ClickHouse/src/Interpreters/ExpressionAnalyzer.cpp

2332 lines
92 KiB
C++

#include <memory>
#include <Core/Block.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTOrderByElement.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSubquery.h>
#include <Parsers/ASTWindowDefinition.h>
#include <Parsers/DumpASTNode.h>
#include <Parsers/ASTInterpolateElement.h>
#include <DataTypes/DataTypeNullable.h>
#include <Columns/IColumn.h>
#include <Interpreters/Aggregator.h>
#include <Interpreters/ArrayJoinAction.h>
#include <Interpreters/Context.h>
#include <Interpreters/ConcurrentHashJoin.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Interpreters/ExpressionActions.h>
#include <Interpreters/ExpressionAnalyzer.h>
#include <Interpreters/ExternalDictionariesLoader.h>
#include <Interpreters/GraceHashJoin.h>
#include <Interpreters/HashJoin.h>
#include <Interpreters/JoinSwitcher.h>
#include <Interpreters/MergeJoin.h>
#include <Interpreters/DirectJoin.h>
#include <Interpreters/Set.h>
#include <Interpreters/TableJoin.h>
#include <Interpreters/FullSortingMergeJoin.h>
#include <Interpreters/replaceForPositionalArguments.h>
#include <Processors/QueryPlan/ExpressionStep.h>
#include <Processors/QueryPlan/AggregatingStep.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <AggregateFunctions/parseAggregateFunctionParameters.h>
#include <Storages/StorageDistributed.h>
#include <Storages/StorageDictionary.h>
#include <Storages/StorageJoin.h>
#include <Functions/FunctionsExternalDictionaries.h>
#include <Dictionaries/DictionaryStructure.h>
#include <Common/typeid_cast.h>
#include <Common/StringUtils/StringUtils.h>
#include <Columns/ColumnNullable.h>
#include <Core/ColumnsWithTypeAndName.h>
#include <DataTypes/IDataType.h>
#include <Core/SettingsEnums.h>
#include <Core/ColumnNumbers.h>
#include <Core/Names.h>
#include <Core/NamesAndTypes.h>
#include <Common/logger_useful.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeFactory.h>
#include <DataTypes/DataTypeFixedString.h>
#include <Interpreters/ActionsVisitor.h>
#include <Interpreters/GetAggregatesVisitor.h>
#include <Interpreters/GlobalSubqueriesVisitor.h>
#include <Interpreters/interpretSubquery.h>
#include <Interpreters/JoinUtils.h>
#include <Interpreters/misc.h>
#include <IO/Operators.h>
#include <IO/WriteBufferFromString.h>
#include <Processors/Executors/PullingAsyncPipelineExecutor.h>
#include <Processors/QueryPlan/QueryPlan.h>
#include <Parsers/formatAST.h>
#include <Parsers/QueryParameterVisitor.h>
namespace DB
{
using LogAST = DebugASTLog<false>; /// set to true to enable logs
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
extern const int ILLEGAL_PREWHERE;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int ILLEGAL_TYPE_OF_COLUMN_FOR_FILTER;
extern const int LOGICAL_ERROR;
extern const int NOT_IMPLEMENTED;
extern const int UNKNOWN_IDENTIFIER;
extern const int UNKNOWN_TYPE_OF_AST_NODE;
}
namespace
{
/// Check if there is an ignore function. It's used for disabling constant folding in query
/// predicates because some performance tests use ignore function as a non-optimize guard.
bool allowEarlyConstantFolding(const ActionsDAG & actions, const Settings & settings)
{
if (!settings.enable_early_constant_folding)
return false;
for (const auto & node : actions.getNodes())
{
if (node.type == ActionsDAG::ActionType::FUNCTION && node.function_base)
{
if (!node.function_base->isSuitableForConstantFolding())
return false;
}
}
return true;
}
Poco::Logger * getLogger() { return &Poco::Logger::get("ExpressionAnalyzer"); }
}
bool sanitizeBlock(Block & block, bool throw_if_cannot_create_column)
{
for (auto & col : block)
{
if (!col.column)
{
if (isNotCreatable(col.type->getTypeId()))
{
if (throw_if_cannot_create_column)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Cannot create column of type {}", col.type->getName());
return false;
}
col.column = col.type->createColumn();
}
else if (!col.column->empty())
col.column = col.column->cloneEmpty();
}
return true;
}
ExpressionAnalyzerData::~ExpressionAnalyzerData() = default;
ExpressionAnalyzer::ExtractedSettings::ExtractedSettings(const Settings & settings_)
: use_index_for_in_with_subqueries(settings_.use_index_for_in_with_subqueries)
, size_limits_for_set(settings_.max_rows_in_set, settings_.max_bytes_in_set, settings_.set_overflow_mode)
, distributed_group_by_no_merge(settings_.distributed_group_by_no_merge)
{}
ExpressionAnalyzer::~ExpressionAnalyzer() = default;
ExpressionAnalyzer::ExpressionAnalyzer(
const ASTPtr & query_,
const TreeRewriterResultPtr & syntax_analyzer_result_,
ContextPtr context_,
size_t subquery_depth_,
bool do_global,
bool is_explain,
PreparedSetsPtr prepared_sets_,
bool is_create_parameterized_view_)
: WithContext(context_)
, query(query_), settings(getContext()->getSettings())
, subquery_depth(subquery_depth_)
, syntax(syntax_analyzer_result_)
, is_create_parameterized_view(is_create_parameterized_view_)
{
/// Cache prepared sets because we might run analysis multiple times
if (prepared_sets_)
prepared_sets = prepared_sets_;
else
prepared_sets = std::make_shared<PreparedSets>();
/// external_tables, sets for global subqueries.
/// Replaces global subqueries with the generated names of temporary tables that will be sent to remote servers.
initGlobalSubqueriesAndExternalTables(do_global, is_explain);
auto temp_actions = std::make_shared<ActionsDAG>(sourceColumns());
columns_after_array_join = getColumnsAfterArrayJoin(temp_actions, sourceColumns());
columns_after_join = analyzeJoin(temp_actions, columns_after_array_join);
/// has_aggregation, aggregation_keys, aggregate_descriptions, aggregated_columns.
/// This analysis should be performed after processing global subqueries, because otherwise,
/// if the aggregate function contains a global subquery, then `analyzeAggregation` method will save
/// in `aggregate_descriptions` the information about the parameters of this aggregate function, among which
/// global subquery. Then, when you call `initGlobalSubqueriesAndExternalTables` method, this
/// the global subquery will be replaced with a temporary table, resulting in aggregate_descriptions
/// will contain out-of-date information, which will lead to an error when the query is executed.
analyzeAggregation(temp_actions);
}
NamesAndTypesList ExpressionAnalyzer::getColumnsAfterArrayJoin(ActionsDAGPtr & actions, const NamesAndTypesList & src_columns)
{
const auto * select_query = query->as<ASTSelectQuery>();
if (!select_query)
return {};
auto [array_join_expression_list, is_array_join_left] = select_query->arrayJoinExpressionList();
if (!array_join_expression_list)
return src_columns;
getRootActionsNoMakeSet(array_join_expression_list, actions, false);
auto array_join = addMultipleArrayJoinAction(actions, is_array_join_left);
auto sample_columns = actions->getResultColumns();
array_join->prepare(sample_columns);
actions = std::make_shared<ActionsDAG>(sample_columns);
NamesAndTypesList new_columns_after_array_join;
NameSet added_columns;
for (auto & column : actions->getResultColumns())
{
if (syntax->array_join_result_to_source.contains(column.name))
{
new_columns_after_array_join.emplace_back(column.name, column.type);
added_columns.emplace(column.name);
}
}
for (const auto & column : src_columns)
if (!added_columns.contains(column.name))
new_columns_after_array_join.emplace_back(column.name, column.type);
return new_columns_after_array_join;
}
NamesAndTypesList ExpressionAnalyzer::analyzeJoin(ActionsDAGPtr & actions, const NamesAndTypesList & src_columns)
{
const auto * select_query = query->as<ASTSelectQuery>();
if (!select_query)
return {};
const ASTTablesInSelectQueryElement * join = select_query->join();
if (join)
{
getRootActionsNoMakeSet(analyzedJoin().leftKeysList(), actions, false);
auto sample_columns = actions->getNamesAndTypesList();
syntax->analyzed_join->addJoinedColumnsAndCorrectTypes(sample_columns, true);
actions = std::make_shared<ActionsDAG>(sample_columns);
}
NamesAndTypesList result_columns = src_columns;
syntax->analyzed_join->addJoinedColumnsAndCorrectTypes(result_columns, false);
return result_columns;
}
void ExpressionAnalyzer::analyzeAggregation(ActionsDAGPtr & temp_actions)
{
/** Find aggregation keys (aggregation_keys), information about aggregate functions (aggregate_descriptions),
* as well as a set of columns obtained after the aggregation, if any,
* or after all the actions that are usually performed before aggregation (aggregated_columns).
