mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-16 03:12:43 +00:00
5611b2fff4
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
1104 lines
44 KiB
C++
1104 lines
44 KiB
C++
#include <QueryPipeline/narrowPipe.h>
|
|
#include <QueryPipeline/QueryPipelineBuilder.h>
|
|
#include <Storages/StorageMerge.h>
|
|
#include <Storages/StorageFactory.h>
|
|
#include <Storages/StorageView.h>
|
|
#include <Storages/VirtualColumnUtils.h>
|
|
#include <Storages/AlterCommands.h>
|
|
#include <Storages/checkAndGetLiteralArgument.h>
|
|
#include <Interpreters/Context.h>
|
|
#include <Interpreters/TreeRewriter.h>
|
|
#include <Interpreters/ExpressionActions.h>
|
|
#include <Interpreters/evaluateConstantExpression.h>
|
|
#include <Interpreters/InterpreterSelectQuery.h>
|
|
#include <Interpreters/InterpreterSelectQueryAnalyzer.h>
|
|
#include <Interpreters/IdentifierSemantic.h>
|
|
#include <Interpreters/getHeaderForProcessingStage.h>
|
|
#include <Interpreters/addTypeConversionToAST.h>
|
|
#include <Interpreters/replaceAliasColumnsInQuery.h>
|
|
#include <Planner/Utils.h>
|
|
#include <Analyzer/Utils.h>
|
|
#include <Analyzer/ConstantNode.h>
|
|
#include <Analyzer/TableNode.h>
|
|
#include <Parsers/ASTFunction.h>
|
|
#include <Parsers/ASTSelectQuery.h>
|
|
#include <Parsers/ASTLiteral.h>
|
|
#include <Parsers/ASTIdentifier.h>
|
|
#include <Parsers/ASTExpressionList.h>
|
|
#include <DataTypes/DataTypeString.h>
|
|
#include <Columns/ColumnString.h>
|
|
#include <Common/typeid_cast.h>
|
|
#include <Common/checkStackSize.h>
|
|
#include "DataTypes/IDataType.h"
|
|
#include <Processors/QueryPlan/ReadFromMergeTree.h>
|
|
#include <Processors/Sources/NullSource.h>
|
|
#include <Processors/QueryPlan/BuildQueryPipelineSettings.h>
|
|
#include <Processors/QueryPlan/Optimizations/QueryPlanOptimizationSettings.h>
|
|
#include <Processors/Transforms/MaterializingTransform.h>
|
|
#include <Processors/ConcatProcessor.h>
|
|
#include <Processors/Transforms/ExpressionTransform.h>
|
|
#include <Processors/QueryPlan/QueryPlan.h>
|
|
#include <Processors/Sources/SourceFromSingleChunk.h>
|
|
#include <Databases/IDatabase.h>
|
|
#include <base/range.h>
|
|
#include <algorithm>
|
|
|
|
|
|
namespace
|
|
{
|
|
|
|
using namespace DB;
|
|
bool columnIsPhysical(ColumnDefaultKind kind)
|
|
{
|
|
return kind == ColumnDefaultKind::Default || kind == ColumnDefaultKind::Materialized;
|
|
}
|
|
bool columnDefaultKindHasSameType(ColumnDefaultKind lhs, ColumnDefaultKind rhs)
|
|
{
|
|
if (lhs == rhs)
|
|
return true;
|
|
|
|
if (columnIsPhysical(lhs) == columnIsPhysical(rhs))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
}
|
|
|
|
namespace DB
|
|
{
|
|
|
|
namespace ErrorCodes
|
|
{
|
|
extern const int BAD_ARGUMENTS;
|
|
extern const int NOT_IMPLEMENTED;
|
|
extern const int ILLEGAL_PREWHERE;
|
|
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
|
|
extern const int SAMPLING_NOT_SUPPORTED;
|
|
extern const int ALTER_OF_COLUMN_IS_FORBIDDEN;
|
|
extern const int CANNOT_EXTRACT_TABLE_STRUCTURE;
|
|
}
|
|
|
|
StorageMerge::StorageMerge(
|
|
const StorageID & table_id_,
|
|
const ColumnsDescription & columns_,
|
|
const String & comment,
|
|
const String & source_database_name_or_regexp_,
|
|
bool database_is_regexp_,
|
|
const DBToTableSetMap & source_databases_and_tables_,
|
|
ContextPtr context_)
|
|
: IStorage(table_id_)
|
|
, WithContext(context_->getGlobalContext())
|
|
, source_database_regexp(source_database_name_or_regexp_)
|
|
, source_databases_and_tables(source_databases_and_tables_)
|
|
, source_database_name_or_regexp(source_database_name_or_regexp_)
|
|
, database_is_regexp(database_is_regexp_)
|
|
{
|
|
StorageInMemoryMetadata storage_metadata;
|
|
storage_metadata.setColumns(columns_.empty() ? getColumnsDescriptionFromSourceTables() : columns_);
|
|
storage_metadata.setComment(comment);
|
|
setInMemoryMetadata(storage_metadata);
|
|
}
|
|
|
|
StorageMerge::StorageMerge(
|
|
const StorageID & table_id_,
|
|
const ColumnsDescription & columns_,
|
|
const String & comment,
|
|
const String & source_database_name_or_regexp_,
|
|
bool database_is_regexp_,
|
|
const String & source_table_regexp_,
|
|
ContextPtr context_)
|
|
: IStorage(table_id_)
|
|
, WithContext(context_->getGlobalContext())
|
|
, source_database_regexp(source_database_name_or_regexp_)
|
|
, source_table_regexp(source_table_regexp_)
|
|
, source_database_name_or_regexp(source_database_name_or_regexp_)
|
|
, database_is_regexp(database_is_regexp_)
|
|
{
|
|
StorageInMemoryMetadata storage_metadata;
|
|
storage_metadata.setColumns(columns_.empty() ? getColumnsDescriptionFromSourceTables() : columns_);
|
|
storage_metadata.setComment(comment);
|
|
setInMemoryMetadata(storage_metadata);
|
|
}
|
|
|
|
ColumnsDescription StorageMerge::getColumnsDescriptionFromSourceTables() const
|
|
{
|
|
auto table = getFirstTable([](auto && t) { return t; });
|
|
if (!table)
|
|
throw Exception{ErrorCodes::CANNOT_EXTRACT_TABLE_STRUCTURE, "There are no tables satisfied provided regexp, you must specify table structure manually"};
|
|
return table->getInMemoryMetadataPtr()->getColumns();
|
|
}
|
|
|
|
template <typename F>
|
|
StoragePtr StorageMerge::getFirstTable(F && predicate) const
|
|
{
|
|
auto database_table_iterators = getDatabaseIterators(getContext());
|
|
|
|
for (auto & iterator : database_table_iterators)
|
|
{
|
|
while (iterator->isValid())
|
|
{
|
|
const auto & table = iterator->table();
|
|
if (table.get() != this && predicate(table))
|
|
return table;
|
|
|
|
iterator->next();
|
|
}
|
|
}
|
|
|
|
return {};
|
|
}
|
|
|
|
template <typename F>
|
|
void StorageMerge::forEachTable(F && func) const
|
|
{
|
|
getFirstTable([&func](const auto & table)
|
|
{
|
|
func(table);
|
|
return false;
|
|
});
|
|
}
|
|
|
|
bool StorageMerge::isRemote() const
|
|
{
|
|
auto first_remote_table = getFirstTable([](const StoragePtr & table) { return table && table->isRemote(); });
|
|
return first_remote_table != nullptr;
|
|
}
|
|
|
|
bool StorageMerge::tableSupportsPrewhere() const
|
|
{
|
|
/// NOTE: This check is used during query analysis as condition for applying
|
|
/// "move to PREWHERE" optimization. However, it contains a logical race:
|
|
/// If new table that matches regexp for current storage and doesn't support PREWHERE
|
|
/// will appear after this check and before calling "read" method, the optimized query may fail.
