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ClickHouse/src/Storages/StorageDistributed.cpp

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#include <Storages/StorageDistributed.h>
#include <Databases/IDatabase.h>
#include <Disks/IDisk.h>
#include <QueryPipeline/RemoteQueryExecutor.h>
#include <DataTypes/DataTypeFactory.h>
#include <DataTypes/DataTypeUUID.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/ObjectUtils.h>
#include <DataTypes/NestedUtils.h>
#include <Storages/Distributed/DistributedSink.h>
#include <Storages/StorageFactory.h>
#include <Storages/AlterCommands.h>
#include <Storages/getStructureOfRemoteTable.h>
#include <Storages/checkAndGetLiteralArgument.h>
#include <Storages/StorageDummy.h>
#include <Storages/removeGroupingFunctionSpecializations.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 <Common/CurrentMetrics.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTInsertQuery.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/parseQuery.h>
#include <Parsers/IAST.h>
#include <Analyzer/Utils.h>
#include <Analyzer/ColumnNode.h>
#include <Analyzer/FunctionNode.h>
#include <Analyzer/TableNode.h>
#include <Analyzer/TableFunctionNode.h>
#include <Analyzer/QueryNode.h>
#include <Analyzer/JoinNode.h>
#include <Analyzer/QueryTreeBuilder.h>
#include <Analyzer/Passes/QueryAnalysisPass.h>
#include <Analyzer/InDepthQueryTreeVisitor.h>
#include <Analyzer/WindowFunctionsUtils.h>
#include <Planner/Planner.h>
#include <Planner/Utils.h>
#include <Interpreters/ClusterProxy/SelectStreamFactory.h>
#include <Interpreters/ClusterProxy/executeQuery.h>
#include <Interpreters/Cluster.h>
#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Interpreters/ExpressionAnalyzer.h>
#include <Interpreters/InterpreterSelectQuery.h>
#include <Interpreters/InterpreterSelectQueryAnalyzer.h>
#include <Interpreters/InterpreterInsertQuery.h>
#include <Interpreters/JoinedTables.h>
#include <Interpreters/TranslateQualifiedNamesVisitor.h>
#include <Interpreters/AddDefaultDatabaseVisitor.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 <Interpreters/RequiredSourceColumnsVisitor.h>
#include <Interpreters/getCustomKeyFilterForParallelReplicas.h>
#include <Interpreters/getHeaderForProcessingStage.h>
#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <TableFunctions/TableFunctionView.h>
#include <TableFunctions/TableFunctionFactory.h>
#include <Storages/buildQueryTreeForShard.h>
#include <Storages/IStorageCluster.h>
#include <Processors/Executors/PushingPipelineExecutor.h>
#include <Processors/Executors/CompletedPipelineExecutor.h>
#include <Processors/QueryPlan/QueryPlan.h>
#include <Processors/QueryPlan/BuildQueryPipelineSettings.h>
#include <Processors/QueryPlan/ReadFromPreparedSource.h>
#include <Processors/QueryPlan/ExpressionStep.h>
#include <Processors/Sources/NullSource.h>
#include <Processors/Sources/RemoteSource.h>
#include <Processors/Sinks/EmptySink.h>
#include <Core/Settings.h>
#include <Core/SettingsEnums.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromString.h>
#include <IO/Operators.h>
#include <IO/ConnectionTimeouts.h>
#include <Storages/BlockNumberColumn.h>
#include <memory>
#include <filesystem>
#include <optional>
#include <cassert>
namespace fs = std::filesystem;
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 CurrentMetrics
{
extern const Metric StorageDistributedThreads;
extern const Metric StorageDistributedThreadsActive;
extern const Metric StorageDistributedThreadsScheduled;
}
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;
extern const int TOO_LARGE_DISTRIBUTED_DEPTH;
}
namespace ActionLocks
{
extern const StorageActionBlockType DistributedSend;
}
namespace
{
/// 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 isExpressionActionsDeterministic(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 StorageSnapshotPtr & storage_snapshot)
{
auto syntax_result = TreeRewriter(context).analyze(node, columns, storage, storage_snapshot);
Block block_with_constants = KeyCondition::getBlockWithConstants(node, syntax_result, context);
InDepthNodeVisitor<ReplacingConstantExpressionsMatcher, true> visitor(block_with_constants);
visitor.visit(node);
}
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 + num_local_shards) * settings.max_parallel_replicas;
}
}
/// 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<DataTypeLowCardinality>(std::make_shared<DataTypeString>())),
NameAndTypePair("_part", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())),
NameAndTypePair("_part_index", std::make_shared<DataTypeUInt64>()),
NameAndTypePair("_part_uuid", std::make_shared<DataTypeUUID>()),
NameAndTypePair("_partition_id", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())),
NameAndTypePair("_sample_factor", std::make_shared<DataTypeFloat64>()),
NameAndTypePair("_part_offset", std::make_shared<DataTypeUInt64>()),
NameAndTypePair("_row_exists", std::make_shared<DataTypeUInt8>()),
NameAndTypePair(BlockNumberColumn::name, BlockNumberColumn::type),
NameAndTypePair("_shard_num", std::make_shared<DataTypeUInt32>()), /// deprecated
};
}
StorageDistributed::StorageDistributed(
const StorageID & id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
const String & comment,
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_,
ASTPtr remote_table_function_ptr_)
: IStorage(id_)
, WithContext(context_->getGlobalContext())
, remote_database(remote_database_)
, remote_table(remote_table_)
, remote_table_function_ptr(remote_table_function_ptr_)
, 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())
{