*
* Everything below (compiling temporary ExpressionActions) - only for the purpose of query analysis (type output).
*/
auto * select_query = query->as<ASTSelectQuery>();
makeAggregateDescriptions(temp_actions, aggregate_descriptions);
has_aggregation = !aggregate_descriptions.empty() || (select_query && select_query->groupBy());
if (!has_aggregation)
{
aggregated_columns = temp_actions->getNamesAndTypesList();
return;
}
/// Find out aggregation keys.
if (select_query)
{
if (ASTPtr group_by_ast = select_query->groupBy())
{
NameToIndexMap unique_keys;
ASTs & group_asts = group_by_ast->children;
if (select_query->group_by_with_rollup)
group_by_kind = GroupByKind::ROLLUP;
else if (select_query->group_by_with_cube)
group_by_kind = GroupByKind::CUBE;
else if (select_query->group_by_with_grouping_sets && group_asts.size() > 1)
group_by_kind = GroupByKind::GROUPING_SETS;
else
group_by_kind = GroupByKind::ORDINARY;
bool use_nulls = group_by_kind != GroupByKind::ORDINARY && getContext()->getSettingsRef().group_by_use_nulls;
/// For GROUPING SETS with multiple groups we always add virtual __grouping_set column
/// With set number, which is used as an additional key at the stage of merging aggregating data.
if (group_by_kind != GroupByKind::ORDINARY)
aggregated_columns.emplace_back("__grouping_set", std::make_shared<DataTypeUInt64>());
for (ssize_t i = 0; i < static_cast<ssize_t>(group_asts.size()); ++i)
{
ssize_t size = group_asts.size();
if (getContext()->getSettingsRef().enable_positional_arguments)
replaceForPositionalArguments(group_asts[i], select_query, ASTSelectQuery::Expression::GROUP_BY);
if (select_query->group_by_with_grouping_sets)
{
ASTs group_elements_ast;
const ASTExpressionList * group_ast_element = group_asts[i]->as<const ASTExpressionList>();
group_elements_ast = group_ast_element->children;
NamesAndTypesList grouping_set_list;
ColumnNumbers grouping_set_indexes_list;
for (ssize_t j = 0; j < ssize_t(group_elements_ast.size()); ++j)
{
getRootActionsNoMakeSet(group_elements_ast[j], temp_actions, false);
ssize_t group_size = group_elements_ast.size();
const auto & column_name = group_elements_ast[j]->getColumnName();
const auto * node = temp_actions->tryFindInOutputs(column_name);
if (!node)
throw Exception(ErrorCodes::UNKNOWN_IDENTIFIER, "Unknown identifier (in GROUP BY): {}", column_name);
/// Only removes constant keys if it's an initiator or distributed_group_by_no_merge is enabled.
if (getContext()->getClientInfo().distributed_depth == 0 || settings.distributed_group_by_no_merge > 0)
{
/// Constant expressions have non-null column pointer at this stage.
if (node->column && isColumnConst(*node->column))
{
select_query->group_by_with_constant_keys = true;
/// But don't remove last key column if no aggregate functions, otherwise aggregation will not work.
if (!aggregate_descriptions.empty() || group_size > 1)
{
if (j + 1 < static_cast<ssize_t>(group_size))
group_elements_ast[j] = std::move(group_elements_ast.back());
group_elements_ast.pop_back();
--j;
continue;
}
}
}
NameAndTypePair key{column_name, use_nulls ? makeNullableSafe(node->result_type) : node->result_type };
grouping_set_list.push_back(key);
/// Aggregation keys are unique.
if (!unique_keys.contains(key.name))
{
unique_keys[key.name] = aggregation_keys.size();
grouping_set_indexes_list.push_back(aggregation_keys.size());
aggregation_keys.push_back(key);
/// Key is no longer needed, therefore we can save a little by moving it.
aggregated_columns.push_back(std::move(key));
}
else
{
grouping_set_indexes_list.push_back(unique_keys[key.name]);
}
}
aggregation_keys_list.push_back(std::move(grouping_set_list));
aggregation_keys_indexes_list.push_back(std::move(grouping_set_indexes_list));
}
else
{
getRootActionsNoMakeSet(group_asts[i], temp_actions, false);
const auto & column_name = group_asts[i]->getColumnName();
const auto * node = temp_actions->tryFindInOutputs(column_name);
if (!node)
throw Exception(ErrorCodes::UNKNOWN_IDENTIFIER, "Unknown identifier (in GROUP BY): {}", column_name);
/// Only removes constant keys if it's an initiator or distributed_group_by_no_merge is enabled.
if (getContext()->getClientInfo().distributed_depth == 0 || settings.distributed_group_by_no_merge > 0)
{
/// Constant expressions have non-null column pointer at this stage.
if (node->column && isColumnConst(*node->column))
{
select_query->group_by_with_constant_keys = true;
/// But don't remove last key column if no aggregate functions, otherwise aggregation will not work.
if (!aggregate_descriptions.empty() || size > 1)
{
if (i + 1 < static_cast<ssize_t>(size))
group_asts[i] = std::move(group_asts.back());
group_asts.pop_back();
--i;
continue;
}
}
}
NameAndTypePair key = NameAndTypePair{ column_name, use_nulls ? makeNullableSafe(node->result_type) : node->result_type };
/// Aggregation keys are uniqued.
if (!unique_keys.contains(key.name))
{
unique_keys[key.name] = aggregation_keys.size();
aggregation_keys.push_back(key);
/// Key is no longer needed, therefore we can save a little by moving it.
aggregated_columns.push_back(std::move(key));
}
}
}
if (!select_query->group_by_with_grouping_sets)
{
auto & list = aggregation_keys_indexes_list.emplace_back();
for (size_t i = 0; i < aggregation_keys.size(); ++i)
list.push_back(i);
}
if (group_asts.empty())
{
select_query->setExpression(ASTSelectQuery::Expression::GROUP_BY, {});
has_aggregation = !aggregate_descriptions.empty();
}
}
/// Constant expressions are already removed during first 'analyze' run.
/// So for second `analyze` information is taken from select_query.
has_const_aggregation_keys = select_query->group_by_with_constant_keys;
}
else
aggregated_columns = temp_actions->getNamesAndTypesList();
for (const auto & desc : aggregate_descriptions)
aggregated_columns.emplace_back(desc.column_name, desc.function->getResultType());
}
void ExpressionAnalyzer::initGlobalSubqueriesAndExternalTables(bool do_global, bool is_explain)
{
if (do_global)
{
GlobalSubqueriesVisitor::Data subqueries_data(
getContext(), subquery_depth, isRemoteStorage(), is_explain, external_tables, prepared_sets, has_global_subqueries);
GlobalSubqueriesVisitor(subqueries_data).visit(query);
}
}
void ExpressionAnalyzer::tryMakeSetForIndexFromSubquery(const ASTPtr & subquery_or_table_name, const SelectQueryOptions & query_options)
{
if (!prepared_sets)
return;
auto set_key = PreparedSetKey::forSubquery(*subquery_or_table_name);
if (prepared_sets->get(set_key))
return; /// Already prepared.