|
|
/// Since it's quite rare case, we just ignore this possibility.
|
|
///
|
|
/// NOTE: Type can be different, and in this case, PREWHERE cannot be
|
|
/// applied for those columns, but there a separate method to return
|
|
/// supported columns for PREWHERE - supportedPrewhereColumns().
|
|
return getFirstTable([](const auto & table) { return !table->canMoveConditionsToPrewhere(); }) == nullptr;
|
|
}
|
|
|
|
bool StorageMerge::canMoveConditionsToPrewhere() const
|
|
{
|
|
return tableSupportsPrewhere();
|
|
}
|
|
|
|
std::optional<NameSet> StorageMerge::supportedPrewhereColumns() const
|
|
{
|
|
bool supports_prewhere = true;
|
|
|
|
const auto & metadata = getInMemoryMetadata();
|
|
const auto & columns = metadata.getColumns();
|
|
|
|
NameSet supported_columns;
|
|
|
|
std::unordered_map<std::string, std::pair<const IDataType *, ColumnDefaultKind>> column_info;
|
|
for (const auto & name_type : columns.getAll())
|
|
{
|
|
const auto & column_default = columns.getDefault(name_type.name).value_or(ColumnDefault{});
|
|
column_info.emplace(name_type.name, std::make_pair(
|
|
name_type.type.get(),
|
|
column_default.kind));
|
|
supported_columns.emplace(name_type.name);
|
|
}
|
|
|
|
forEachTable([&](const StoragePtr & table)
|
|
{
|
|
const auto & table_metadata_ptr = table->getInMemoryMetadataPtr();
|
|
if (!table_metadata_ptr)
|
|
supports_prewhere = false;
|
|
if (!supports_prewhere)
|
|
return;
|
|
|
|
const auto & table_columns = table_metadata_ptr->getColumns();
|
|
for (const auto & column : table_columns.getAll())
|
|
{
|
|
const auto & column_default = table_columns.getDefault(column.name).value_or(ColumnDefault{});
|
|
const auto & [root_type, src_default_kind] = column_info[column.name];
|
|
if ((root_type && !root_type->equals(*column.type)) ||
|
|
!columnDefaultKindHasSameType(src_default_kind, column_default.kind))
|
|
{
|
|
supported_columns.erase(column.name);
|
|
}
|
|
}
|
|
});
|
|
|
|
return supported_columns;
|
|
}
|
|
|
|
bool StorageMerge::mayBenefitFromIndexForIn(const ASTPtr & left_in_operand, ContextPtr query_context, const StorageMetadataPtr & /*metadata_snapshot*/) const
|
|
{
|
|
/// It's beneficial if it is true for at least one table.
|
|
StorageListWithLocks selected_tables = getSelectedTables(query_context);
|
|
|
|
size_t i = 0;
|
|
for (const auto & table : selected_tables)
|
|
{
|
|
const auto & storage_ptr = std::get<1>(table);
|
|
auto metadata_snapshot = storage_ptr->getInMemoryMetadataPtr();
|
|
if (storage_ptr->mayBenefitFromIndexForIn(left_in_operand, query_context, metadata_snapshot))
|
|
return true;
|
|
|
|
++i;
|
|
/// For simplicity reasons, check only first ten tables.
|
|
if (i > 10)
|
|
break;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
QueryProcessingStage::Enum StorageMerge::getQueryProcessingStage(
|
|
ContextPtr local_context,
|
|
QueryProcessingStage::Enum to_stage,
|
|
const StorageSnapshotPtr &,
|
|
SelectQueryInfo & query_info) const
|
|
{
|
|
/// In case of JOIN the first stage (which includes JOIN)
|
|
/// should be done on the initiator always.
|
|
///
|
|
/// Since in case of JOIN query on shards will receive query without JOIN (and their columns).
|
|
/// (see removeJoin())
|
|
///
|
|
/// And for this we need to return FetchColumns.
