ERROR);
}
BlockOutputStreamPtr StorageDistributed::write(const ASTPtr &, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context)
{
auto cluster = getCluster();
const auto & settings = local_context->getSettingsRef();
/// Ban an attempt to make async insert into the table belonging to DatabaseMemory
if (!storage_policy && !owned_cluster && !settings.insert_distributed_sync && !settings.insert_shard_id)
{
throw Exception("Storage " + getName() + " must have own data directory to enable asynchronous inserts",
ErrorCodes::BAD_ARGUMENTS);
}
auto shard_num = cluster->getLocalShardCount() + cluster->getRemoteShardCount();
/// If sharding key is not specified, then you can only write to a shard containing only one shard
if (!settings.insert_shard_id && !settings.insert_distributed_one_random_shard && !has_sharding_key && shard_num >= 2)
{
throw Exception(
"Method write is not supported by storage " + getName() + " with more than one shard and no sharding key provided",
ErrorCodes::STORAGE_REQUIRES_PARAMETER);
}
if (settings.insert_shard_id && settings.insert_shard_id > shard_num)
{
throw Exception("Shard id should be range from 1 to shard number", ErrorCodes::INVALID_SHARD_ID);
}
/// Force sync insertion if it is remote() table function
bool insert_sync = settings.insert_distributed_sync || settings.insert_shard_id || owned_cluster;
auto timeout = settings.insert_distributed_timeout;
/// DistributedBlockOutputStream will not own cluster, but will own ConnectionPools of the cluster
return std::make_shared<DistributedBlockOutputStream>(
local_context, *this, metadata_snapshot,
createInsertToRemoteTableQuery(
remote_database, remote_table, metadata_snapshot->getSampleBlockNonMaterialized()),
cluster, insert_sync, timeout);
}
QueryPipelinePtr StorageDistributed::distributedWrite(const ASTInsertQuery & query, ContextPtr local_context)
{
const Settings & settings = local_context->getSettingsRef();
std::shared_ptr<StorageDistributed> storage_src;
auto & select = query.select->as<ASTSelectWithUnionQuery &>();
auto new_query = std::dynamic_pointer_cast<ASTInsertQuery>(query.clone());
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)
{
storage_src = std::dynamic_pointer_cast<StorageDistributed>(joined_tables.getLeftTableStorage());
if (storage_src)
{
const auto select_with_union_query = std::make_shared<ASTSelectWithUnionQuery>();
select_with_union_query->list_of_selects = std::make_shared<ASTExpressionList>();
auto new_select_query = std::dynamic_pointer_cast<ASTSelectQuery>(select_query->clone());
select_with_union_query->list_of_selects->children.push_back(new_select_query);
new_select_query->replaceDatabaseAndTable(storage_src->getRemoteDatabaseName(), storage_src->getRemoteTableName());
new_query->select = select_with_union_query;
}
}
}
}
if (!storage_src || storage_src->getClusterName() != getClusterName())
{
return nullptr;
}
if (settings.parallel_distributed_insert_select == PARALLEL_DISTRIBUTED_INSERT_SELECT_ALL)
{
new_query->table_id = StorageID(getRemoteDatabaseName(), getRemoteTableName());
}
const auto & cluster = getCluster();
const auto & shards_info = cluster->getShardsInfo();
std::vector<std::unique_ptr<QueryPipeline>> pipelines;
String new_query_str = queryToString(new_query);
for (size_t shard_index : ext::range(0, shards_info.size()))
{
const auto & shard_info = shards_info[shard_index];
if (shard_info.isLocal())
{
InterpreterInsertQuery interpreter(new_query, local_context);
pipelines.emplace_back(std::make_unique<QueryPipeline>(interpreter.execute().pipeline));
}
else
{