if (!distributed_settings.flush_on_detach && distributed_settings.background_insert_batch)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Settings flush_on_detach=0 and background_insert_batch=1 are incompatible");
StorageInMemoryMetadata storage_metadata;
if (columns_.empty())
{
StorageID id = StorageID::createEmpty();
id.table_name = remote_table;
id.database_name = remote_database;
storage_metadata.setColumns(getStructureOfRemoteTable(*getCluster(), id, getContext(), remote_table_function_ptr));
}
else
storage_metadata.setColumns(columns_);
storage_metadata.setConstraints(constraints_);
storage_metadata.setComment(comment);
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 = isExpressionActionsDeterministic(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_)
{
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.");
size_t num_local_shards = getCluster()->getLocalShardCount();
if (num_local_shards && (remote_database.empty() || remote_database == id_.database_name) && remote_table == id_.table_name)
throw Exception(ErrorCodes::INFINITE_LOOP, "Distributed table {} looks at itself", id_.table_name);
}
initializeFromDisk();
}
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{},
String{},
cluster_name_,
context_,
sharding_key_,
storage_policy_name_,
relative_data_path_,
distributed_settings_,
attach,
std::move(owned_cluster_),
remote_table_function_ptr_)
{
}
QueryProcessingStage::Enum StorageDistributed::getQueryProcessingStage(
ContextPtr local_context,
QueryProcessingStage::Enum to_stage,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info) const
{
const auto & settings = local_context->getSettingsRef();
ClusterPtr cluster = getCluster();
size_t nodes = getClusterQueriedNodes(settings, cluster);
if (query_info.use_custom_key)
{
LOG_INFO(log, "Single shard cluster used with custom_key, transforming replicas into virtual shards");
query_info.cluster = cluster->getClusterWithReplicasAsShards(settings, settings.max_parallel_replicas);
}
else
{
query_info.cluster = cluster;
if (nodes > 1 && settings.optimize_skip_unused_shards)
{
/// Always calculate optimized cluster here, to avoid conditions during read()
/// (Anyway it will be calculated in the read())
auto syntax_analyzer_result = query_info.syntax_analyzer_result;
ClusterPtr optimized_cluster = getOptimizedCluster(local_context, storage_snapshot, query_info, syntax_analyzer_result);
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;
nodes = getClusterQueriedNodes(settings, 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)
{
if (settings.distributed_push_down_limit)
return QueryProcessingStage::WithMergeableStateAfterAggregationAndLimit;
else
return QueryProcessingStage::WithMergeableStateAfterAggregation;
}
else
{
/// NOTE: distributed_group_by_no_merge=1 does not respect distributed_push_down_limit
/// (since in this case queries processed separately and the initiator is just a proxy in this case).
if (to_stage != QueryProcessingStage::Complete)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Queries with distributed_group_by_no_merge=1 should be processed to Complete stage");
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 (nodes == 1)
{
/// In case the query was processed to
/// WithMergeableStateAfterAggregation/WithMergeableStateAfterAggregationAndLimit
/// (which are greater the Complete stage)
/// we cannot return Complete (will break aliases and similar),
/// relevant for Distributed over Distributed
return std::max(to_stage, QueryProcessingStage::Complete);
}
else if (nodes == 0)
{
/// In case of 0 shards, the query should be processed fully on the initiator,
/// since we need to apply aggregations.
/// That's why we need to return FetchColumns.
return QueryProcessingStage::FetchColumns;
}
std::optional<QueryProcessingStage::Enum> optimized_stage;
if (settings.allow_experimental_analyzer)
optimized_stage = getOptimizedQueryProcessingStageAnalyzer(query_info, settings);
else
optimized_stage = getOptimizedQueryProcessingStage(query_info, settings);
if (optimized_stage)
{
if (*optimized_stage == QueryProcessingStage::Complete)
return std::min(to_stage, *optimized_stage);
return *optimized_stage;
}
return QueryProcessingStage::WithMergeableState;
}
std::optional<QueryProcessingStage::Enum> StorageDistributed::getOptimizedQueryProcessingStageAnalyzer(const SelectQueryInfo & query_info, const Settings & settings) const
{
bool optimize_sharding_key_aggregation =
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);
QueryProcessingStage::Enum default_stage = QueryProcessingStage::WithMergeableStateAfterAggregation;
if (settings.distributed_push_down_limit)
default_stage = QueryProcessingStage::WithMergeableStateAfterAggregationAndLimit;
const auto & query_node = query_info.query_tree->as<const QueryNode &>();
auto expr_contains_sharding_key = [&](const ListNode & exprs) -> bool
{
std::unordered_set<std::string> expr_columns;
for (const auto & expr : exprs)
{
const auto * id = expr->as<const ColumnNode>();
if (!id)
continue;
auto source = id->getColumnSourceOrNull();
if (!source)
continue;
if (source.get() != query_info.table_expression.get())
continue;
expr_columns.emplace(id->getColumnName());
}
for (const auto & column : sharding_key_expr->getRequiredColumns())
{
if (!expr_columns.contains(column))
return false;
}
return true;
};
// GROUP BY qualifiers
// - TODO: WITH TOTALS can be implemented
// - TODO: WITH ROLLUP can be implemented (I guess)
if (query_node.isGroupByWithTotals() || query_node.isGroupByWithRollup() || query_node.isGroupByWithCube())
return {};
// Window functions are not supported.