if (auto set_ptr_from_storage_set = isPlainStorageSetInSubquery(subquery_or_table_name))
{
prepared_sets->set(set_key, set_ptr_from_storage_set);
return;
}
auto interpreter_subquery = interpretSubquery(subquery_or_table_name, getContext(), {}, query_options);
auto io = interpreter_subquery->execute();
PullingAsyncPipelineExecutor executor(io.pipeline);
SetPtr set = std::make_shared<Set>(settings.size_limits_for_set, true, getContext()->getSettingsRef().transform_null_in);
set->setHeader(executor.getHeader().getColumnsWithTypeAndName());
Block block;
while (executor.pull(block))
{
if (block.rows() == 0)
continue;
/// If the limits have been exceeded, give up and let the default subquery processing actions take place.
if (!set->insertFromBlock(block.getColumnsWithTypeAndName()))
return;
}
set->finishInsert();
prepared_sets->set(set_key, std::move(set));
}
SetPtr ExpressionAnalyzer::isPlainStorageSetInSubquery(const ASTPtr & subquery_or_table_name)
{
const auto * table = subquery_or_table_name->as<ASTTableIdentifier>();
if (!table)
return nullptr;
auto table_id = getContext()->resolveStorageID(subquery_or_table_name);
const auto storage = DatabaseCatalog::instance().getTable(table_id, getContext());
if (storage->getName() != "Set")
return nullptr;
const auto storage_set = std::dynamic_pointer_cast<StorageSet>(storage);
return storage_set->getSet();
}
/// Performance optimization for IN() if storage supports it.
void SelectQueryExpressionAnalyzer::makeSetsForIndex(const ASTPtr & node)
{
if (!node || !storage() || !storage()->supportsIndexForIn())
return;
for (auto & child : node->children)
{
/// Don't descend into subqueries.
if (child->as<ASTSubquery>())
continue;
/// Don't descend into lambda functions
const auto * func = child->as<ASTFunction>();
if (func && func->name == "lambda")
continue;
makeSetsForIndex(child);
}
const auto * func = node->as<ASTFunction>();
if (func && functionIsInOrGlobalInOperator(func->name))
{
const IAST & args = *func->arguments;
const ASTPtr & left_in_operand = args.children.at(0);
if (storage()->mayBenefitFromIndexForIn(left_in_operand, getContext(), metadata_snapshot))
{
const ASTPtr & arg = args.children.at(1);
if (arg->as<ASTSubquery>() || arg->as<ASTTableIdentifier>())
{
if (settings.use_index_for_in_with_subqueries)
tryMakeSetForIndexFromSubquery(arg, query_options);
}
else
{
auto temp_actions = std::make_shared<ActionsDAG>(columns_after_join);
getRootActions(left_in_operand, true, temp_actions);
if (prepared_sets && temp_actions->tryFindInOutputs(left_in_operand->getColumnName()))
makeExplicitSet(func, *temp_actions, true, getContext(), settings.size_limits_for_set, *prepared_sets);
}
}
}
}
void ExpressionAnalyzer::getRootActions(const ASTPtr & ast, bool no_makeset_for_subqueries, ActionsDAGPtr & actions, bool only_consts)
{
LogAST log;
ActionsVisitor::Data visitor_data(
getContext(),
settings.size_limits_for_set,
subquery_depth,
sourceColumns(),
std::move(actions),
prepared_sets,
no_makeset_for_subqueries,
false /* no_makeset */,
only_consts,
!isRemoteStorage() /* create_source_for_in */,
getAggregationKeysInfo(),
false /* build_expression_with_window_functions */,
is_create_parameterized_view);
ActionsVisitor(visitor_data, log.stream()).visit(ast);
actions = visitor_data.getActions();
}
void ExpressionAnalyzer::getRootActionsNoMakeSet(const ASTPtr & ast, ActionsDAGPtr & actions, bool only_consts)
{
LogAST log;
ActionsVisitor::Data visitor_data(
getContext(),
settings.size_limits_for_set,
subquery_depth,
sourceColumns(),
std::move(actions),
prepared_sets,
true /* no_makeset_for_subqueries, no_makeset implies no_makeset_for_subqueries */,
true /* no_makeset */,
only_consts,
!isRemoteStorage() /* create_source_for_in */,
getAggregationKeysInfo(),
false /* build_expression_with_window_functions */,
is_create_parameterized_view);
ActionsVisitor(visitor_data, log.stream()).visit(ast);
actions = visitor_data.getActions();
}
void ExpressionAnalyzer::getRootActionsForHaving(
const ASTPtr & ast, bool no_makeset_for_subqueries, ActionsDAGPtr & actions, bool only_consts)
{
LogAST log;
ActionsVisitor::Data visitor_data(
getContext(),
settings.size_limits_for_set,
subquery_depth,
sourceColumns(),
std::move(actions),
prepared_sets,
no_makeset_for_subqueries,
false /* no_makeset */,
only_consts,
true /* create_source_for_in */,
getAggregationKeysInfo(),
false /* build_expression_with_window_functions */,
is_create_parameterized_view);
ActionsVisitor(visitor_data, log.stream()).visit(ast);
actions = visitor_data.getActions();
}
void ExpressionAnalyzer::getRootActionsForWindowFunctions(const ASTPtr & ast, bool no_makeset_for_subqueries, ActionsDAGPtr & actions)
{
LogAST log;
ActionsVisitor::Data visitor_data(
getContext(),
settings.size_limits_for_set,
subquery_depth,
sourceColumns(),
std::move(actions),
prepared_sets,
no_makeset_for_subqueries,
false /* no_makeset */,
false /*only_consts */,
!isRemoteStorage() /* create_source_for_in */,
getAggregationKeysInfo(),
true);
ActionsVisitor(visitor_data, log.stream()).visit(ast);
actions = visitor_data.getActions();
}
void ExpressionAnalyzer::makeAggregateDescriptions(ActionsDAGPtr & actions, AggregateDescriptions & descriptions)
{
for (const ASTFunction * node : aggregates())
{
AggregateDescription aggregate;
if (node->arguments)
getRootActionsNoMakeSet(node->arguments, actions);
aggregate.column_name = node->getColumnName();
const ASTs & arguments = node->arguments ? node->arguments->children : ASTs();
aggregate.argument_names.resize(arguments.size());
DataTypes types(arguments.size());
for (size_t i = 0; i < arguments.size(); ++i)
{
const std::string & name = arguments[i]->getColumnName();
const auto * dag_node = actions->tryFindInOutputs(name);
if (!dag_node)
{
throw Exception(ErrorCodes::UNKNOWN_IDENTIFIER,
"Unknown identifier '{}' in aggregate function '{}'",
name, node->formatForErrorMessage());
}
types[i] = dag_node->result_type;
aggregate.argument_names[i] = name;
}
AggregateFunctionProperties properties;
aggregate.parameters = (node->parameters) ? getAggregateFunctionParametersArray(node->parameters, "", getContext()) : Array();
aggregate.function = AggregateFunctionFactory::instance().get(node->name, types, aggregate.parameters, properties);
descriptions.push_back(aggregate);
}
}
void ExpressionAnalyzer::makeWindowDescriptionFromAST(const Context & context_,
const WindowDescriptions & existing_descriptions,
WindowDescription & desc, const IAST * ast)
{
const auto & definition = ast->as<const ASTWindowDefinition &>();
if (!definition.parent_window_name.empty())
{
auto it = existing_descriptions.find(definition.parent_window_name);
if (it == existing_descriptions.end())
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Window definition '{}' references an unknown window '{}'",
definition.formatForErrorMessage(),
definition.parent_window_name);
}
const auto & parent = it->second;
desc.partition_by = parent.partition_by;
desc.order_by = parent.order_by;
desc.frame = parent.frame;
// If an existing_window_name is specified it must refer to an earlier
// entry in the WINDOW list; the new window copies its partitioning clause
// from that entry, as well as its ordering clause if any. In this case
// the new window cannot specify its own PARTITION BY clause, and it can
// specify ORDER BY only if the copied window does not have one. The new
// window always uses its own frame clause; the copied window must not
// specify a frame clause.