auto timeouts = ConnectionTimeouts::getTCPTimeoutsWithFailover(settings);
auto connections = shard_info.pool->getMany(timeouts, &settings, PoolMode::GET_ONE);
if (connections.empty() || connections.front().isNull())
throw Exception(
"Expected exactly one connection for shard " + toString(shard_info.shard_num), ErrorCodes::LOGICAL_ERROR);
/// INSERT SELECT query returns empty block
auto in_stream = std::make_shared<RemoteBlockInputStream>(std::move(connections), new_query_str, Block{}, local_context);
pipelines.emplace_back(std::make_unique<QueryPipeline>());
pipelines.back()->init(Pipe(std::make_shared<SourceFromInputStream>(std::move(in_stream))));
pipelines.back()->setSinks([](const Block & header, QueryPipeline::StreamType) -> ProcessorPtr
{
return std::make_shared<EmptySink>(header);
});
}
}
return std::make_unique<QueryPipeline>(QueryPipeline::unitePipelines(std::move(pipelines)));
}
void StorageDistributed::checkAlterIsPossible(const AlterCommands & commands, ContextPtr local_context) const
{
auto name_deps = getDependentViewsByColumn(local_context);
for (const auto & command : commands)
{
if (command.type != AlterCommand::Type::ADD_COLUMN
&& command.type != AlterCommand::Type::MODIFY_COLUMN
&& command.type != AlterCommand::Type::DROP_COLUMN
&& command.type != AlterCommand::Type::COMMENT_COLUMN
&& command.type != AlterCommand::Type::RENAME_COLUMN)
throw Exception("Alter of type '" + alterTypeToString(command.type) + "' is not supported by storage " + getName(),
ErrorCodes::NOT_IMPLEMENTED);
if (command.type == AlterCommand::DROP_COLUMN)
{
const auto & deps_mv = name_deps[command.column_name];
if (!deps_mv.empty())
{
throw Exception(
"Trying to ALTER DROP column " + backQuoteIfNeed(command.column_name) + " which is referenced by materialized view "
+ toString(deps_mv),
ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
}
}
}
}
void StorageDistributed::alter(const AlterCommands & params, ContextPtr local_context, TableLockHolder &)
{
auto table_id = getStorageID();
checkAlterIsPossible(params, local_context);
StorageInMemoryMetadata new_metadata = getInMemoryMetadata();
params.apply(new_metadata, local_context);
DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(local_context, table_id, new_metadata);
setInMemoryMetadata(new_metadata);
}
void StorageDistributed::startup()
{
if (remote_database.empty() && !remote_table_function_ptr && !getCluster()->maybeCrossReplication())
LOG_WARNING(log, "Name of remote database is empty. Default database will be used implicitly.");
if (!storage_policy)
return;
for (const DiskPtr & disk : data_volume->getDisks())
createDirectoryMonitors(disk);
for (const String & path : getDataPaths())
{
UInt64 inc = getMaximumFileNumber(path);
if (inc > file_names_increment.value)
file_names_increment.value.store(inc);
}
LOG_DEBUG(log, "Auto-increment is {}", file_names_increment.value);
}
void StorageDistributed::shutdown()
{
monitors_blocker.cancelForever();
std::lock_guard lock(cluster_nodes_mutex);
LOG_DEBUG(log, "Joining background threads for async INSERT");
cluster_nodes_data.clear();
LOG_DEBUG(log, "Background threads for async INSERT joined");
}
void StorageDistributed::drop()
{
// Some INSERT in-between shutdown() and drop() can call
// requireDirectoryMonitor() again, so call shutdown() to clear them, but
// when the drop() (this function) executed none of INSERT is allowed in
// parallel.
//
// And second time shutdown() should be fast, since none of
// DirectoryMonitor should do anything, because ActionBlocker is canceled
// (in shutdown()).