if (hasWindowFunctionNodes(query_info.query_tree))
return {};
// TODO: extremes support can be implemented
if (settings.extremes)
return {};
// DISTINCT
if (query_node.isDistinct())
{
if (!optimize_sharding_key_aggregation || !expr_contains_sharding_key(query_node.getProjection()))
return {};
}
// GROUP BY
if (query_info.has_aggregates || query_node.hasGroupBy())
{
if (!optimize_sharding_key_aggregation || !query_node.hasGroupBy() || !expr_contains_sharding_key(query_node.getGroupBy()))
return {};
}
// LIMIT BY
if (query_node.hasLimitBy())
{
if (!optimize_sharding_key_aggregation || !expr_contains_sharding_key(query_node.getLimitBy()))
return {};
}
// ORDER BY
if (query_node.hasOrderBy())
return default_stage;
// LIMIT
// OFFSET
if (query_node.hasLimit() || query_node.hasOffset())
return default_stage;
// Only simple SELECT FROM GROUP BY sharding_key can use Complete state.
return QueryProcessingStage::Complete;
}
std::optional<QueryProcessingStage::Enum> StorageDistributed::getOptimizedQueryProcessingStage(const SelectQueryInfo & query_info, const Settings & settings) const
{
bool optimize_sharding_key_aggregation =
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);
QueryProcessingStage::Enum default_stage = QueryProcessingStage::WithMergeableStateAfterAggregation;
if (settings.distributed_push_down_limit)
default_stage = QueryProcessingStage::WithMergeableStateAfterAggregationAndLimit;
const auto & select = query_info.query->as<ASTSelectQuery &>();
auto expr_contains_sharding_key = [&](const auto & exprs) -> bool
{
std::unordered_set<std::string> expr_columns;
for (auto & expr : exprs)
{
auto id = expr->template as<ASTIdentifier>();
if (!id)
continue;
expr_columns.emplace(id->name());
}
for (const auto & column : sharding_key_expr->getRequiredColumns())
{
if (!expr_columns.contains(column))
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 {};
// Window functions are not supported.
if (query_info.has_window)
return {};
// TODO: extremes support can be implemented
if (settings.extremes)
return {};
// DISTINCT
if (select.distinct)
{
if (!optimize_sharding_key_aggregation || !expr_contains_sharding_key(select.select()->children))
return {};
}
// GROUP BY
const ASTPtr group_by = select.groupBy();
bool has_aggregates = query_info.has_aggregates;
if (query_info.syntax_analyzer_result)
has_aggregates = !query_info.syntax_analyzer_result->aggregates.empty();
if (has_aggregates || group_by)
{
if (!optimize_sharding_key_aggregation || !group_by || !expr_contains_sharding_key(group_by->children))
return {};
}
// LIMIT BY
if (const ASTPtr limit_by = select.limitBy())
{
if (!optimize_sharding_key_aggregation || !expr_contains_sharding_key(limit_by->children))
return {};
}
// ORDER BY
if (const ASTPtr order_by = select.orderBy())
return default_stage;
// LIMIT
// OFFSET
if (select.limitLength() || select.limitOffset())
return default_stage;
// Only simple SELECT FROM GROUP BY sharding_key can use Complete state.
return QueryProcessingStage::Complete;
}
static bool requiresObjectColumns(const ColumnsDescription & all_columns, ASTPtr query)
{
if (!hasDynamicSubcolumns(all_columns))
return false;
if (!query)
return true;
RequiredSourceColumnsVisitor::Data columns_context;
RequiredSourceColumnsVisitor(columns_context).visit(query);
auto required_columns = columns_context.requiredColumns();
for (const auto & required_column : required_columns)
{
auto name_in_storage = Nested::splitName(required_column).first;
auto column_in_storage = all_columns.tryGetPhysical(name_in_storage);
if (column_in_storage && column_in_storage->type->hasDynamicSubcolumns())
return true;
}
return false;
}
StorageSnapshotPtr StorageDistributed::getStorageSnapshot(const StorageMetadataPtr & metadata_snapshot, ContextPtr query_context) const
{
return getStorageSnapshotForQuery(metadata_snapshot, nullptr, query_context);
}
StorageSnapshotPtr StorageDistributed::getStorageSnapshotForQuery(
const StorageMetadataPtr & metadata_snapshot, const ASTPtr & query, ContextPtr /*query_context*/) const
{
/// If query doesn't use columns of type Object, don't deduce
/// concrete types for them, because it required extra round trip.