|
|
if (const auto * select = query_info.query->as<ASTSelectQuery>(); select && hasJoin(*select))
|
|
return QueryProcessingStage::FetchColumns;
|
|
|
|
auto stage_in_source_tables = QueryProcessingStage::FetchColumns;
|
|
|
|
DatabaseTablesIterators database_table_iterators = getDatabaseIterators(local_context);
|
|
|
|
size_t selected_table_size = 0;
|
|
|
|
/// TODO: Find a way to support projections for StorageMerge
|
|
query_info.ignore_projections = true;
|
|
for (const auto & iterator : database_table_iterators)
|
|
{
|
|
while (iterator->isValid())
|
|
{
|
|
const auto & table = iterator->table();
|
|
if (table && table.get() != this)
|
|
{
|
|
++selected_table_size;
|
|
stage_in_source_tables = std::max(
|
|
stage_in_source_tables,
|
|
table->getQueryProcessingStage(local_context, to_stage,
|
|
table->getStorageSnapshot(table->getInMemoryMetadataPtr(), local_context), query_info));
|
|
}
|
|
|
|
iterator->next();
|
|
}
|
|
}
|
|
|
|
return selected_table_size == 1 ? stage_in_source_tables : std::min(stage_in_source_tables, QueryProcessingStage::WithMergeableState);
|
|
}
|
|
|
|
void StorageMerge::read(
|
|
QueryPlan & query_plan,
|
|
const Names & column_names,
|
|
const StorageSnapshotPtr & storage_snapshot,
|
|
SelectQueryInfo & query_info,
|
|
ContextPtr local_context,
|
|
QueryProcessingStage::Enum processed_stage,
|
|
const size_t max_block_size,
|
|
size_t num_streams)
|
|
{
|
|
/** Just in case, turn off optimization "transfer to PREWHERE",
|
|
* since there is no certainty that it works when one of table is MergeTree and other is not.
|
|
*/
|
|
auto modified_context = Context::createCopy(local_context);
|
|
modified_context->setSetting("optimize_move_to_prewhere", false);
|
|
|
|
bool has_database_virtual_column = false;
|
|
bool has_table_virtual_column = false;
|
|
Names real_column_names;
|
|
real_column_names.reserve(column_names.size());
|
|
|
|
for (const auto & column_name : column_names)
|
|
{
|
|
if (column_name == "_database" && isVirtualColumn(column_name, storage_snapshot->metadata))
|
|
has_database_virtual_column = true;
|
|
else if (column_name == "_table" && isVirtualColumn(column_name, storage_snapshot->metadata))
|
|
has_table_virtual_column = true;
|
|
else
|
|
real_column_names.push_back(column_name);
|
|
}
|
|
|
|
StorageListWithLocks selected_tables
|
|
= getSelectedTables(modified_context, query_info.query, has_database_virtual_column, has_table_virtual_column);
|
|
|
|
InputOrderInfoPtr input_sorting_info;
|
|
if (query_info.order_optimizer)
|
|
{
|
|
for (auto it = selected_tables.begin(); it != selected_tables.end(); ++it)
|
|
{
|
|
auto storage_ptr = std::get<1>(*it);
|
|
auto storage_metadata_snapshot = storage_ptr->getInMemoryMetadataPtr();
|
|
auto current_info = query_info.order_optimizer->getInputOrder(storage_metadata_snapshot, modified_context);
|
|
if (it == selected_tables.begin())
|
|
input_sorting_info = current_info;
|
|
else if (!current_info || (input_sorting_info && *current_info != *input_sorting_info))
|
|
input_sorting_info.reset();
|
|
|
|
if (!input_sorting_info)
|
|
break;
|
|
}
|
|
|
|
query_info.input_order_info = input_sorting_info;
|
|
}
|
|
|
|
query_plan.addInterpreterContext(modified_context);
|
|
|
|
/// What will be result structure depending on query processed stage in source tables?
|
|
Block common_header = getHeaderForProcessingStage(column_names, storage_snapshot, query_info, local_context, processed_stage);
|
|
|
|
auto step = std::make_unique<ReadFromMerge>(
|
|
common_header,
|
|
std::move(selected_tables),
|
|
real_column_names,
|
|
has_database_virtual_column,
|
|
has_table_virtual_column,
|
|
max_block_size,
|
|
num_streams,
|
|
shared_from_this(),
|
|
storage_snapshot,
|
|
query_info,
|
|
std::move(modified_context),
|
|
processed_stage);
|
|
|
|
query_plan.addStep(std::move(step));
|
|
}
|
|
|
|
ReadFromMerge::ReadFromMerge(
|
|
Block common_header_,
|
|
StorageListWithLocks selected_tables_,
|
|
Names column_names_,
|
|
bool has_database_virtual_column_,
|
|
bool has_table_virtual_column_,
|
|
size_t max_block_size,
|
|
size_t num_streams,
|
|
StoragePtr storage,
|
|
StorageSnapshotPtr storage_snapshot,
|
|
const SelectQueryInfo & query_info_,
|
|
ContextMutablePtr context_,
|
|
QueryProcessingStage::Enum processed_stage)
|
|
: SourceStepWithFilter(DataStream{.header = common_header_})
|
|
, required_max_block_size(max_block_size)
|
|
, requested_num_streams(num_streams)
|
|
, common_header(std::move(common_header_))
|
|
, selected_tables(std::move(selected_tables_))
|
|
, column_names(std::move(column_names_))
|
|
, has_database_virtual_column(has_database_virtual_column_)
|
|
, has_table_virtual_column(has_table_virtual_column_)
|
|
, storage_merge(std::move(storage))
|
|
, merge_storage_snapshot(std::move(storage_snapshot))
|
|
, query_info(query_info_)
|
|
, context(std::move(context_))
|
|
, common_processed_stage(processed_stage)
|
|
{
|
|
}
|
|
|
|
void ReadFromMerge::initializePipeline(QueryPipelineBuilder & pipeline, const BuildQueryPipelineSettings &)
|
|
{
|
|
if (selected_tables.empty())
|
|
{
|
|
pipeline.init(Pipe(std::make_shared<NullSource>(output_stream->header)));
|
|
return;
|
|
}
|
|
|
|
size_t tables_count = selected_tables.size();
|
|
Float64 num_streams_multiplier
|
|
= std::min(static_cast<size_t>(tables_count), std::max(1UL, static_cast<size_t>(context->getSettingsRef().max_streams_multiplier_for_merge_tables)));
|
|
size_t num_streams = static_cast<size_t>(requested_num_streams * num_streams_multiplier);
|
|
size_t remaining_streams = num_streams;
|
|
|
|
if (order_info)
|
|
{
|
|
query_info.input_order_info = order_info;
|
|
}
|
|
else if (query_info.order_optimizer)
|
|
{
|
|
InputOrderInfoPtr input_sorting_info;
|
|
for (auto it = selected_tables.begin(); it != selected_tables.end(); ++it)
|
|
{
|
|
auto storage_ptr = std::get<1>(*it);
|
|
auto storage_metadata_snapshot = storage_ptr->getInMemoryMetadataPtr();
|
|
auto current_info = query_info.order_optimizer->getInputOrder(storage_metadata_snapshot, context);
|
|
if (it == selected_tables.begin())
|
|
input_sorting_info = current_info;
|
|
else if (!current_info || (input_sorting_info && *current_info != *input_sorting_info))
|
|
input_sorting_info.reset();
|
|
|
|
if (!input_sorting_info)
|
|
break;
|
|
}
|
|
|
|
query_info.input_order_info = input_sorting_info;
|
|
}
|
|
|
|
auto sample_block = merge_storage_snapshot->getMetadataForQuery()->getSampleBlock();
|
|
|
|
std::vector<std::unique_ptr<QueryPipelineBuilder>> pipelines;
|
|
QueryPlanResourceHolder resources;
|
|
|
|
for (const auto & table : selected_tables)
|
|
{
|
|
size_t current_need_streams = tables_count >= num_streams ? 1 : (num_streams / tables_count);
|
|
size_t current_streams = std::min(current_need_streams, remaining_streams);
|
|
remaining_streams -= current_streams;
|
|
current_streams = std::max(1uz, current_streams);
|
|
|
|
const auto & storage = std::get<1>(table);
|
|
|
|
bool sampling_requested = query_info.query->as<ASTSelectQuery>()->sampleSize() != nullptr;
|
|
if (query_info.table_expression_modifiers)
|
|
sampling_requested = query_info.table_expression_modifiers->hasSampleSizeRatio();
|
|
|
|
/// If sampling requested, then check that table supports it.