shutdown();
// Distributed table w/o sharding_key does not allows INSERTs
if (relative_data_path.empty())
return;
LOG_DEBUG(log, "Removing pending blocks for async INSERT from filesystem on DROP TABLE");
auto disks = data_volume->getDisks();
for (const auto & disk : disks)
disk->removeRecursive(relative_data_path);
LOG_DEBUG(log, "Removed");
}
Strings StorageDistributed::getDataPaths() const
{
Strings paths;
if (relative_data_path.empty())
return paths;
for (const DiskPtr & disk : data_volume->getDisks())
paths.push_back(disk->getPath() + relative_data_path);
return paths;
}
void StorageDistributed::truncate(const ASTPtr &, const StorageMetadataPtr &, ContextPtr, TableExclusiveLockHolder &)
{
std::lock_guard lock(cluster_nodes_mutex);
LOG_DEBUG(log, "Removing pending blocks for async INSERT from filesystem on TRUNCATE TABLE");
for (auto it = cluster_nodes_data.begin(); it != cluster_nodes_data.end();)
{
it->second.directory_monitor->shutdownAndDropAllData();
it = cluster_nodes_data.erase(it);
}
LOG_DEBUG(log, "Removed");
}
StoragePolicyPtr StorageDistributed::getStoragePolicy() const
{
return storage_policy;
}
void StorageDistributed::createDirectoryMonitors(const DiskPtr & disk)
{
const std::string path(disk->getPath() + relative_data_path);
Poco::File{path}.createDirectories();
std::filesystem::directory_iterator begin(path);
std::filesystem::directory_iterator end;
for (auto it = begin; it != end; ++it)
{
const auto & dir_path = it->path();
if (std::filesystem::is_directory(dir_path))
{
const auto & tmp_path = dir_path / "tmp";
/// "tmp" created by DistributedBlockOutputStream
if (std::filesystem::is_directory(tmp_path) && std::filesystem::is_empty(tmp_path))
std::filesystem::remove(tmp_path);
if (std::filesystem::is_empty(dir_path))
{
LOG_DEBUG(log, "Removing {} (used for async INSERT into Distributed)", dir_path.string());
/// Will be created by DistributedBlockOutputStream on demand.
std::filesystem::remove(dir_path);
}
else
{
requireDirectoryMonitor(disk, dir_path.filename().string());
}
}
}
}
StorageDistributedDirectoryMonitor& StorageDistributed::requireDirectoryMonitor(const DiskPtr & disk, const std::string & name)
{
const std::string & disk_path = disk->getPath();
const std::string key(disk_path + name);
std::lock_guard lock(cluster_nodes_mutex);
auto & node_data = cluster_nodes_data[key];
if (!node_data.directory_monitor)
{
node_data.connection_pool = StorageDistributedDirectoryMonitor::createPool(name, *this);
node_data.directory_monitor = std::make_unique<StorageDistributedDirectoryMonitor>(
*this, disk, relative_data_path + name,
node_data.connection_pool,
monitors_blocker,
getContext()->getDistributedSchedulePool());
}
return *node_data.directory_monitor;
}
std::vector<StorageDistributedDirectoryMonitor::Status> StorageDistributed::getDirectoryMonitorsStatuses() const
{
std::vector<StorageDistributedDirectoryMonitor::Status> statuses;
std::lock_guard lock(cluster_nodes_mutex);
statuses.reserve(cluster_nodes_data.size());
for (const auto & node : cluster_nodes_data)
statuses.push_back(node.second.directory_monitor->getStatus());
return statuses;
}
std::optional<UInt64> StorageDistributed::totalBytes(const Settings &) const
{
UInt64 total_bytes = 0;
for (const auto & status : getDirectoryMonitorsStatuses())
total_bytes += status.bytes_count;
return total_bytes;
}
size_t StorageDistributed::getShardCount() const
{
return getCluster()->getShardCount();
}
ClusterPtr StorageDistributed::getCluster() const
{
return owned_cluster ? owned_cluster : getContext()->getCluster(cluster_name);
}
ClusterPtr StorageDistributed::getOptimizedCluster(