auto snapshot_data = std::make_unique<SnapshotData>();
if (!requiresObjectColumns(metadata_snapshot->getColumns(), query))
return std::make_shared<StorageSnapshot>(*this, metadata_snapshot, ColumnsDescription{}, std::move(snapshot_data));
snapshot_data->objects_by_shard = getExtendedObjectsOfRemoteTables(
*getCluster(),
StorageID{remote_database, remote_table},
metadata_snapshot->getColumns(),
getContext());
auto object_columns = DB::getConcreteObjectColumns(
snapshot_data->objects_by_shard.begin(),
snapshot_data->objects_by_shard.end(),
metadata_snapshot->getColumns(),
[](const auto & shard_num_and_columns) -> const auto & { return shard_num_and_columns.second; });
return std::make_shared<StorageSnapshot>(*this, metadata_snapshot, std::move(object_columns), std::move(snapshot_data));
}
namespace
{
QueryTreeNodePtr buildQueryTreeDistributed(SelectQueryInfo & query_info,
const StorageSnapshotPtr & distributed_storage_snapshot,
const StorageID & remote_storage_id,
const ASTPtr & remote_table_function)
{
auto & planner_context = query_info.planner_context;
const auto & query_context = planner_context->getQueryContext();
std::optional<TableExpressionModifiers> table_expression_modifiers;
if (auto * query_info_table_node = query_info.table_expression->as<TableNode>())
table_expression_modifiers = query_info_table_node->getTableExpressionModifiers();
else if (auto * query_info_table_function_node = query_info.table_expression->as<TableFunctionNode>())
table_expression_modifiers = query_info_table_function_node->getTableExpressionModifiers();
QueryTreeNodePtr replacement_table_expression;
if (remote_table_function)
{
auto remote_table_function_query_tree = buildQueryTree(remote_table_function, query_context);
auto & remote_table_function_node = remote_table_function_query_tree->as<FunctionNode &>();
auto table_function_node = std::make_shared<TableFunctionNode>(remote_table_function_node.getFunctionName());
table_function_node->getArgumentsNode() = remote_table_function_node.getArgumentsNode();
if (table_expression_modifiers)
table_function_node->setTableExpressionModifiers(*table_expression_modifiers);
QueryAnalysisPass query_analysis_pass;
query_analysis_pass.run(table_function_node, query_context);
replacement_table_expression = std::move(table_function_node);
}
else
{
auto resolved_remote_storage_id = remote_storage_id;
// In case of cross-replication we don't know what database is used for the table.
// `storage_id.hasDatabase()` can return false only on the initiator node.
// Each shard will use the default database (in the case of cross-replication shards may have different defaults).
if (remote_storage_id.hasDatabase())
resolved_remote_storage_id = query_context->resolveStorageID(remote_storage_id);
auto get_column_options = GetColumnsOptions(GetColumnsOptions::All).withExtendedObjects().withVirtuals();
auto column_names_and_types = distributed_storage_snapshot->getColumns(get_column_options);
auto storage = std::make_shared<StorageDummy>(resolved_remote_storage_id, ColumnsDescription{column_names_and_types});
auto table_node = std::make_shared<TableNode>(std::move(storage), query_context);
if (table_expression_modifiers)
table_node->setTableExpressionModifiers(*table_expression_modifiers);
replacement_table_expression = std::move(table_node);
}
replacement_table_expression->setAlias(query_info.table_expression->getAlias());
auto query_tree_to_modify = query_info.query_tree->cloneAndReplace(query_info.table_expression, std::move(replacement_table_expression));
return buildQueryTreeForShard(query_info, query_tree_to_modify);
}
}
void StorageDistributed::read(
QueryPlan & query_plan,
const 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*/)
{
Block header;
ASTPtr query_ast;
if (local_context->getSettingsRef().allow_experimental_analyzer)
{
StorageID remote_storage_id = StorageID::createEmpty();
if (!remote_table_function_ptr)
remote_storage_id = StorageID{remote_database, remote_table};
auto query_tree_distributed = buildQueryTreeDistributed(query_info,
storage_snapshot,
remote_storage_id,
remote_table_function_ptr);
header = InterpreterSelectQueryAnalyzer::getSampleBlock(query_tree_distributed, local_context, SelectQueryOptions(processed_stage).analyze());
/** For distributed tables we do not need constants in header, since we don't send them to remote servers.
* Moreover, constants can break some functions like `hostName` that are constants only for local queries.
*/
for (auto & column : header)
column.column = column.column->convertToFullColumnIfConst();
query_ast = queryNodeToSelectQuery(query_tree_distributed);
}
else
{
header = InterpreterSelectQuery(query_info.query, local_context, SelectQueryOptions(processed_stage).analyze()).getSampleBlock();
query_ast = query_info.query;
}
const auto & modified_query_ast = ClusterProxy::rewriteSelectQuery(
local_context, query_ast,
remote_database, remote_table, remote_table_function_ptr);
/// Return directly (with correct header) if no shard to query.
if (query_info.getCluster()->getShardsInfo().empty())
{
if (local_context->getSettingsRef().allow_experimental_analyzer)
return;
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;
}
StorageID main_table = StorageID::createEmpty();
if (!remote_table_function_ptr)
main_table = StorageID{remote_database, remote_table};
const auto & snapshot_data = assert_cast<const SnapshotData &>(*storage_snapshot->data);
ClusterProxy::SelectStreamFactory select_stream_factory =
ClusterProxy::SelectStreamFactory(
header,
snapshot_data.objects_by_shard,
storage_snapshot,
processed_stage);
auto settings = local_context->getSettingsRef();
ClusterProxy::AdditionalShardFilterGenerator additional_shard_filter_generator;
if (query_info.use_custom_key)
{
if (auto custom_key_ast = parseCustomKeyForTable(settings.parallel_replicas_custom_key, *local_context))
{
if (query_info.getCluster()->getShardCount() == 1)
{