|
|
if (sampling_requested && !storage->supportsSampling())
|
|
throw Exception(ErrorCodes::SAMPLING_NOT_SUPPORTED, "Illegal SAMPLE: table doesn't support sampling");
|
|
|
|
Aliases aliases;
|
|
auto storage_metadata_snapshot = storage->getInMemoryMetadataPtr();
|
|
auto nested_storage_snaphsot = storage->getStorageSnapshot(storage_metadata_snapshot, context);
|
|
|
|
auto modified_query_info = getModifiedQueryInfo(query_info, context, table, nested_storage_snaphsot);
|
|
Names column_names_as_aliases;
|
|
|
|
if (!context->getSettingsRef().allow_experimental_analyzer)
|
|
{
|
|
auto storage_columns = storage_metadata_snapshot->getColumns();
|
|
auto syntax_result = TreeRewriter(context).analyzeSelect(
|
|
modified_query_info.query, TreeRewriterResult({}, storage, nested_storage_snaphsot));
|
|
|
|
bool with_aliases = common_processed_stage == QueryProcessingStage::FetchColumns && !storage_columns.getAliases().empty();
|
|
if (with_aliases)
|
|
{
|
|
ASTPtr required_columns_expr_list = std::make_shared<ASTExpressionList>();
|
|
ASTPtr column_expr;
|
|
|
|
for (const auto & column : column_names)
|
|
{
|
|
const auto column_default = storage_columns.getDefault(column);
|
|
bool is_alias = column_default && column_default->kind == ColumnDefaultKind::Alias;
|
|
|
|
if (is_alias)
|
|
{
|
|
column_expr = column_default->expression->clone();
|
|
replaceAliasColumnsInQuery(column_expr, storage_metadata_snapshot->getColumns(),
|
|
syntax_result->array_join_result_to_source, context);
|
|
|
|
auto column_description = storage_columns.get(column);
|
|
column_expr = addTypeConversionToAST(std::move(column_expr), column_description.type->getName(),
|
|
storage_metadata_snapshot->getColumns().getAll(), context);
|
|
column_expr = setAlias(column_expr, column);
|
|
|
|
auto type = sample_block.getByName(column).type;
|
|
aliases.push_back({ .name = column, .type = type, .expression = column_expr->clone() });
|
|
}
|
|
else
|
|
column_expr = std::make_shared<ASTIdentifier>(column);
|
|
|
|
required_columns_expr_list->children.emplace_back(std::move(column_expr));
|
|
}
|
|
|
|
syntax_result = TreeRewriter(context).analyze(
|
|
required_columns_expr_list, storage_columns.getAllPhysical(), storage, storage->getStorageSnapshot(storage_metadata_snapshot, context));
|
|
|
|
auto alias_actions = ExpressionAnalyzer(required_columns_expr_list, syntax_result, context).getActionsDAG(true);
|
|
|
|
column_names_as_aliases = alias_actions->getRequiredColumns().getNames();
|
|
if (column_names_as_aliases.empty())
|
|
column_names_as_aliases.push_back(ExpressionActions::getSmallestColumn(storage_metadata_snapshot->getColumns().getAllPhysical()).name);
|
|
}
|
|
}
|
|
|
|
auto source_pipeline = createSources(
|
|
nested_storage_snaphsot,
|
|
modified_query_info,
|
|
common_processed_stage,
|
|
required_max_block_size,
|
|
common_header,
|
|
aliases,
|
|
table,
|
|
column_names_as_aliases.empty() ? column_names : column_names_as_aliases,
|
|
context,
|
|
current_streams);
|
|
|
|
if (source_pipeline && source_pipeline->initialized())
|
|
{
|
|
resources.storage_holders.push_back(std::get<1>(table));
|
|
resources.table_locks.push_back(std::get<2>(table));
|
|
|
|
pipelines.emplace_back(std::move(source_pipeline));
|
|
}
|
|
}
|
|
|
|
if (pipelines.empty())
|
|
{
|
|
pipeline.init(Pipe(std::make_shared<NullSource>(output_stream->header)));
|
|
return;
|
|
}
|
|
|
|
pipeline = QueryPipelineBuilder::unitePipelines(std::move(pipelines));
|
|
|
|
if (!query_info.input_order_info)
|
|
// It's possible to have many tables read from merge, resize(num_streams) might open too many files at the same time.
|
|
// Using narrowPipe instead. But in case of reading in order of primary key, we cannot do it,
|
|
// because narrowPipe doesn't preserve order.