// -- https://www.postgresql.org/docs/current/sql-select.html
if (definition.partition_by)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Derived window definition '{}' is not allowed to override PARTITION BY",
definition.formatForErrorMessage());
}
if (definition.order_by && !parent.order_by.empty())
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Derived window definition '{}' is not allowed to override a non-empty ORDER BY",
definition.formatForErrorMessage());
}
if (!parent.frame.is_default)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Parent window '{}' is not allowed to define a frame: while processing derived window definition '{}'",
definition.parent_window_name,
definition.formatForErrorMessage());
}
}
if (definition.partition_by)
{
for (const auto & column_ast : definition.partition_by->children)
{
const auto * with_alias = dynamic_cast<const ASTWithAlias *>(
column_ast.get());
if (!with_alias)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Expected a column in PARTITION BY in window definition,"
" got '{}'",
column_ast->formatForErrorMessage());
}
desc.partition_by.push_back(SortColumnDescription(
with_alias->getColumnName(), 1 /* direction */,
1 /* nulls_direction */));
auto actions_dag = std::make_shared<ActionsDAG>(aggregated_columns);
getRootActions(column_ast, false, actions_dag);
desc.partition_by_actions.push_back(std::move(actions_dag));
}
}
if (definition.order_by)
{
for (const auto & column_ast
: definition.order_by->children)
{
// Parser should have checked that we have a proper element here.
const auto & order_by_element
= column_ast->as<ASTOrderByElement &>();
// Ignore collation for now.
desc.order_by.push_back(
SortColumnDescription(
order_by_element.children.front()->getColumnName(),
order_by_element.direction,
order_by_element.nulls_direction));
auto actions_dag = std::make_shared<ActionsDAG>(aggregated_columns);
getRootActions(column_ast, false, actions_dag);
desc.order_by_actions.push_back(std::move(actions_dag));
}
}
desc.full_sort_description = desc.partition_by;
desc.full_sort_description.insert(desc.full_sort_description.end(),
desc.order_by.begin(), desc.order_by.end());
if (definition.frame_type != WindowFrame::FrameType::ROWS
&& definition.frame_type != WindowFrame::FrameType::RANGE)
{
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Window frame '{}' is not implemented (while processing '{}')",
definition.frame_type,
ast->formatForErrorMessage());
}
desc.frame.is_default = definition.frame_is_default;
desc.frame.type = definition.frame_type;
desc.frame.begin_type = definition.frame_begin_type;
desc.frame.begin_preceding = definition.frame_begin_preceding;
desc.frame.end_type = definition.frame_end_type;
desc.frame.end_preceding = definition.frame_end_preceding;
if (definition.frame_end_type == WindowFrame::BoundaryType::Offset)
{
auto [value, _] = evaluateConstantExpression(definition.frame_end_offset,
context_.shared_from_this());
desc.frame.end_offset = value;
}
if (definition.frame_begin_type == WindowFrame::BoundaryType::Offset)
{
auto [value, _] = evaluateConstantExpression(definition.frame_begin_offset,
context_.shared_from_this());
desc.frame.begin_offset = value;
}
}
void ExpressionAnalyzer::makeWindowDescriptions(ActionsDAGPtr actions)
{
auto current_context = getContext();
// Window definitions from the WINDOW clause
const auto * select_query = query->as<ASTSelectQuery>();
if (select_query && select_query->window())
{
for (const auto & ptr : select_query->window()->children)
{
const auto & elem = ptr->as<const ASTWindowListElement &>();
WindowDescription desc;
desc.window_name = elem.name;
makeWindowDescriptionFromAST(*current_context, window_descriptions,
desc, elem.definition.get());
auto [it, inserted] = window_descriptions.insert(
{desc.window_name, desc});
if (!inserted)
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"Window '{}' is defined twice in the WINDOW clause",
desc.window_name);
}
}
}
// Window functions
for (const ASTFunction * function_node : syntax->window_function_asts)
{
assert(function_node->is_window_function);
WindowFunctionDescription window_function;
window_function.function_node = function_node;
window_function.column_name
= window_function.function_node->getColumnName();
window_function.function_parameters
= window_function.function_node->parameters
? getAggregateFunctionParametersArray(
window_function.function_node->parameters, "", getContext())
: Array();
// Requiring a constant reference to a shared pointer to non-const AST
// doesn't really look sane, but the visitor does indeed require it.
// Hence we clone the node (not very sane either, I know).
getRootActionsNoMakeSet(window_function.function_node->clone(), actions);
const ASTs & arguments
= window_function.function_node->arguments->children;
window_function.argument_types.resize(arguments.size());
window_function.argument_names.resize(arguments.size());
for (size_t i = 0; i < arguments.size(); ++i)
{
const std::string & name = arguments[i]->getColumnName();
const auto * node = actions->tryFindInOutputs(name);
if (!node)
{
throw Exception(ErrorCodes::UNKNOWN_IDENTIFIER,
"Unknown identifier '{}' in window function '{}'",
name, window_function.function_node->formatForErrorMessage());
}
window_function.argument_types[i] = node->result_type;
window_function.argument_names[i] = name;
}
AggregateFunctionProperties properties;
window_function.aggregate_function
= AggregateFunctionFactory::instance().get(
window_function.function_node->name,
window_function.argument_types,
window_function.function_parameters, properties);
// Find the window corresponding to this function. It may be either
// referenced by name and previously defined in WINDOW clause, or it
// may be defined inline.
if (!function_node->window_name.empty())
{
auto it = window_descriptions.find(function_node->window_name);
if (it == std::end(window_descriptions))
{
throw Exception(ErrorCodes::UNKNOWN_IDENTIFIER,
"Window '{}' is not defined (referenced by '{}')",
function_node->window_name,
function_node->formatForErrorMessage());
}
it->second.window_functions.push_back(window_function);
}
else
{
const auto & definition = function_node->window_definition->as<
const ASTWindowDefinition &>();
WindowDescription desc;
desc.window_name = definition.getDefaultWindowName();
makeWindowDescriptionFromAST(*current_context, window_descriptions,
desc, &definition);
auto [it, inserted] = window_descriptions.insert(
{desc.window_name, desc});
if (!inserted)
{
assert(it->second.full_sort_description
== desc.full_sort_description);
}
it->second.window_functions.push_back(window_function);
}
}
bool compile_sort_description = current_context->getSettingsRef().compile_sort_description;
size_t min_count_to_compile_sort_description = current_context->getSettingsRef().min_count_to_compile_sort_description;
for (auto & [_, window_description] : window_descriptions)
{
window_description.full_sort_description.compile_sort_description = compile_sort_description;
window_description.full_sort_description.min_count_to_compile_sort_description = min_count_to_compile_sort_description;
window_description.partition_by.compile_sort_description = compile_sort_description;
window_description.partition_by.min_count_to_compile_sort_description = min_count_to_compile_sort_description;
}
}
const ASTSelectQuery * ExpressionAnalyzer::getSelectQuery() const
{
const auto * select_query = query->as<ASTSelectQuery>();
if (!select_query)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Not a select query");
return select_query;
}
const ASTSelectQuery * SelectQueryExpressionAnalyzer::getAggregatingQuery() const
{
if (!has_aggregation)
throw Exception(ErrorCodes::LOGICAL_ERROR, "No aggregation");
return getSelectQuery();
}
/// "Big" ARRAY JOIN.
ArrayJoinActionPtr ExpressionAnalyzer::addMultipleArrayJoinAction(ActionsDAGPtr & actions, bool array_join_is_left) const
{
NameSet result_columns;
for (const auto & result_source : syntax->array_join_result_to_source)
{
/// Assign new names to columns, if needed.
if (result_source.first != result_source.second)
{
const auto & node = actions->findInOutputs(result_source.second);
actions->getOutputs().push_back(&actions->addAlias(node, result_source.first));
}
/// Make ARRAY JOIN (replace arrays with their insides) for the columns in these new names.