ContextPtr local_context, const StorageMetadataPtr & metadata_snapshot, const ASTPtr & query_ptr) const
{
ClusterPtr cluster = getCluster();
const Settings & settings = local_context->getSettingsRef();
bool sharding_key_is_usable = settings.allow_nondeterministic_optimize_skip_unused_shards || sharding_key_is_deterministic;
if (has_sharding_key && sharding_key_is_usable)
{
ClusterPtr optimized = skipUnusedShards(cluster, query_ptr, metadata_snapshot, local_context);
if (optimized)
return optimized;
}
UInt64 force = settings.force_optimize_skip_unused_shards;
if (force)
{
WriteBufferFromOwnString exception_message;
if (!has_sharding_key)
exception_message << "No sharding key";
else if (!sharding_key_is_usable)
exception_message << "Sharding key is not deterministic";
else
exception_message << "Sharding key " << sharding_key_column_name << " is not used";
if (force == FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_ALWAYS)
throw Exception(exception_message.str(), ErrorCodes::UNABLE_TO_SKIP_UNUSED_SHARDS);
if (force == FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_HAS_SHARDING_KEY && has_sharding_key)
throw Exception(exception_message.str(), ErrorCodes::UNABLE_TO_SKIP_UNUSED_SHARDS);
}
return {};
}
IColumn::Selector StorageDistributed::createSelector(const ClusterPtr cluster, const ColumnWithTypeAndName & result)
{
const auto & slot_to_shard = cluster->getSlotToShard();
// If result.type is DataTypeLowCardinality, do shard according to its dictionaryType
#define CREATE_FOR_TYPE(TYPE) \
if (typeid_cast<const DataType##TYPE *>(result.type.get())) \
return createBlockSelector<TYPE>(*result.column, slot_to_shard); \
else if (auto * type_low_cardinality = typeid_cast<const DataTypeLowCardinality *>(result.type.get())) \
if (typeid_cast<const DataType ## TYPE *>(type_low_cardinality->getDictionaryType().get())) \
return createBlockSelector<TYPE>(*result.column->convertToFullColumnIfLowCardinality(), slot_to_shard);
CREATE_FOR_TYPE(UInt8)
CREATE_FOR_TYPE(UInt16)
CREATE_FOR_TYPE(UInt32)
CREATE_FOR_TYPE(UInt64)
CREATE_FOR_TYPE(Int8)
CREATE_FOR_TYPE(Int16)
CREATE_FOR_TYPE(Int32)
CREATE_FOR_TYPE(Int64)
#undef CREATE_FOR_TYPE
throw Exception{"Sharding key expression does not evaluate to an integer type", ErrorCodes::TYPE_MISMATCH};
}
/// Returns a new cluster with fewer shards if constant folding for `sharding_key_expr` is possible
/// using constraints from "PREWHERE" and "WHERE" conditions, otherwise returns `nullptr`
ClusterPtr StorageDistributed::skipUnusedShards(
ClusterPtr cluster,
const ASTPtr & query_ptr,
const StorageMetadataPtr & metadata_snapshot,
ContextPtr local_context) const
{
const auto & select = query_ptr->as<ASTSelectQuery &>();
if (!select.prewhere() && !select.where())
{
return nullptr;
}
ASTPtr condition_ast;
if (select.prewhere() && select.where())
{
condition_ast = makeASTFunction("and", select.prewhere()->clone(), select.where()->clone());
}
else
{
condition_ast = select.prewhere() ? select.prewhere()->clone() : select.where()->clone();
}
replaceConstantExpressions(condition_ast, local_context, metadata_snapshot->getColumns().getAll(), shared_from_this(), metadata_snapshot);
size_t limit = local_context->getSettingsRef().optimize_skip_unused_shards_limit;
if (!limit || limit > SSIZE_MAX)
{
throw Exception("optimize_skip_unused_shards_limit out of range (0, {}]", ErrorCodes::ARGUMENT_OUT_OF_BOUND, SSIZE_MAX);
}
// To interpret limit==0 as limit is reached
++limit;
const auto blocks = evaluateExpressionOverConstantCondition(condition_ast, sharding_key_expr, limit);
if (!limit)
{
LOG_TRACE(log,
"Number of values for sharding key exceeds optimize_skip_unused_shards_limit={}, "