|
|
pipeline.narrow(num_streams);
|
|
|
|
pipeline.addResources(std::move(resources));
|
|
}
|
|
|
|
SelectQueryInfo ReadFromMerge::getModifiedQueryInfo(const SelectQueryInfo & query_info,
|
|
const ContextPtr & modified_context,
|
|
const StorageWithLockAndName & storage_with_lock_and_name,
|
|
const StorageSnapshotPtr & storage_snapshot)
|
|
{
|
|
const auto & [database_name, storage, storage_lock, table_name] = storage_with_lock_and_name;
|
|
const StorageID current_storage_id = storage->getStorageID();
|
|
|
|
SelectQueryInfo modified_query_info = query_info;
|
|
|
|
if (modified_query_info.table_expression)
|
|
{
|
|
auto replacement_table_expression = std::make_shared<TableNode>(storage, storage_lock, storage_snapshot);
|
|
if (query_info.table_expression_modifiers)
|
|
replacement_table_expression->setTableExpressionModifiers(*query_info.table_expression_modifiers);
|
|
|
|
modified_query_info.query_tree = modified_query_info.query_tree->cloneAndReplace(modified_query_info.table_expression,
|
|
replacement_table_expression);
|
|
modified_query_info.table_expression = replacement_table_expression;
|
|
modified_query_info.planner_context->getOrCreateTableExpressionData(replacement_table_expression);
|
|
|
|
auto get_column_options = GetColumnsOptions(GetColumnsOptions::All).withExtendedObjects().withVirtuals();
|
|
if (storage_snapshot->storage.supportsSubcolumns())
|
|
get_column_options.withSubcolumns();
|
|
|
|
std::unordered_map<std::string, QueryTreeNodePtr> column_name_to_node;
|
|
|
|
if (!storage_snapshot->tryGetColumn(get_column_options, "_table"))
|
|
column_name_to_node.emplace("_table", std::make_shared<ConstantNode>(current_storage_id.table_name));
|
|
|
|
if (!storage_snapshot->tryGetColumn(get_column_options, "_database"))
|
|
column_name_to_node.emplace("_database", std::make_shared<ConstantNode>(current_storage_id.database_name));
|
|
|
|
if (!column_name_to_node.empty())
|
|
{
|
|
replaceColumns(modified_query_info.query_tree,
|
|
replacement_table_expression,
|
|
column_name_to_node);
|
|
}
|
|
|
|
modified_query_info.query = queryNodeToSelectQuery(modified_query_info.query_tree);
|
|
}
|
|
else
|
|
{
|
|
bool is_storage_merge_engine = storage->as<StorageMerge>();
|
|
modified_query_info.query = query_info.query->clone();
|
|
|
|
/// Original query could contain JOIN but we need only the first joined table and its columns.
|
|
auto & modified_select = modified_query_info.query->as<ASTSelectQuery &>();
|
|
TreeRewriterResult new_analyzer_res = *modified_query_info.syntax_analyzer_result;
|
|
removeJoin(modified_select, new_analyzer_res, modified_context);
|
|
modified_query_info.syntax_analyzer_result = std::make_shared<TreeRewriterResult>(std::move(new_analyzer_res));
|
|
|
|
if (!is_storage_merge_engine)
|
|
{
|
|
VirtualColumnUtils::rewriteEntityInAst(modified_query_info.query, "_table", current_storage_id.table_name);
|
|
VirtualColumnUtils::rewriteEntityInAst(modified_query_info.query, "_database", current_storage_id.database_name);
|
|
}
|
|
}
|
|
|
|
return modified_query_info;
|
|
}
|
|
|
|
QueryPipelineBuilderPtr ReadFromMerge::createSources(
|
|
const StorageSnapshotPtr & storage_snapshot,
|
|
SelectQueryInfo & modified_query_info,
|
|
const QueryProcessingStage::Enum & processed_stage,
|
|
const UInt64 max_block_size,
|
|
const Block & header,
|
|
const Aliases & aliases,
|
|
const StorageWithLockAndName & storage_with_lock,
|
|
Names real_column_names,
|
|
ContextMutablePtr modified_context,
|
|
size_t streams_num,
|
|
bool concat_streams)
|
|
{
|
|
const auto & [database_name, storage, _, table_name] = storage_with_lock;
|
|
auto & modified_select = modified_query_info.query->as<ASTSelectQuery &>();
|
|
|
|
QueryPipelineBuilderPtr builder;
|
|
if (!InterpreterSelectQuery::isQueryWithFinal(modified_query_info) && storage->needRewriteQueryWithFinal(real_column_names))
|
|
{
|
|
/// NOTE: It may not work correctly in some cases, because query was analyzed without final.
|
|
/// However, it's needed for MaterializedMySQL and it's unlikely that someone will use it with Merge tables.
|
|
modified_select.setFinal();
|
|
}
|
|
|
|
bool allow_experimental_analyzer = modified_context->getSettingsRef().allow_experimental_analyzer;
|
|
|
|
auto storage_stage = storage->getQueryProcessingStage(modified_context,
|
|
QueryProcessingStage::Complete,
|
|
storage_snapshot,
|
|
modified_query_info);
|
|
|
|
if (processed_stage <= storage_stage || (allow_experimental_analyzer && processed_stage == QueryProcessingStage::FetchColumns))
|
|
{
|
|
/// If there are only virtual columns in query, you must request at least one other column.
|
|
if (real_column_names.empty())
|
|
real_column_names.push_back(ExpressionActions::getSmallestColumn(storage_snapshot->metadata->getColumns().getAllPhysical()).name);
|
|
|
|
QueryPlan & plan = child_plans.emplace_back();
|
|
|
|
StorageView * view = dynamic_cast<StorageView *>(storage.get());
|
|
if (!view || allow_experimental_analyzer)
|
|
{
|
|
storage->read(plan,
|
|
real_column_names,
|
|
storage_snapshot,
|
|
modified_query_info,
|
|
modified_context,
|
|
processed_stage,
|
|
max_block_size,
|
|
UInt32(streams_num));
|
|
}
|
|
else
|
|
{
|
|
/// For view storage, we need to rewrite the `modified_query_info.view_query` to optimize read.