result_columns.insert(result_source.first);
}
return std::make_shared<ArrayJoinAction>(result_columns, array_join_is_left, getContext());
}
ArrayJoinActionPtr SelectQueryExpressionAnalyzer::appendArrayJoin(ExpressionActionsChain & chain, ActionsDAGPtr & before_array_join, bool only_types)
{
const auto * select_query = getSelectQuery();
auto [array_join_expression_list, is_array_join_left] = select_query->arrayJoinExpressionList();
if (!array_join_expression_list)
return nullptr;
ExpressionActionsChain::Step & step = chain.lastStep(sourceColumns());
getRootActions(array_join_expression_list, only_types, step.actions());
auto array_join = addMultipleArrayJoinAction(step.actions(), is_array_join_left);
before_array_join = chain.getLastActions();
chain.steps.push_back(std::make_unique<ExpressionActionsChain::ArrayJoinStep>(array_join, step.getResultColumns()));
chain.addStep();
return array_join;
}
bool SelectQueryExpressionAnalyzer::appendJoinLeftKeys(ExpressionActionsChain & chain, bool only_types)
{
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_array_join);
getRootActions(analyzedJoin().leftKeysList(), only_types, step.actions());
return true;
}
JoinPtr SelectQueryExpressionAnalyzer::appendJoin(
ExpressionActionsChain & chain,
ActionsDAGPtr & converting_join_columns)
{
const ColumnsWithTypeAndName & left_sample_columns = chain.getLastStep().getResultColumns();
JoinPtr join = makeJoin(*syntax->ast_join, left_sample_columns, converting_join_columns);
if (converting_join_columns)
{
chain.steps.push_back(std::make_unique<ExpressionActionsChain::ExpressionActionsStep>(converting_join_columns));
chain.addStep();
}
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_array_join);
chain.steps.push_back(std::make_unique<ExpressionActionsChain::JoinStep>(
syntax->analyzed_join, join, step.getResultColumns()));
chain.addStep();
return join;
}
static ActionsDAGPtr createJoinedBlockActions(ContextPtr context, const TableJoin & analyzed_join)
{
ASTPtr expression_list = analyzed_join.rightKeysList();
auto syntax_result = TreeRewriter(context).analyze(expression_list, analyzed_join.columnsFromJoinedTable());
return ExpressionAnalyzer(expression_list, syntax_result, context).getActionsDAG(true, false);
}
std::shared_ptr<DirectKeyValueJoin> tryKeyValueJoin(std::shared_ptr<TableJoin> analyzed_join, const Block & right_sample_block);
static std::shared_ptr<IJoin> chooseJoinAlgorithm(
std::shared_ptr<TableJoin> analyzed_join, const ColumnsWithTypeAndName & left_sample_columns, std::unique_ptr<QueryPlan> & joined_plan, ContextPtr context)
{
const auto & settings = context->getSettings();
Block left_sample_block(left_sample_columns);
for (auto & column : left_sample_block)
{
if (!column.column)
column.column = column.type->createColumn();
}
Block right_sample_block = joined_plan->getCurrentDataStream().header;
std::vector<String> tried_algorithms;
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::DIRECT))
{
tried_algorithms.push_back(toString(JoinAlgorithm::DIRECT));
JoinPtr direct_join = tryKeyValueJoin(analyzed_join, right_sample_block);
if (direct_join)
{
/// Do not need to execute plan for right part, it's ready.
joined_plan.reset();
return direct_join;
}
}
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::PARTIAL_MERGE) ||
analyzed_join->isEnabledAlgorithm(JoinAlgorithm::PREFER_PARTIAL_MERGE))
{
tried_algorithms.push_back(toString(JoinAlgorithm::PARTIAL_MERGE));
if (MergeJoin::isSupported(analyzed_join))
return std::make_shared<MergeJoin>(analyzed_join, right_sample_block);
}
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::HASH) ||
/// partial_merge is preferred, but can't be used for specified kind of join, fallback to hash
analyzed_join->isEnabledAlgorithm(JoinAlgorithm::PREFER_PARTIAL_MERGE) ||
analyzed_join->isEnabledAlgorithm(JoinAlgorithm::PARALLEL_HASH))
{
tried_algorithms.push_back(toString(JoinAlgorithm::HASH));
if (analyzed_join->allowParallelHashJoin())
return std::make_shared<ConcurrentHashJoin>(context, analyzed_join, settings.max_threads, right_sample_block);
return std::make_shared<HashJoin>(analyzed_join, right_sample_block);
}
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::FULL_SORTING_MERGE))
{
tried_algorithms.push_back(toString(JoinAlgorithm::FULL_SORTING_MERGE));
if (FullSortingMergeJoin::isSupported(analyzed_join))
return std::make_shared<FullSortingMergeJoin>(analyzed_join, right_sample_block);
}
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::GRACE_HASH))
{
tried_algorithms.push_back(toString(JoinAlgorithm::GRACE_HASH));
if (GraceHashJoin::isSupported(analyzed_join))
return std::make_shared<GraceHashJoin>(context, analyzed_join, left_sample_block, right_sample_block, context->getTempDataOnDisk());
}
if (analyzed_join->isEnabledAlgorithm(JoinAlgorithm::AUTO))
{
tried_algorithms.push_back(toString(JoinAlgorithm::AUTO));
if (MergeJoin::isSupported(analyzed_join))
return std::make_shared<JoinSwitcher>(analyzed_join, right_sample_block);
return std::make_shared<HashJoin>(analyzed_join, right_sample_block);
}
throw Exception(ErrorCodes::NOT_IMPLEMENTED,
"Can't execute {} join algorithm for this strictness/kind and right storage type",
fmt::join(tried_algorithms, " or "));
}
static std::unique_ptr<QueryPlan> buildJoinedPlan(
ContextPtr context,
const ASTTablesInSelectQueryElement & join_element,
TableJoin & analyzed_join,
SelectQueryOptions query_options)
{
/// Actions which need to be calculated on joined block.
auto joined_block_actions = createJoinedBlockActions(context, analyzed_join);
NamesWithAliases required_columns_with_aliases = analyzed_join.getRequiredColumns(
Block(joined_block_actions->getResultColumns()), joined_block_actions->getRequiredColumns().getNames());
Names original_right_column_names;
for (auto & pr : required_columns_with_aliases)
original_right_column_names.push_back(pr.first);
/** For GLOBAL JOINs (in the case, for example, of the push method for executing GLOBAL subqueries), the following occurs
* - in the addExternalStorage function, the JOIN (SELECT ...) subquery is replaced with JOIN _data1,
* in the subquery_for_set object this subquery is exposed as source and the temporary table _data1 as the `table`.
* - this function shows the expression JOIN _data1.
* - JOIN tables will need aliases to correctly resolve USING clause.
*/
auto interpreter = interpretSubquery(
join_element.table_expression,
context,
original_right_column_names,
query_options.copy().setWithAllColumns().ignoreProjections(false).ignoreAlias(false));
auto joined_plan = std::make_unique<QueryPlan>();
interpreter->buildQueryPlan(*joined_plan);
{
Block original_right_columns = interpreter->getSampleBlock();
auto rename_dag = std::make_unique<ActionsDAG>(original_right_columns.getColumnsWithTypeAndName());
for (const auto & name_with_alias : required_columns_with_aliases)
{
if (name_with_alias.first != name_with_alias.second && original_right_columns.has(name_with_alias.first))
{
auto pos = original_right_columns.getPositionByName(name_with_alias.first);
const auto & alias = rename_dag->addAlias(*rename_dag->getInputs()[pos], name_with_alias.second);
rename_dag->getOutputs()[pos] = &alias;
}
}
rename_dag->projectInput();
auto rename_step = std::make_unique<ExpressionStep>(joined_plan->getCurrentDataStream(), std::move(rename_dag));
rename_step->setStepDescription("Rename joined columns");
joined_plan->addStep(std::move(rename_step));
}
auto joined_actions_step = std::make_unique<ExpressionStep>(joined_plan->getCurrentDataStream(), std::move(joined_block_actions));
joined_actions_step->setStepDescription("Joined actions");
joined_plan->addStep(std::move(joined_actions_step));
return joined_plan;
}
std::shared_ptr<DirectKeyValueJoin> tryKeyValueJoin(std::shared_ptr<TableJoin> analyzed_join, const Block & right_sample_block)
{
if (!analyzed_join->isEnabledAlgorithm(JoinAlgorithm::DIRECT))
return nullptr;
auto storage = analyzed_join->getStorageKeyValue();
if (!storage)
return nullptr;
bool allowed_inner = isInner(analyzed_join->kind()) && analyzed_join->strictness() == JoinStrictness::All;
bool allowed_left = isLeft(analyzed_join->kind()) && (analyzed_join->strictness() == JoinStrictness::Any ||
analyzed_join->strictness() == JoinStrictness::All ||
analyzed_join->strictness() == JoinStrictness::Semi ||
analyzed_join->strictness() == JoinStrictness::Anti);
if (!allowed_inner && !allowed_left)
{
LOG_TRACE(getLogger(), "Can't use direct join: {} {} is not supported",
analyzed_join->kind(), analyzed_join->strictness());
return nullptr;
}
const auto & clauses = analyzed_join->getClauses();
bool only_one_key = clauses.size() == 1 &&
clauses[0].key_names_left.size() == 1 &&
clauses[0].key_names_right.size() == 1 &&
!clauses[0].on_filter_condition_left &&
!clauses[0].on_filter_condition_right;
if (!only_one_key)
{
LOG_TRACE(getLogger(), "Can't use direct join: only one key is supported");
return nullptr;
}
String key_name = clauses[0].key_names_right[0];
String original_key_name = analyzed_join->getOriginalName(key_name);
const auto & storage_primary_key = storage->getPrimaryKey();
if (storage_primary_key.size() != 1 || storage_primary_key[0] != original_key_name)
{
LOG_TRACE(getLogger(), "Can't use direct join: join key '{}' doesn't match to storage key ({})",
original_key_name, fmt::join(storage_primary_key, ", "));
return nullptr;
}
return std::make_shared<DirectKeyValueJoin>(analyzed_join, right_sample_block, storage);
}
JoinPtr SelectQueryExpressionAnalyzer::makeJoin(
const ASTTablesInSelectQueryElement & join_element,
const ColumnsWithTypeAndName & left_columns,
ActionsDAGPtr & left_convert_actions)
{
/// Two JOINs are not supported with the same subquery, but different USINGs.