// we are reading from single shard with multiple replicas but didn't transform replicas
// into virtual shards with custom_key set
throw Exception(ErrorCodes::LOGICAL_ERROR, "Replicas weren't transformed into virtual shards");
}
additional_shard_filter_generator =
[&, my_custom_key_ast = std::move(custom_key_ast), shard_count = query_info.cluster->getShardCount()](uint64_t shard_num) -> ASTPtr
{
return getCustomKeyFilterForParallelReplica(
shard_count, shard_num - 1, my_custom_key_ast, settings.parallel_replicas_custom_key_filter_type, *this, local_context);
};
}
}
ClusterProxy::executeQuery(
query_plan, header, processed_stage,
main_table, remote_table_function_ptr,
select_stream_factory, log, modified_query_ast,
local_context, query_info,
sharding_key_expr, sharding_key_column_name,
query_info.cluster, additional_shard_filter_generator);
/// 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(ErrorCodes::LOGICAL_ERROR, "Pipeline is not initialized");
}
SinkToStoragePtr StorageDistributed::write(const ASTPtr &, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context, bool /*async_insert*/)
{
auto cluster = getCluster();
const auto & settings = local_context->getSettingsRef();
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(ErrorCodes::STORAGE_REQUIRES_PARAMETER,
"Method write is not supported by storage {} with more than one shard and no sharding key provided", getName());
}
if (settings.insert_shard_id && settings.insert_shard_id > shard_num)
{
throw Exception(ErrorCodes::INVALID_SHARD_ID, "Shard id should be range from 1 to shard number");
}
/// Force sync insertion if it is remote() table function
bool insert_sync = settings.distributed_foreground_insert || settings.insert_shard_id || owned_cluster;
auto timeout = settings.distributed_background_insert_timeout;
Names columns_to_send;
if (settings.insert_allow_materialized_columns)
columns_to_send = metadata_snapshot->getSampleBlock().getNames();
else
columns_to_send = metadata_snapshot->getSampleBlockNonMaterialized().getNames();
/// DistributedSink will not own cluster, but will own ConnectionPools of the cluster
return std::make_shared<DistributedSink>(
local_context, *this, metadata_snapshot, cluster, insert_sync, timeout,
StorageID{remote_database, remote_table}, columns_to_send);
}
std::optional<QueryPipeline> StorageDistributed::distributedWriteBetweenDistributedTables(const StorageDistributed & src_distributed, const ASTInsertQuery & query, ContextPtr local_context) const
{
const auto & settings = local_context->getSettingsRef();
auto new_query = std::dynamic_pointer_cast<ASTInsertQuery>(query.clone());
/// Unwrap view() function.
if (src_distributed.remote_table_function_ptr)
{
const TableFunctionPtr src_table_function =
TableFunctionFactory::instance().get(src_distributed.remote_table_function_ptr, local_context);
const TableFunctionView * view_function =
assert_cast<const TableFunctionView *>(src_table_function.get());
new_query->select = view_function->getSelectQuery().clone();
}
else
{
const auto select_with_union_query = std::make_shared<ASTSelectWithUnionQuery>();
select_with_union_query->list_of_selects = std::make_shared<ASTExpressionList>();
auto * select = query.select->as<ASTSelectWithUnionQuery &>().list_of_selects->children.at(0)->as<ASTSelectQuery>();
auto new_select_query = std::dynamic_pointer_cast<ASTSelectQuery>(select->clone());
select_with_union_query->list_of_selects->children.push_back(new_select_query);
new_select_query->replaceDatabaseAndTable(src_distributed.getRemoteDatabaseName(), src_distributed.getRemoteTableName());
new_query->select = select_with_union_query;
}
const Cluster::AddressesWithFailover & src_addresses = src_distributed.getCluster()->getShardsAddresses();
const Cluster::AddressesWithFailover & dst_addresses = getCluster()->getShardsAddresses();
/// Compare addresses instead of cluster name, to handle remote()/cluster().
/// (since for remote()/cluster() the getClusterName() is empty string)
if (src_addresses != dst_addresses)
{
/// The warning should be produced only for root queries,
/// since in case of parallel_distributed_insert_select=1,
/// it will produce warning for the rewritten insert,
/// since destination table is still Distributed there.
if (local_context->getClientInfo().distributed_depth == 0)
{
LOG_WARNING(log,
"Parallel distributed INSERT SELECT is not possible "
"(source cluster={} ({} addresses), destination cluster={} ({} addresses))",
src_distributed.getClusterName(),
src_addresses.size(),
getClusterName(),
dst_addresses.size());
}
return {};
}
if (settings.parallel_distributed_insert_select == PARALLEL_DISTRIBUTED_INSERT_SELECT_ALL)
{
new_query->table_id = StorageID(getRemoteDatabaseName(), getRemoteTableName());
/// Reset table function for INSERT INTO remote()/cluster()
new_query->table_function.reset();
}
const auto & cluster = getCluster();
const auto & shards_info = cluster->getShardsInfo();
String new_query_str;
{
WriteBufferFromOwnString buf;
IAST::FormatSettings ast_format_settings(buf, /*one_line*/ true, /*hilite*/ false, /*always_quote_identifiers_=*/ true);
new_query->IAST::format(ast_format_settings);
new_query_str = buf.str();
}
QueryPipeline pipeline;
ContextMutablePtr query_context = Context::createCopy(local_context);
query_context->increaseDistributedDepth();
for (size_t shard_index : collections::range(0, shards_info.size()))
{
const auto & shard_info = shards_info[shard_index];
if (shard_info.isLocal())
{
InterpreterInsertQuery interpreter(new_query, query_context);
pipeline.addCompletedPipeline(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(ErrorCodes::LOGICAL_ERROR, "Expected exactly one connection for shard {}",
shard_info.shard_num);
/// INSERT SELECT query returns empty block
auto remote_query_executor
= std::make_shared<RemoteQueryExecutor>(std::move(connections), new_query_str, Block{}, query_context);