|
|
/// The most intuitive way is to use InterpreterSelectQuery.
|
|
|
|
/// Intercept the settings
|
|
modified_context->setSetting("max_threads", streams_num);
|
|
modified_context->setSetting("max_streams_to_max_threads_ratio", 1);
|
|
modified_context->setSetting("max_block_size", max_block_size);
|
|
|
|
InterpreterSelectQuery interpreter(modified_query_info.query,
|
|
modified_context,
|
|
storage,
|
|
view->getInMemoryMetadataPtr(),
|
|
SelectQueryOptions(processed_stage));
|
|
interpreter.buildQueryPlan(plan);
|
|
}
|
|
|
|
if (!plan.isInitialized())
|
|
return {};
|
|
|
|
if (auto * read_from_merge_tree = typeid_cast<ReadFromMergeTree *>(plan.getRootNode()->step.get()))
|
|
{
|
|
size_t filters_dags_size = filter_dags.size();
|
|
for (size_t i = 0; i < filters_dags_size; ++i)
|
|
read_from_merge_tree->addFilter(filter_dags[i], filter_nodes.nodes[i]);
|
|
}
|
|
|
|
builder = plan.buildQueryPipeline(
|
|
QueryPlanOptimizationSettings::fromContext(modified_context),
|
|
BuildQueryPipelineSettings::fromContext(modified_context));
|
|
}
|
|
else if (processed_stage > storage_stage || (allow_experimental_analyzer && processed_stage != QueryProcessingStage::FetchColumns))
|
|
{
|
|
/// Maximum permissible parallelism is streams_num
|
|
modified_context->setSetting("max_threads", streams_num);
|
|
modified_context->setSetting("max_streams_to_max_threads_ratio", 1);
|
|
|
|
QueryPlan & plan = child_plans.emplace_back();
|
|
|
|
if (allow_experimental_analyzer)
|
|
{
|
|
InterpreterSelectQueryAnalyzer interpreter(modified_query_info.query_tree,
|
|
modified_context,
|
|
SelectQueryOptions(processed_stage).ignoreProjections());
|
|
builder = std::make_unique<QueryPipelineBuilder>(interpreter.buildQueryPipeline());
|
|
plan = std::move(interpreter.getPlanner()).extractQueryPlan();
|
|
}
|
|
else
|
|
{
|
|
modified_select.replaceDatabaseAndTable(database_name, table_name);
|
|
/// TODO: Find a way to support projections for StorageMerge
|
|
InterpreterSelectQuery interpreter{modified_query_info.query,
|
|
modified_context,
|
|
SelectQueryOptions(processed_stage).ignoreProjections()};
|
|
builder = std::make_unique<QueryPipelineBuilder>(interpreter.buildQueryPipeline(plan));
|
|
}
|
|
|
|
/** Materialization is needed, since from distributed storage the constants come materialized.
|
|
* If you do not do this, different types (Const and non-Const) columns will be produced in different threads,
|
|
* And this is not allowed, since all code is based on the assumption that in the block stream all types are the same.
|
|
*/
|
|
builder->addSimpleTransform([](const Block & stream_header) { return std::make_shared<MaterializingTransform>(stream_header); });
|
|
}
|
|
|
|
if (builder->initialized())
|
|
{
|
|
if (concat_streams && builder->getNumStreams() > 1)
|
|
{
|
|
// It's possible to have many tables read from merge, resize(1) might open too many files at the same time.
|
|
// Using concat instead.
|
|
builder->addTransform(std::make_shared<ConcatProcessor>(builder->getHeader(), builder->getNumStreams()));
|
|
}
|
|
|
|
/// Add virtual columns if we don't already have them.
|
|
|
|
Block pipe_header = builder->getHeader();
|
|
|
|
if (has_database_virtual_column && !pipe_header.has("_database"))
|
|
{
|
|
ColumnWithTypeAndName column;
|
|
column.name = "_database";
|
|
column.type = std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>());
|
|
column.column = column.type->createColumnConst(0, Field(database_name));
|
|
|
|
auto adding_column_dag = ActionsDAG::makeAddingColumnActions(std::move(column));
|
|
auto adding_column_actions = std::make_shared<ExpressionActions>(
|
|
std::move(adding_column_dag),
|
|
ExpressionActionsSettings::fromContext(modified_context, CompileExpressions::yes));
|
|
|
|
builder->addSimpleTransform([&](const Block & stream_header)
|
|
{
|
|
return std::make_shared<ExpressionTransform>(stream_header, adding_column_actions);
|
|
});
|
|
}
|
|
|
|
if (has_table_virtual_column && !pipe_header.has("_table"))
|
|
{
|
|
ColumnWithTypeAndName column;
|
|
column.name = "_table";
|
|
column.type = std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>());
|
|
column.column = column.type->createColumnConst(0, Field(table_name));
|
|
|
|
auto adding_column_dag = ActionsDAG::makeAddingColumnActions(std::move(column));
|
|
auto adding_column_actions = std::make_shared<ExpressionActions>(
|
|
std::move(adding_column_dag),
|
|
ExpressionActionsSettings::fromContext(modified_context, CompileExpressions::yes));
|
|
|
|
builder->addSimpleTransform([&](const Block & stream_header)
|
|
{
|
|
return std::make_shared<ExpressionTransform>(stream_header, adding_column_actions);
|
|
});
|
|
}
|
|
|
|
/// Subordinary tables could have different but convertible types, like numeric types of different width.
|
|
/// We must return streams with structure equals to structure of Merge table.