"try to increase it, but note that this may increase query processing time.",
local_context->getSettingsRef().optimize_skip_unused_shards_limit);
return nullptr;
}
// Can't get definite answer if we can skip any shards
if (!blocks)
{
return nullptr;
}
std::set<int> shards;
for (const auto & block : *blocks)
{
if (!block.has(sharding_key_column_name))
throw Exception("sharding_key_expr should evaluate as a single row", ErrorCodes::TOO_MANY_ROWS);
const ColumnWithTypeAndName & result = block.getByName(sharding_key_column_name);
const auto selector = createSelector(cluster, result);
shards.insert(selector.begin(), selector.end());
}
return cluster->getClusterWithMultipleShards({shards.begin(), shards.end()});
}
ActionLock StorageDistributed::getActionLock(StorageActionBlockType type)
{
if (type == ActionLocks::DistributedSend)
return monitors_blocker.cancel();
return {};
}
void StorageDistributed::flushClusterNodesAllData(ContextPtr local_context)
{
/// Sync SYSTEM FLUSH DISTRIBUTED with TRUNCATE
auto table_lock = lockForShare(local_context->getCurrentQueryId(), local_context->getSettingsRef().lock_acquire_timeout);
std::vector<std::shared_ptr<StorageDistributedDirectoryMonitor>> directory_monitors;
{
std::lock_guard lock(cluster_nodes_mutex);
directory_monitors.reserve(cluster_nodes_data.size());
for (auto & node : cluster_nodes_data)
directory_monitors.push_back(node.second.directory_monitor);
}
/// TODO: Maybe it should be executed in parallel
for (auto & node : directory_monitors)
node->flushAllData();
}
void StorageDistributed::rename(const String & new_path_to_table_data, const StorageID & new_table_id)
{
assert(relative_data_path != new_path_to_table_data);
if (!relative_data_path.empty())
renameOnDisk(new_path_to_table_data);
renameInMemory(new_table_id);
}
size_t StorageDistributed::getRandomShardIndex(const Cluster::ShardsInfo & shards)
{
UInt32 total_weight = 0;
for (const auto & shard : shards)
total_weight += shard.weight;
assert(total_weight > 0);
size_t res;
{
std::lock_guard lock(rng_mutex);
res = std::uniform_int_distribution<size_t>(0, total_weight - 1)(rng);
}
for (auto i = 0ul, s = shards.size(); i < s; ++i)
{
if (shards[i].weight > res)
return i;
res -= shards[i].weight;
}
__builtin_unreachable();
}
void StorageDistributed::renameOnDisk(const String & new_path_to_table_data)
{
for (const DiskPtr & disk : data_volume->getDisks())
{
disk->moveDirectory(relative_data_path, new_path_to_table_data);
auto new_path = disk->getPath() + new_path_to_table_data;
LOG_DEBUG(log, "Updating path to {}", new_path);
std::lock_guard lock(cluster_nodes_mutex);
for (auto & node : cluster_nodes_data)
node.second.directory_monitor->updatePath(new_path_to_table_data);
}
relative_data_path = new_path_to_table_data;
}
void StorageDistributed::delayInsertOrThrowIfNeeded() const
{
if (!distributed_settings.bytes_to_throw_insert &&
!distributed_settings.bytes_to_delay_insert)
return;
UInt64 total_bytes = *totalBytes(getContext()->getSettingsRef());
if (distributed_settings.bytes_to_throw_insert && total_bytes > distributed_settings.bytes_to_throw_insert)
{
ProfileEvents::increment(ProfileEvents::DistributedRejectedInserts);
throw Exception(ErrorCodes::DISTRIBUTED_TOO_MANY_PENDING_BYTES,
"Too many bytes pending for async INSERT: {} (bytes_to_throw_insert={})",
formatReadableSizeWithBinarySuffix(total_bytes),
formatReadableSizeWithBinarySuffix(distributed_settings.bytes_to_throw_insert));
}
if (distributed_settings.bytes_to_delay_insert && total_bytes > distributed_settings.bytes_to_delay_insert)
{
/// Step is 5% of the delay and minimal one second.
/// NOTE: max_delay_to_insert is in seconds, and step is in ms.