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> StorageDistributed::distributedWriteFromClusterStorage(const IStorageCluster & src_storage_cluster, const ASTInsertQuery & query, ContextPtr local_context) const
{
const auto & settings = local_context->getSettingsRef();
auto & select = query.select->as<ASTSelectWithUnionQuery &>();
/// Select query is needed for pruining on virtual columns
auto extension = src_storage_cluster.getTaskIteratorExtension(
select.list_of_selects->children.at(0)->as<ASTSelectQuery>()->clone(),
local_context);
auto dst_cluster = getCluster();
auto new_query = std::dynamic_pointer_cast<ASTInsertQuery>(query.clone());
if (settings.parallel_distributed_insert_select == PARALLEL_DISTRIBUTED_INSERT_SELECT_ALL)
{
new_query->table_id = StorageID(getRemoteDatabaseName(), getRemoteTableName());
/// Reset table function for INSERT INTO remote()/cluster()
new_query->table_function.reset();
}
String new_query_str;
{
WriteBufferFromOwnString buf;
IAST::FormatSettings ast_format_settings(buf, /*one_line*/ true, /*hilite*/ false, /*always_quote_identifiers*/ true);
new_query->IAST::format(ast_format_settings);
new_query_str = buf.str();
}
QueryPipeline pipeline;
ContextMutablePtr query_context = Context::createCopy(local_context);
query_context->increaseDistributedDepth();
/// Here we take addresses from destination cluster and assume source table exists on these nodes
for (const auto & replicas : getCluster()->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, ssh::SSHKey(), node.quota_key, node.cluster, node.cluster_secret,
"ParallelInsertSelectInititiator",
node.compression,
node.secure
);
auto remote_query_executor = std::make_shared<RemoteQueryExecutor>(
connection,
new_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> StorageDistributed::distributedWrite(const ASTInsertQuery & query, ContextPtr local_context)
{
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;
/// Distributed write only works in the most trivial case INSERT ... SELECT
/// without any unions or joins on the right side
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<StorageDistributed>(src_storage))
{
return distributedWriteBetweenDistributedTables(*src_distributed, query, local_context);
}
if (auto src_storage_cluster = std::dynamic_pointer_cast<IStorageCluster>(src_storage))
{
return distributedWriteFromClusterStorage(*src_storage_cluster, query, local_context);
}
if (local_context->getClientInfo().distributed_depth == 0)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Parallel distributed INSERT SELECT is not possible. "\
"Reason: distributed reading is supported only from Distributed engine "
"or *Cluster table functions, but got {} storage", src_storage->getName());
}
return {};
}
void StorageDistributed::checkAlterIsPossible(const AlterCommands & commands, ContextPtr local_context) const
{
std::optional<NameDependencies> name_deps{};
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 && command.type != AlterCommand::Type::COMMENT_TABLE)
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Alter of type '{}' is not supported by storage {}",
command.type, getName());
if (command.type == AlterCommand::DROP_COLUMN && !command.clear)
{
if (!name_deps)
name_deps = getDependentViewsByColumn(local_context);
const auto & deps_mv = name_deps.value()[command.column_name];
if (!deps_mv.empty())
{
throw Exception(ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN,
"Trying to ALTER DROP column {} which is referenced by materialized view {}",
backQuoteIfNeed(command.column_name), toString(deps_mv));
}
}
}
}
void StorageDistributed::alter(const AlterCommands & params, ContextPtr local_context, AlterLockHolder &)
{
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::initializeFromDisk()
{
if (!storage_policy)
return;
const auto & disks = data_volume->getDisks();
/// Make initialization for large number of disks parallel.
ThreadPool pool(CurrentMetrics::StorageDistributedThreads, CurrentMetrics::StorageDistributedThreadsActive, CurrentMetrics::StorageDistributedThreadsScheduled, disks.size());
for (const DiskPtr & disk : disks)
{
pool.scheduleOrThrowOnError([&]()
{
initializeDirectoryQueuesForDisk(disk);
});
}
pool.wait();
const auto & paths = getDataPaths();
std::vector<UInt64> last_increment(paths.size());
for (size_t i = 0; i < paths.size(); ++i)
{
pool.scheduleOrThrowOnError([&, i]()
{
last_increment[i] = getMaximumFileNumber(paths[i]);
});
}
pool.wait();
for (const auto inc : last_increment)
{
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(bool)
{
async_insert_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
// getDirectoryQueue() 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 not do anything, because ActionBlocker is
// canceled (in shutdown()).
shutdown(true);
// Distributed table without 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)
{
if (!disk->exists(relative_data_path))
{
LOG_INFO(log, "Path {} is already removed from disk {}", relative_data_path, disk->getName());
continue;
}
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_queue->shutdownAndDropAllData();
it = cluster_nodes_data.erase(it);
}
LOG_DEBUG(log, "Removed");
}
StoragePolicyPtr StorageDistributed::getStoragePolicy() const
{
return storage_policy;
}
void StorageDistributed::initializeDirectoryQueuesForDisk(const DiskPtr & disk)
{
const std::string path(disk->getPath() + relative_data_path);
fs::create_directories(path);
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))
{
/// Created by DistributedSink
const auto & tmp_path = dir_path / "tmp";
if (std::filesystem::is_directory(tmp_path) && std::filesystem::is_empty(tmp_path))
std::filesystem::remove(tmp_path);
const auto & broken_path = dir_path / "broken";
if (std::filesystem::is_directory(broken_path) && std::filesystem::is_empty(broken_path))
std::filesystem::remove(broken_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 DistributedSink on demand.