|
|
convertingSourceStream(header, storage_snapshot->metadata, aliases, modified_context, *builder, processed_stage);
|
|
}
|
|
|
|
return builder;
|
|
}
|
|
|
|
StorageMerge::StorageListWithLocks StorageMerge::getSelectedTables(
|
|
ContextPtr query_context,
|
|
const ASTPtr & query /* = nullptr */,
|
|
bool filter_by_database_virtual_column /* = false */,
|
|
bool filter_by_table_virtual_column /* = false */) const
|
|
{
|
|
/// FIXME: filtering does not work with allow_experimental_analyzer due to
|
|
/// different column names there (it has "table_name._table" not just
|
|
/// "_table")
|
|
|
|
assert(!filter_by_database_virtual_column || !filter_by_table_virtual_column || query);
|
|
|
|
const Settings & settings = query_context->getSettingsRef();
|
|
StorageListWithLocks selected_tables;
|
|
DatabaseTablesIterators database_table_iterators = getDatabaseIterators(getContext());
|
|
|
|
MutableColumnPtr database_name_virtual_column;
|
|
MutableColumnPtr table_name_virtual_column;
|
|
if (filter_by_database_virtual_column)
|
|
{
|
|
database_name_virtual_column = ColumnString::create();
|
|
}
|
|
|
|
if (filter_by_table_virtual_column)
|
|
{
|
|
table_name_virtual_column = ColumnString::create();
|
|
}
|
|
|
|
for (const auto & iterator : database_table_iterators)
|
|
{
|
|
if (filter_by_database_virtual_column)
|
|
database_name_virtual_column->insert(iterator->databaseName());
|
|
while (iterator->isValid())
|
|
{
|
|
StoragePtr storage = iterator->table();
|
|
if (!storage)
|
|
continue;
|
|
|
|
if (query && query->as<ASTSelectQuery>()->prewhere() && !storage->supportsPrewhere())
|
|
throw Exception(ErrorCodes::ILLEGAL_PREWHERE, "Storage {} doesn't support PREWHERE.", storage->getName());
|
|
|
|
if (storage.get() != this)
|
|
{
|
|
auto table_lock = storage->lockForShare(query_context->getCurrentQueryId(), settings.lock_acquire_timeout);
|
|
selected_tables.emplace_back(iterator->databaseName(), storage, std::move(table_lock), iterator->name());
|
|
if (filter_by_table_virtual_column)
|
|
table_name_virtual_column->insert(iterator->name());
|
|
}
|
|
|
|
iterator->next();
|
|
}
|
|
}
|
|
|
|
if (filter_by_database_virtual_column)
|
|
{
|
|
/// Filter names of selected tables if there is a condition on "_database" virtual column in WHERE clause
|
|
Block virtual_columns_block
|
|
= Block{ColumnWithTypeAndName(std::move(database_name_virtual_column), std::make_shared<DataTypeString>(), "_database")};
|
|
VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, query_context);
|
|
auto values = VirtualColumnUtils::extractSingleValueFromBlock<String>(virtual_columns_block, "_database");
|
|
|
|
/// Remove unused databases from the list
|
|
selected_tables.remove_if([&](const auto & elem) { return values.find(std::get<0>(elem)) == values.end(); });
|
|
}
|
|
|
|
if (filter_by_table_virtual_column)
|
|
{
|
|
/// Filter names of selected tables if there is a condition on "_table" virtual column in WHERE clause
|
|
Block virtual_columns_block = Block{ColumnWithTypeAndName(std::move(table_name_virtual_column), std::make_shared<DataTypeString>(), "_table")};
|
|
VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, query_context);
|
|
auto values = VirtualColumnUtils::extractSingleValueFromBlock<String>(virtual_columns_block, "_table");
|
|
|
|
/// Remove unused tables from the list
|
|
selected_tables.remove_if([&](const auto & elem) { return values.find(std::get<3>(elem)) == values.end(); });
|
|
}
|
|
|
|
return selected_tables;
|
|
}
|
|
|
|
DatabaseTablesIteratorPtr StorageMerge::getDatabaseIterator(const String & database_name, ContextPtr local_context) const
|
|
{
|
|
auto database = DatabaseCatalog::instance().getDatabase(database_name);
|
|
|
|
auto table_name_match = [this, database_name](const String & table_name_) -> bool
|
|
{
|
|
if (source_databases_and_tables)
|
|
{
|
|
if (auto it = source_databases_and_tables->find(database_name); it != source_databases_and_tables->end())
|
|
return it->second.contains(table_name_);
|
|
else
|
|
return false;
|
|
}
|
|
else
|
|
return source_table_regexp->match(table_name_);
|
|
};
|
|
|
|
return database->getTablesIterator(local_context, table_name_match);
|
|
}
|
|
|
|
StorageMerge::DatabaseTablesIterators StorageMerge::getDatabaseIterators(ContextPtr local_context) const
|
|
{
|
|
try
|
|
{
|
|
checkStackSize();
|
|
}
|
|
catch (Exception & e)
|
|
{
|
|
e.addMessage("while getting table iterator of Merge table. Maybe caused by two Merge tables that will endlessly try to read each other's data");
|
|
throw;
|
|
}
|
|
|
|
DatabaseTablesIterators database_table_iterators;
|
|
|
|
/// database_name argument is not a regexp
|
|
if (!database_is_regexp)
|
|
database_table_iterators.emplace_back(getDatabaseIterator(source_database_name_or_regexp, local_context));
|
|
|
|
/// database_name argument is a regexp
|
|
else
|
|
{
|
|
auto databases = DatabaseCatalog::instance().getDatabases();
|
|
|
|
for (const auto & db : databases)
|
|
{
|
|
if (source_database_regexp->match(db.first))
|
|
database_table_iterators.emplace_back(getDatabaseIterator(db.first, local_context));
|
|
}
|
|
}
|
|
|
|
return database_table_iterators;
|
|
}
|
|
|
|
|
|
void StorageMerge::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::COMMENT_TABLE)
|
|
throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Alter of type '{}' is not supported by storage {}",
|
|
command.type, getName());
|
|
|
|
if (command.type == AlterCommand::Type::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 StorageMerge::alter(
|
|
const AlterCommands & params, ContextPtr local_context, AlterLockHolder &)
|
|
{
|
|
auto table_id = getStorageID();
|
|
|
|
StorageInMemoryMetadata storage_metadata = getInMemoryMetadata();
|
|
params.apply(storage_metadata, local_context);