if (joined_plan)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Table join was already created for query");
ActionsDAGPtr right_convert_actions = nullptr;
const auto & analyzed_join = syntax->analyzed_join;
if (auto storage = analyzed_join->getStorageJoin())
{
auto right_columns = storage->getRightSampleBlock().getColumnsWithTypeAndName();
std::tie(left_convert_actions, right_convert_actions) = analyzed_join->createConvertingActions(left_columns, right_columns);
return storage->getJoinLocked(analyzed_join, getContext());
}
joined_plan = buildJoinedPlan(getContext(), join_element, *analyzed_join, query_options);
const ColumnsWithTypeAndName & right_columns = joined_plan->getCurrentDataStream().header.getColumnsWithTypeAndName();
std::tie(left_convert_actions, right_convert_actions) = analyzed_join->createConvertingActions(left_columns, right_columns);
if (right_convert_actions)
{
auto converting_step = std::make_unique<ExpressionStep>(joined_plan->getCurrentDataStream(), right_convert_actions);
converting_step->setStepDescription("Convert joined columns");
joined_plan->addStep(std::move(converting_step));
}
JoinPtr join = chooseJoinAlgorithm(analyzed_join, left_columns, joined_plan, getContext());
return join;
}
ActionsDAGPtr SelectQueryExpressionAnalyzer::appendPrewhere(
ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getSelectQuery();
if (!select_query->prewhere())
return nullptr;
Names first_action_names;
if (!chain.steps.empty())
first_action_names = chain.steps.front()->getRequiredColumns().getNames();
auto & step = chain.lastStep(sourceColumns());
getRootActions(select_query->prewhere(), only_types, step.actions());
String prewhere_column_name = select_query->prewhere()->getColumnName();
step.addRequiredOutput(prewhere_column_name);
const auto & node = step.actions()->findInOutputs(prewhere_column_name);
auto filter_type = node.result_type;
if (!filter_type->canBeUsedInBooleanContext())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_COLUMN_FOR_FILTER, "Invalid type for filter in PREWHERE: {}",
filter_type->getName());
ActionsDAGPtr prewhere_actions;
{
/// Remove unused source_columns from prewhere actions.
auto tmp_actions_dag = std::make_shared<ActionsDAG>(sourceColumns());
getRootActions(select_query->prewhere(), only_types, tmp_actions_dag);
/// Constants cannot be removed since they can be used in other parts of the query.
/// And if they are not used anywhere, except PREWHERE, they will be removed on the next step.
tmp_actions_dag->removeUnusedActions(
NameSet{prewhere_column_name},
/* allow_remove_inputs= */ true,
/* allow_constant_folding= */ false);
auto required_columns = tmp_actions_dag->getRequiredColumnsNames();
NameSet required_source_columns(required_columns.begin(), required_columns.end());
required_source_columns.insert(first_action_names.begin(), first_action_names.end());
auto names = step.actions()->getNames();
NameSet name_set(names.begin(), names.end());
for (const auto & column : sourceColumns())
if (!required_source_columns.contains(column.name))
name_set.erase(column.name);
Names required_output(name_set.begin(), name_set.end());
prewhere_actions = chain.getLastActions();
prewhere_actions->removeUnusedActions(required_output);
}
{
/// Add empty action with input = {prewhere actions output} + {unused source columns}
/// Reasons:
/// 1. Remove remove source columns which are used only in prewhere actions during prewhere actions execution.
/// Example: select A prewhere B > 0. B can be removed at prewhere step.
/// 2. Store side columns which were calculated during prewhere actions execution if they are used.
/// Example: select F(A) prewhere F(A) > 0. F(A) can be saved from prewhere step.
/// 3. Check if we can remove filter column at prewhere step. If we can, action will store single REMOVE_COLUMN.
ColumnsWithTypeAndName columns = prewhere_actions->getResultColumns();
auto required_columns = prewhere_actions->getRequiredColumns();
NameSet prewhere_input_names;
NameSet unused_source_columns;
for (const auto & col : required_columns)
prewhere_input_names.insert(col.name);
for (const auto & column : sourceColumns())
{
if (!prewhere_input_names.contains(column.name))
{
columns.emplace_back(column.type, column.name);
unused_source_columns.emplace(column.name);
}
}
chain.steps.emplace_back(
std::make_unique<ExpressionActionsChain::ExpressionActionsStep>(std::make_shared<ActionsDAG>(std::move(columns))));
chain.steps.back()->additional_input = std::move(unused_source_columns);
chain.getLastActions();
chain.addStep();
}
return prewhere_actions;
}
bool SelectQueryExpressionAnalyzer::appendWhere(ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getSelectQuery();
if (!select_query->where())
return false;
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_join);
getRootActions(select_query->where(), only_types, step.actions());
auto where_column_name = select_query->where()->getColumnName();
step.addRequiredOutput(where_column_name);
const auto & node = step.actions()->findInOutputs(where_column_name);
auto filter_type = node.result_type;
if (!filter_type->canBeUsedInBooleanContext())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_COLUMN_FOR_FILTER, "Invalid type for filter in WHERE: {}",
filter_type->getName());
return true;
}
bool SelectQueryExpressionAnalyzer::appendGroupBy(ExpressionActionsChain & chain, bool only_types, bool optimize_aggregation_in_order,
ManyExpressionActions & group_by_elements_actions)
{
const auto * select_query = getAggregatingQuery();
if (!select_query->groupBy())
return false;
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_join);
ASTs asts = select_query->groupBy()->children;
if (select_query->group_by_with_grouping_sets)
{
for (const auto & ast : asts)
{
for (const auto & ast_element : ast->children)
{
step.addRequiredOutput(ast_element->getColumnName());
getRootActions(ast_element, only_types, step.actions());
}
}
}
else
{
for (const auto & ast : asts)
{
step.addRequiredOutput(ast->getColumnName());
getRootActions(ast, only_types, step.actions());
}
}
if (optimize_aggregation_in_order)
{
for (auto & child : asts)
{
auto actions_dag = std::make_shared<ActionsDAG>(columns_after_join);
getRootActions(child, only_types, actions_dag);
group_by_elements_actions.emplace_back(
std::make_shared<ExpressionActions>(actions_dag, ExpressionActionsSettings::fromContext(getContext(), CompileExpressions::yes)));
}
}
return true;
}
void SelectQueryExpressionAnalyzer::appendAggregateFunctionsArguments(ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getAggregatingQuery();
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_join);
for (const auto & desc : aggregate_descriptions)
for (const auto & name : desc.argument_names)
step.addRequiredOutput(name);
/// Collect aggregates removing duplicates by node.getColumnName()
/// It's not clear why we recollect aggregates (for query parts) while we're able to use previously collected ones (for entire query)
/// @note The original recollection logic didn't remove duplicates.