std::filesystem::remove(dir_path);
}
else
{
getDirectoryQueue(disk, dir_path.filename().string());
}
}
}
}
DistributedAsyncInsertDirectoryQueue & StorageDistributed::getDirectoryQueue(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_queue)
{
node_data.connection_pool = DistributedAsyncInsertDirectoryQueue::createPool(name, *this);
node_data.directory_queue = std::make_unique<DistributedAsyncInsertDirectoryQueue>(
*this, disk, relative_data_path + name,
node_data.connection_pool,
async_insert_blocker,
getContext()->getDistributedSchedulePool());
}
return *node_data.directory_queue;
}
std::vector<DistributedAsyncInsertDirectoryQueue::Status> StorageDistributed::getDirectoryQueueStatuses() const
{
std::vector<DistributedAsyncInsertDirectoryQueue::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_queue->getStatus());
return statuses;
}
std::optional<UInt64> StorageDistributed::totalBytes(const Settings &) const
{
UInt64 total_bytes = 0;
for (const auto & status : getDirectoryQueueStatuses())
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 StorageSnapshotPtr & storage_snapshot,
const SelectQueryInfo & query_info,
const TreeRewriterResultPtr & syntax_analyzer_result) 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_info, syntax_analyzer_result, storage_snapshot, local_context);
if (optimized)
return optimized;
}
UInt64 force = settings.force_optimize_skip_unused_shards;
if (force == FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_ALWAYS || (force == FORCE_OPTIMIZE_SKIP_UNUSED_SHARDS_HAS_SHARDING_KEY && has_sharding_key))
{
if (!has_sharding_key)
throw Exception(ErrorCodes::UNABLE_TO_SKIP_UNUSED_SHARDS, "No sharding key");
else if (!sharding_key_is_usable)
throw Exception(ErrorCodes::UNABLE_TO_SKIP_UNUSED_SHARDS, "Sharding key is not deterministic");
else
throw Exception(ErrorCodes::UNABLE_TO_SKIP_UNUSED_SHARDS, "Sharding key {} is not used", sharding_key_column_name);
}
return {};
}
IColumn::Selector StorageDistributed::createSelector(const ClusterPtr cluster, const ColumnWithTypeAndName & result)
{
const auto & slot_to_shard = cluster->getSlotToShard();
const IColumn * column = result.column.get();
if (const auto * col_const = typeid_cast<const ColumnConst *>(column))
column = &col_const->getDataColumn();
// 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>(*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>(*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(ErrorCodes::TYPE_MISMATCH, "Sharding key expression does not evaluate to an integer type");
}
ClusterPtr StorageDistributed::skipUnusedShardsWithAnalyzer(
ClusterPtr cluster,
const SelectQueryInfo & query_info,
[[maybe_unused]] const StorageSnapshotPtr & storage_snapshot,
ContextPtr local_context) const
{
ActionsDAG::NodeRawConstPtrs nodes;
const auto & prewhere_info = query_info.prewhere_info;
if (prewhere_info)
{
{
const auto & node = prewhere_info->prewhere_actions->findInOutputs(prewhere_info->prewhere_column_name);
nodes.push_back(&node);
}
if (prewhere_info->row_level_filter)
{
const auto & node = prewhere_info->row_level_filter->findInOutputs(prewhere_info->row_level_column_name);
nodes.push_back(&node);
}
}
if (query_info.filter_actions_dag)
nodes.push_back(query_info.filter_actions_dag->getOutputs().at(0));
if (nodes.empty())
return nullptr;
auto filter_actions_dag = ActionsDAG::buildFilterActionsDAG(nodes, {}, local_context);
size_t limit = local_context->getSettingsRef().optimize_skip_unused_shards_limit;
if (!limit || limit > SSIZE_MAX)
{
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "optimize_skip_unused_shards_limit out of range (0, {}]", SSIZE_MAX);
}
const auto & sharding_key_dag = sharding_key_expr->getActionsDAG();
const auto * expr_node = sharding_key_dag.tryFindInOutputs(sharding_key_column_name);
if (!expr_node)
throw Exception(
ErrorCodes::LOGICAL_ERROR, "Cannot find sharding key column {} in expression {}",
sharding_key_column_name, sharding_key_dag.dumpDAG());
const auto * predicate = filter_actions_dag->getOutputs().at(0);
const auto variants = evaluateExpressionOverConstantCondition(predicate, {expr_node}, local_context, limit);
// Can't get a definite answer if we can skip any shards
if (!variants)
return nullptr;
std::set<int> shards;
for (const auto & variant : *variants)
{
const auto selector = createSelector(cluster, variant.at(0));
shards.insert(selector.begin(), selector.end());
}
return cluster->getClusterWithMultipleShards({shards.begin(), shards.end()});
}
/// 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 SelectQueryInfo & query_info,
const TreeRewriterResultPtr & syntax_analyzer_result,
const StorageSnapshotPtr & storage_snapshot,
ContextPtr local_context) const
{
if (local_context->getSettingsRef().allow_experimental_analyzer)
return skipUnusedShardsWithAnalyzer(cluster, query_info, storage_snapshot, local_context);
const auto & select = query_info.query->as<ASTSelectQuery &>();
if (!select.prewhere() && !select.where())
return nullptr;
/// FIXME: support analyzer
if (!syntax_analyzer_result)
return nullptr;
ASTPtr condition_ast;
/// Remove JOIN from the query since it may contain a condition for other tables.
/// But only the conditions for the left table should be analyzed for shard skipping.