|
|
DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(local_context, table_id, storage_metadata);
|
|
setInMemoryMetadata(storage_metadata);
|
|
}
|
|
|
|
void ReadFromMerge::convertingSourceStream(
|
|
const Block & header,
|
|
const StorageMetadataPtr & metadata_snapshot,
|
|
const Aliases & aliases,
|
|
ContextPtr local_context,
|
|
QueryPipelineBuilder & builder,
|
|
const QueryProcessingStage::Enum & processed_stage)
|
|
{
|
|
Block before_block_header = builder.getHeader();
|
|
|
|
auto storage_sample_block = metadata_snapshot->getSampleBlock();
|
|
auto pipe_columns = builder.getHeader().getNamesAndTypesList();
|
|
|
|
for (const auto & alias : aliases)
|
|
{
|
|
pipe_columns.emplace_back(NameAndTypePair(alias.name, alias.type));
|
|
ASTPtr expr = alias.expression;
|
|
auto syntax_result = TreeRewriter(local_context).analyze(expr, pipe_columns);
|
|
auto expression_analyzer = ExpressionAnalyzer{alias.expression, syntax_result, local_context};
|
|
|
|
auto dag = std::make_shared<ActionsDAG>(pipe_columns);
|
|
auto actions_dag = expression_analyzer.getActionsDAG(true, false);
|
|
auto actions = std::make_shared<ExpressionActions>(actions_dag, ExpressionActionsSettings::fromContext(local_context, CompileExpressions::yes));
|
|
|
|
builder.addSimpleTransform([&](const Block & stream_header)
|
|
{
|
|
return std::make_shared<ExpressionTransform>(stream_header, actions);
|
|
});
|
|
}
|
|
|
|
ActionsDAG::MatchColumnsMode convert_actions_match_columns_mode = ActionsDAG::MatchColumnsMode::Name;
|
|
|
|
if (local_context->getSettingsRef().allow_experimental_analyzer && processed_stage != QueryProcessingStage::FetchColumns)
|
|
convert_actions_match_columns_mode = ActionsDAG::MatchColumnsMode::Position;
|
|
|
|
auto convert_actions_dag = ActionsDAG::makeConvertingActions(builder.getHeader().getColumnsWithTypeAndName(),
|
|
header.getColumnsWithTypeAndName(),
|
|
convert_actions_match_columns_mode);
|
|
auto actions = std::make_shared<ExpressionActions>(
|
|
std::move(convert_actions_dag),
|
|
ExpressionActionsSettings::fromContext(local_context, CompileExpressions::yes));
|
|
|
|
builder.addSimpleTransform([&](const Block & stream_header)
|
|
{
|
|
return std::make_shared<ExpressionTransform>(stream_header, actions);
|
|
});
|
|
}
|
|
|
|
bool ReadFromMerge::requestReadingInOrder(InputOrderInfoPtr order_info_)
|
|
{
|
|
/// Disable read-in-order optimization for reverse order with final.
|
|
/// Otherwise, it can lead to incorrect final behavior because the implementation may rely on the reading in direct order).
|
|
if (order_info_->direction != 1 && InterpreterSelectQuery::isQueryWithFinal(query_info))
|
|
return false;
|
|
|
|
order_info = order_info_;
|
|
return true;
|
|
}
|
|
|
|
IStorage::ColumnSizeByName StorageMerge::getColumnSizes() const
|
|
{
|
|
ColumnSizeByName column_sizes;
|
|
|
|
forEachTable([&](const auto & table)
|
|
{
|
|
for (const auto & [name, size] : table->getColumnSizes())
|
|
column_sizes[name].add(size);
|
|
});
|
|
|
|
return column_sizes;
|
|
}
|
|
|
|
|
|
std::tuple<bool /* is_regexp */, ASTPtr> StorageMerge::evaluateDatabaseName(const ASTPtr & node, ContextPtr context_)
|
|
{
|
|
if (const auto * func = node->as<ASTFunction>(); func && func->name == "REGEXP")
|
|
{
|
|
if (func->arguments->children.size() != 1)
|
|
throw Exception(ErrorCodes::BAD_ARGUMENTS, "REGEXP in Merge ENGINE takes only one argument");
|
|
|
|
auto * literal = func->arguments->children[0]->as<ASTLiteral>();
|
|
if (!literal || literal->value.getType() != Field::Types::Which::String || literal->value.safeGet<String>().empty())
|
|
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Argument for REGEXP in Merge ENGINE should be a non empty String Literal");
|
|
|
|
return {true, func->arguments->children[0]};
|
|
}
|
|
|
|
auto ast = evaluateConstantExpressionForDatabaseName(node, context_);
|
|
return {false, ast};
|
|
}
|
|
|
|
|
|
void registerStorageMerge(StorageFactory & factory)
|
|
{
|
|
factory.registerStorage("Merge", [](const StorageFactory::Arguments & args)
|
|
{
|
|
/** In query, the name of database is specified as table engine argument which contains source tables,
|
|
* as well as regex for source-table names.
|
|
*/
|
|
|
|
ASTs & engine_args = args.engine_args;
|
|
|
|
if (engine_args.size() != 2)
|
|
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
|
|
"Storage Merge requires exactly 2 parameters - name "
|
|
"of source database and regexp for table names.");
|
|
|
|
auto [is_regexp, database_ast] = StorageMerge::evaluateDatabaseName(engine_args[0], args.getLocalContext());
|
|
|
|
if (!is_regexp)
|
|
engine_args[0] = database_ast;
|
|
|
|
String source_database_name_or_regexp = checkAndGetLiteralArgument<String>(database_ast, "database_name");
|
|
|
|
engine_args[1] = evaluateConstantExpressionAsLiteral(engine_args[1], args.getLocalContext());
|
|
String table_name_regexp = checkAndGetLiteralArgument<String>(engine_args[1], "table_name_regexp");
|
|
|
|
return std::make_shared<StorageMerge>(
|
|
args.table_id, args.columns, args.comment, source_database_name_or_regexp, is_regexp, table_name_regexp, args.getContext());
|
|
},
|
|
{
|
|
.supports_schema_inference = true
|
|
});
|
|
}
|
|
|
|
NamesAndTypesList StorageMerge::getVirtuals() const
|
|
{
|
|
NamesAndTypesList virtuals{
|
|
{"_database", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())},
|
|
{"_table", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())}};
|
|
|
|
auto first_table = getFirstTable([](auto && table) { return table; });
|
|
if (first_table)
|
|
{
|
|
auto table_virtuals = first_table->getVirtuals();
|
|
virtuals.insert(virtuals.end(), table_virtuals.begin(), table_virtuals.end());
|
|
}
|
|
|
|
return virtuals;
|
|
}
|
|
|
|
}
|