GetAggregatesVisitor::Data data;
GetAggregatesVisitor(data).visit(select_query->select());
if (select_query->having())
GetAggregatesVisitor(data).visit(select_query->having());
if (select_query->orderBy())
GetAggregatesVisitor(data).visit(select_query->orderBy());
/// TODO: data.aggregates -> aggregates()
for (const ASTFunction * node : data.aggregates)
if (node->arguments)
for (auto & argument : node->arguments->children)
getRootActions(argument, only_types, step.actions());
}
void SelectQueryExpressionAnalyzer::appendWindowFunctionsArguments(
ExpressionActionsChain & chain, bool /* only_types */)
{
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
// (1) Add actions for window functions and the columns they require.
// (2) Mark the columns that are really required. We have to mark them as
// required because we finish the expression chain before processing the
// window functions.
// The required columns are:
// (a) window function arguments,
// (b) the columns from PARTITION BY and ORDER BY.
// (1a) Actions for PARTITION BY and ORDER BY for windows defined in the
// WINDOW clause. The inline window definitions will be processed
// recursively together with (1b) as ASTFunction::window_definition.
if (getSelectQuery()->window())
{
getRootActionsNoMakeSet(getSelectQuery()->window(), step.actions());
}
for (const auto & [_, w] : window_descriptions)
{
for (const auto & f : w.window_functions)
{
// (1b) Actions for function arguments, and also the inline window
// definitions (1a).
// Requiring a constant reference to a shared pointer to non-const AST
// doesn't really look sane, but the visitor does indeed require it.
getRootActionsNoMakeSet(f.function_node->clone(), step.actions());
// (2b) Required function argument columns.
for (const auto & a : f.function_node->arguments->children)
{
step.addRequiredOutput(a->getColumnName());
}
}
// (2a) Required PARTITION BY and ORDER BY columns.
for (const auto & c : w.full_sort_description)
{
step.addRequiredOutput(c.column_name);
}
}
}
void SelectQueryExpressionAnalyzer::appendExpressionsAfterWindowFunctions(ExpressionActionsChain & chain, bool /* only_types */)
{
ExpressionActionsChain::Step & step = chain.lastStep(columns_after_window);
for (const auto & expression : syntax->expressions_with_window_function)
{
getRootActionsForWindowFunctions(expression->clone(), true, step.actions());
}
}
void SelectQueryExpressionAnalyzer::appendGroupByModifiers(ActionsDAGPtr & before_aggregation, ExpressionActionsChain & chain, bool /* only_types */)
{
const auto * select_query = getAggregatingQuery();
if (!select_query->groupBy() || !(select_query->group_by_with_rollup || select_query->group_by_with_cube))
return;
auto source_columns = before_aggregation->getResultColumns();
ColumnsWithTypeAndName result_columns;
for (const auto & source_column : source_columns)
{
if (source_column.type->canBeInsideNullable())
result_columns.emplace_back(makeNullableSafe(source_column.type), source_column.name);
else
result_columns.push_back(source_column);
}
ExpressionActionsChain::Step & step = chain.lastStep(before_aggregation->getNamesAndTypesList());
step.actions() = ActionsDAG::makeConvertingActions(source_columns, result_columns, ActionsDAG::MatchColumnsMode::Position);
}
void SelectQueryExpressionAnalyzer::appendSelectSkipWindowExpressions(ExpressionActionsChain::Step & step, ASTPtr const & node)
{
if (auto * function = node->as<ASTFunction>())
{
// Skip window function columns here -- they are calculated after
// other SELECT expressions by a special step.
// Also skipping lambda functions because they can't be explicitly evaluated.
if (function->is_window_function || function->name == "lambda")
return;
if (function->compute_after_window_functions)
{
for (auto & arg : function->arguments->children)
appendSelectSkipWindowExpressions(step, arg);
return;
}
}
step.addRequiredOutput(node->getColumnName());
}
bool SelectQueryExpressionAnalyzer::appendHaving(ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getAggregatingQuery();
if (!select_query->having())
return false;
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
getRootActionsForHaving(select_query->having(), only_types, step.actions());
step.addRequiredOutput(select_query->having()->getColumnName());
return true;
}
void SelectQueryExpressionAnalyzer::appendSelect(ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getSelectQuery();
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
getRootActions(select_query->select(), only_types, step.actions());
for (const auto & child : select_query->select()->children)
appendSelectSkipWindowExpressions(step, child);
}
ActionsDAGPtr SelectQueryExpressionAnalyzer::appendOrderBy(ExpressionActionsChain & chain, bool only_types, bool optimize_read_in_order,
ManyExpressionActions & order_by_elements_actions)
{
const auto * select_query = getSelectQuery();
if (!select_query->orderBy())
{
auto actions = chain.getLastActions();
chain.addStep();
return actions;
}
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
for (auto & child : select_query->orderBy()->children)
{
auto * ast = child->as<ASTOrderByElement>();
if (!ast || ast->children.empty())
throw Exception(ErrorCodes::UNKNOWN_TYPE_OF_AST_NODE, "Bad ORDER BY expression AST");
if (getContext()->getSettingsRef().enable_positional_arguments)
replaceForPositionalArguments(ast->children.at(0), select_query, ASTSelectQuery::Expression::ORDER_BY);
}
getRootActions(select_query->orderBy(), only_types, step.actions());
bool with_fill = false;
for (auto & child : select_query->orderBy()->children)
{
auto * ast = child->as<ASTOrderByElement>();
ASTPtr order_expression = ast->children.at(0);
const String & column_name = order_expression->getColumnName();
step.addRequiredOutput(column_name);
order_by_keys.emplace(column_name);
if (ast->with_fill)
with_fill = true;
}
if (auto interpolate_list = select_query->interpolate())
{
NameSet select;
for (const auto & child : select_query->select()->children)
select.insert(child->getAliasOrColumnName());
/// collect columns required for interpolate expressions -
/// interpolate expression can use any available column
auto find_columns = [&step, &select](IAST * function)
{
auto f_impl = [&step, &select](IAST * fn, auto fi)
{
if (auto * ident = fn->as<ASTIdentifier>())
{
/// exclude columns from select expression - they are already available
if (!select.contains(ident->getColumnName()))
step.addRequiredOutput(ident->getColumnName());
return;
}
if (fn->as<ASTFunction>() || fn->as<ASTExpressionList>())
for (const auto & ch : fn->children)
fi(ch.get(), fi);
return;
};
f_impl(function, f_impl);
};
for (const auto & interpolate : interpolate_list->children)
find_columns(interpolate->as<ASTInterpolateElement>()->expr.get());
}
if (optimize_read_in_order)
{
for (const auto & child : select_query->orderBy()->children)
{
auto actions_dag = std::make_shared<ActionsDAG>(columns_after_join);
getRootActions(child, only_types, actions_dag);
order_by_elements_actions.emplace_back(
std::make_shared<ExpressionActions>(actions_dag, ExpressionActionsSettings::fromContext(getContext(), CompileExpressions::yes)));
}
}
NameSet non_constant_inputs;
if (with_fill)
{
for (const auto & column : step.getResultColumns())
non_constant_inputs.insert(column.name);
}
auto actions = chain.getLastActions();
chain.addStep(non_constant_inputs);
return actions;
}
bool SelectQueryExpressionAnalyzer::appendLimitBy(ExpressionActionsChain & chain, bool only_types)
{
const auto * select_query = getSelectQuery();
if (!select_query->limitBy())
return false;
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
getRootActions(select_query->limitBy(), only_types, step.actions());
NameSet existing_column_names;
for (const auto & column : aggregated_columns)
{
step.addRequiredOutput(column.name);
existing_column_names.insert(column.name);
}
/// Columns from ORDER BY could be required to do ORDER BY on the initiator in case of distributed queries.