{
ASTPtr select_without_join_ptr = select.clone();
ASTSelectQuery select_without_join = select_without_join_ptr->as<ASTSelectQuery &>();
TreeRewriterResult analyzer_result_without_join = *syntax_analyzer_result;
removeJoin(select_without_join, analyzer_result_without_join, local_context);
if (!select_without_join.prewhere() && !select_without_join.where())
return nullptr;
if (select_without_join.prewhere() && select_without_join.where())
condition_ast = makeASTFunction("and", select_without_join.prewhere()->clone(), select_without_join.where()->clone());
else
condition_ast = select_without_join.prewhere() ? select_without_join.prewhere()->clone() : select_without_join.where()->clone();
}
replaceConstantExpressions(condition_ast, local_context, storage_snapshot->metadata->getColumns().getAll(), shared_from_this(), storage_snapshot);
size_t limit = local_context->getSettingsRef().optimize_skip_unused_shards_limit;
if (!limit || limit > SSIZE_MAX)
{
throw Exception(ErrorCodes::ARGUMENT_OUT_OF_BOUND, "optimize_skip_unused_shards_limit out of range (0, {}]", SSIZE_MAX);
}
// To interpret limit==0 as limit is reached
++limit;
const auto blocks = evaluateExpressionOverConstantCondition(condition_ast, sharding_key_expr, limit);
if (!limit)
{
LOG_DEBUG(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 a 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(ErrorCodes::TOO_MANY_ROWS, "sharding_key_expr should evaluate as a single row");
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 async_insert_blocker.cancel();
return {};
}
void StorageDistributed::flushAndPrepareForShutdown()
{
try
{
flushClusterNodesAllData(getContext());
}
catch (...)
{
tryLogCurrentException(log, "Cannot flush");
}
}
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<DistributedAsyncInsertDirectoryQueue>> directory_queues;
{
std::lock_guard lock(cluster_nodes_mutex);
directory_queues.reserve(cluster_nodes_data.size());
for (auto & node : cluster_nodes_data)
directory_queues.push_back(node.second.directory_queue);
}
bool need_flush = getDistributedSettingsRef().flush_on_detach;
if (!need_flush)
LOG_INFO(log, "Skip flushing data (due to flush_on_detach=0)");
/// TODO: Maybe it should be executed in parallel
for (auto & node : directory_queues)
{
if (need_flush)
node->flushAllData();
else
node->shutdownWithoutFlush();
}
}
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;
}
UNREACHABLE();
}
void StorageDistributed::renameOnDisk(const String & new_path_to_table_data)
{
for (const DiskPtr & disk : data_volume->getDisks())
{
disk->createDirectories(new_path_to_table_data);
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_queue->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 = static_cast<size_t>(std::min<double>(1., static_cast<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(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
"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).");
String cluster_name = getClusterNameAndMakeLiteral(engine_args[0]);
const ContextPtr & context = args.getContext();
const ContextPtr & local_context = args.getLocalContext();
engine_args[1] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[1], local_context);
engine_args[2] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[2], local_context);
String remote_database = checkAndGetLiteralArgument<String>(engine_args[1], "remote_database");
String remote_table = checkAndGetLiteralArgument<String>(engine_args[2], "remote_table");
const auto & sharding_key = engine_args.size() >= 4 ? engine_args[3] : nullptr;
String storage_policy = "default";
if (engine_args.size() >= 5)
{
engine_args[4] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[4], local_context);
storage_policy = checkAndGetLiteralArgument<String>(engine_args[4], "storage_policy");
}
/// Check that sharding_key exists in the table and has numeric type.
if (sharding_key)
{
auto sharding_expr = buildShardingKeyExpression(sharding_key, context, args.columns.getAllPhysical(), true);
const Block & block = sharding_expr->getSampleBlock();
if (block.columns() != 1)
throw Exception(ErrorCodes::INCORRECT_NUMBER_OF_COLUMNS, "Sharding expression must return exactly one column");
auto type = block.getByPosition(0).type;
if (!type->isValueRepresentedByInteger())
throw Exception(ErrorCodes::TYPE_MISMATCH, "Sharding expression has type {}, but should be one of integer type",
type->getName());
}
/// 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)");
}
/// Set default values from the distributed_background_insert_* global context settings.
if (!distributed_settings.background_insert_batch.changed)
distributed_settings.background_insert_batch = context->getSettingsRef().distributed_background_insert_batch;
if (!distributed_settings.background_insert_split_batch_on_failure.changed)
distributed_settings.background_insert_split_batch_on_failure = context->getSettingsRef().distributed_background_insert_split_batch_on_failure;
if (!distributed_settings.background_insert_sleep_time_ms.changed)
distributed_settings.background_insert_sleep_time_ms = context->getSettingsRef().distributed_background_insert_sleep_time_ms;
if (!distributed_settings.background_insert_max_sleep_time_ms.changed)
distributed_settings.background_insert_max_sleep_time_ms = context->getSettingsRef().distributed_background_insert_max_sleep_time_ms;
return std::make_shared<StorageDistributed>(
args.table_id,
args.columns,
args.constraints,
args.comment,
remote_database,
remote_table,
cluster_name,
context,
sharding_key,
storage_policy,
args.relative_data_path,
distributed_settings,
args.attach);
},
{
.supports_settings = true,
.supports_parallel_insert = true,
.supports_schema_inference = true,
.source_access_type = AccessType::REMOTE,
});
}
bool StorageDistributed::initializeDiskOnConfigChange(const std::set<String> & new_added_disks)
{
if (!data_volume)
return true;
for (auto & disk : data_volume->getDisks())
{
if (new_added_disks.contains(disk->getName()))
{
initializeDirectoryQueuesForDisk(disk);
}
}
return true;
}
}
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