const size_t step_ms = std::min<double>(1., double(distributed_settings.max_delay_to_insert) * 1'000 * 0.05);
UInt64 delayed_ms = 0;
do {
delayed_ms += step_ms;
std::this_thread::sleep_for(std::chrono::milliseconds(step_ms));
} while (*totalBytes(getContext()->getSettingsRef()) > distributed_settings.bytes_to_delay_insert && delayed_ms < distributed_settings.max_delay_to_insert*1000);
ProfileEvents::increment(ProfileEvents::DistributedDelayedInserts);
ProfileEvents::increment(ProfileEvents::DistributedDelayedInsertsMilliseconds, delayed_ms);
UInt64 new_total_bytes = *totalBytes(getContext()->getSettingsRef());
LOG_INFO(log, "Too many bytes pending for async INSERT: was {}, now {}, INSERT was delayed to {} ms",
formatReadableSizeWithBinarySuffix(total_bytes),
formatReadableSizeWithBinarySuffix(new_total_bytes),
delayed_ms);
if (new_total_bytes > distributed_settings.bytes_to_delay_insert)
{
ProfileEvents::increment(ProfileEvents::DistributedRejectedInserts);
throw Exception(ErrorCodes::DISTRIBUTED_TOO_MANY_PENDING_BYTES,
"Too many bytes pending for async INSERT: {} (bytes_to_delay_insert={})",
formatReadableSizeWithBinarySuffix(new_total_bytes),
formatReadableSizeWithBinarySuffix(distributed_settings.bytes_to_delay_insert));
}
}
}
void registerStorageDistributed(StorageFactory & factory)
{
factory.registerStorage("Distributed", [](const StorageFactory::Arguments & args)
{
/** Arguments of engine is following:
* - name of cluster in configuration;
* - name of remote database;
* - name of remote table;
* - policy to store data in;
*
* Remote database may be specified in following form:
* - identifier;
* - constant expression with string result, like currentDatabase();
* -- string literal as specific case;
* - empty string means 'use default database from cluster'.
*
* Distributed engine also supports SETTINGS clause.
*/
ASTs & engine_args = args.engine_args;
if (engine_args.size() < 3 || engine_args.size() > 5)
throw Exception(
"Storage Distributed requires from 3 to 5 parameters - "
"name of configuration section with list of remote servers, "
"name of remote database, "
"name of remote table, "
"sharding key expression (optional), "
"policy to store data in (optional).",
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
String cluster_name = getClusterNameAndMakeLiteral(engine_args[0]);
engine_args[1] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[1], args.getLocalContext());
engine_args[2] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[2], args.getLocalContext());
String remote_database = engine_args[1]->as<ASTLiteral &>().value.safeGet<String>();
String remote_table = engine_args[2]->as<ASTLiteral &>().value.safeGet<String>();
const auto & sharding_key = engine_args.size() >= 4 ? engine_args[3] : nullptr;
const auto & storage_policy = engine_args.size() >= 5 ? engine_args[4]->as<ASTLiteral &>().value.safeGet<String>() : "default";
/// Check that sharding_key exists in the table and has numeric type.
if (sharding_key)
{
auto sharding_expr = buildShardingKeyExpression(sharding_key, args.getContext(), args.columns.getAllPhysical(), true);
const Block & block = sharding_expr->getSampleBlock();
if (block.columns() != 1)
throw Exception("Sharding expression must return exactly one column", ErrorCodes::INCORRECT_NUMBER_OF_COLUMNS);
auto type = block.getByPosition(0).type;
if (!type->isValueRepresentedByInteger())
throw Exception("Sharding expression has type " + type->getName() +
", but should be one of integer type", ErrorCodes::TYPE_MISMATCH);
}
/// TODO: move some arguments from the arguments to the SETTINGS.
DistributedSettings distributed_settings;
if (args.storage_def->settings)
{
distributed_settings.loadFromQuery(*args.storage_def);
}
if (distributed_settings.max_delay_to_insert < 1)
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND,
"max_delay_to_insert cannot be less then 1");
if (distributed_settings.bytes_to_throw_insert && distributed_settings.bytes_to_delay_insert &&
distributed_settings.bytes_to_throw_insert <= distributed_settings.bytes_to_delay_insert)
{
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND,
"bytes_to_throw_insert cannot be less or equal to bytes_to_delay_insert (since it is handled first)");
}
return StorageDistributed::create(
args.table_id, args.columns, args.constraints,
remote_database, remote_table, cluster_name,
args.getContext(),
sharding_key,
storage_policy,
args.relative_data_path,
distributed_settings,
args.attach);
},
{
.supports_settings = true,
.supports_parallel_insert = true,
.source_access_type = AccessType::REMOTE,
});
}
}