for (const auto & column_name : order_by_keys)
{
step.addRequiredOutput(column_name);
existing_column_names.insert(column_name);
}
auto & children = select_query->limitBy()->children;
for (auto & child : children)
{
if (getContext()->getSettingsRef().enable_positional_arguments)
replaceForPositionalArguments(child, select_query, ASTSelectQuery::Expression::LIMIT_BY);
auto child_name = child->getColumnName();
if (!existing_column_names.contains(child_name))
step.addRequiredOutput(child_name);
}
return true;
}
ActionsDAGPtr SelectQueryExpressionAnalyzer::appendProjectResult(ExpressionActionsChain & chain) const
{
const auto * select_query = getSelectQuery();
ExpressionActionsChain::Step & step = chain.lastStep(aggregated_columns);
NamesWithAliases result_columns;
NameSet required_result_columns_set(required_result_columns.begin(), required_result_columns.end());
ASTs asts = select_query->select()->children;
for (const auto & ast : asts)
{
String result_name = ast->getAliasOrColumnName();
if (required_result_columns_set.empty() || required_result_columns_set.contains(result_name))
{
std::string source_name = ast->getColumnName();
/*
* For temporary columns created by ExpressionAnalyzer for literals,
* use the correct source column. Using the default display name
* returned by getColumnName is not enough, and we have to use the
* column id set by EA. In principle, this logic applies to all kinds
* of columns, not only literals. Literals are especially problematic
* for two reasons:
* 1) confusing different literal columns leads to weird side
* effects (see 01101_literal_columns_clash);
* 2) the disambiguation mechanism in SyntaxAnalyzer, that, among
* other things, creates unique aliases for columns with same
* names from different tables, is applied before these temporary
* columns are created by ExpressionAnalyzer.
* Similar problems should also manifest for function columns, which
* are likewise created at a later stage by EA.
* In general, we need to have explicit separation between display
* names and identifiers for columns. This code is a workaround for
* a particular subclass of problems, and not a proper solution.
*/
if (const auto * as_literal = ast->as<ASTLiteral>())
{
source_name = as_literal->unique_column_name;
assert(!source_name.empty());
}
result_columns.emplace_back(source_name, result_name);
step.addRequiredOutput(result_columns.back().second);
}
}
auto actions = chain.getLastActions();
actions->project(result_columns);
if (!required_result_columns.empty())
{
result_columns.clear();
for (const auto & column : required_result_columns)
result_columns.emplace_back(column, std::string{});
actions->project(result_columns);
}
return actions;
}
void ExpressionAnalyzer::appendExpression(ExpressionActionsChain & chain, const ASTPtr & expr, bool only_types)
{
ExpressionActionsChain::Step & step = chain.lastStep(sourceColumns());
getRootActions(expr, only_types, step.actions());
step.addRequiredOutput(expr->getColumnName());
}
ActionsDAGPtr ExpressionAnalyzer::getActionsDAG(bool add_aliases, bool project_result)
{
auto actions_dag = std::make_shared<ActionsDAG>(aggregated_columns);
NamesWithAliases result_columns;
Names result_names;
ASTs asts;
if (const auto * node = query->as<ASTExpressionList>())
asts = node->children;
else
asts = ASTs(1, query);
for (const auto & ast : asts)
{
std::string name = ast->getColumnName();
std::string alias;
if (add_aliases)
alias = ast->getAliasOrColumnName();
else
alias = name;
result_columns.emplace_back(name, alias);
result_names.push_back(alias);
getRootActions(ast, false /* no_makeset_for_subqueries */, actions_dag);
}
if (add_aliases)
{
if (project_result)
actions_dag->project(result_columns);
else
actions_dag->addAliases(result_columns);
}
if (!(add_aliases && project_result))
{
NameSet name_set(result_names.begin(), result_names.end());
/// We will not delete the original columns.
for (const auto & column_name_type : sourceColumns())
{
if (!name_set.contains(column_name_type.name))
{
result_names.push_back(column_name_type.name);
name_set.insert(column_name_type.name);
}
}
actions_dag->removeUnusedActions(name_set);
}
return actions_dag;
}
ExpressionActionsPtr ExpressionAnalyzer::getActions(bool add_aliases, bool project_result, CompileExpressions compile_expressions)
{
return std::make_shared<ExpressionActions>(
getActionsDAG(add_aliases, project_result), ExpressionActionsSettings::fromContext(getContext(), compile_expressions));
}
ActionsDAGPtr ExpressionAnalyzer::getConstActionsDAG(const ColumnsWithTypeAndName & constant_inputs)
{
auto actions = std::make_shared<ActionsDAG>(constant_inputs);
getRootActions(query, true /* no_makeset_for_subqueries */, actions, true /* only_consts */);
return actions;
}
ExpressionActionsPtr ExpressionAnalyzer::getConstActions(const ColumnsWithTypeAndName & constant_inputs)
{
auto actions = getConstActionsDAG(constant_inputs);
return std::make_shared<ExpressionActions>(actions, ExpressionActionsSettings::fromContext(getContext()));
}
std::unique_ptr<QueryPlan> SelectQueryExpressionAnalyzer::getJoinedPlan()
{
return std::move(joined_plan);
}
ActionsDAGPtr SelectQueryExpressionAnalyzer::simpleSelectActions()
{
ExpressionActionsChain new_chain(getContext());
appendSelect(new_chain, false);
return new_chain.getLastActions();
}
ExpressionAnalysisResult::ExpressionAnalysisResult(
SelectQueryExpressionAnalyzer & query_analyzer,
const StorageMetadataPtr & metadata_snapshot,
bool first_stage_,
bool second_stage_,
bool only_types,
const FilterDAGInfoPtr & filter_info_,
const FilterDAGInfoPtr & additional_filter,
const Block & source_header)
: first_stage(first_stage_)
, second_stage(second_stage_)
, need_aggregate(query_analyzer.hasAggregation())
, has_window(query_analyzer.hasWindow())
, use_grouping_set_key(query_analyzer.useGroupingSetKey())
{
/// first_stage: Do I need to perform the first part of the pipeline - running on remote servers during distributed processing.
/// second_stage: Do I need to execute the second part of the pipeline - running on the initiating server during distributed processing.
/** First we compose a chain of actions and remember the necessary steps from it.
* Regardless of from_stage and to_stage, we will compose a complete sequence of actions to perform optimization and
* throw out unnecessary columns based on the entire query. In unnecessary parts of the query, we will not execute subqueries.
*/
const ASTSelectQuery & query = *query_analyzer.getSelectQuery();
auto context = query_analyzer.getContext();
const Settings & settings = context->getSettingsRef();
const ConstStoragePtr & storage = query_analyzer.storage();
Names additional_required_columns_after_prewhere;
ssize_t prewhere_step_num = -1;
ssize_t where_step_num = -1;
ssize_t having_step_num = -1;
auto finalize_chain = [&](ExpressionActionsChain & chain) -> ColumnsWithTypeAndName
{
if (prewhere_step_num >= 0)
{
ExpressionActionsChain::Step & step = *chain.steps.at(prewhere_step_num);
auto required_columns = prewhere_info->prewhere_actions->getRequiredColumnsNames();
NameSet required_source_columns(required_columns.begin(), required_columns.end());
/// Add required columns to required output in order not to remove them after prewhere execution.
/// TODO: add sampling and final execution to common chain.
for (const auto & column : additional_required_columns_after_prewhere)
{
if (required_source_columns.contains(column))
step.addRequiredOutput(column);
}
}
chain.finalize();
finalize(chain, prewhere_step_num, where_step_num, having_step_num, query);
auto res = chain.getLastStep().getResultColumns();
chain.clear();
return res;
};
{
ExpressionActionsChain chain(context);
if (storage && (query.sampleSize() || settings.parallel_replicas_count > 1))
{
// we evaluate sampling for Merge lazily so we need to get all the columns
if (storage->getName() == "Merge")
{
const auto columns = metadata_snapshot->getColumns().getAll();
for (const auto & column : columns)
{
additional_required_columns_after_prewhere.push_back(column.name);
}
}
else
{
Names columns_for_sampling = metadata_snapshot->getColumnsRequiredForSampling();
additional_required_columns_after_prewhere.insert(additional_required_columns_after_prewhere.end(),
columns_for_sampling.begin(), columns_for_sampling.end());
}
}
if (storage && query.final())
{
Names columns_for_final = metadata_snapshot->getColumnsRequiredForFinal();
additional_required_columns_after_prewhere.insert(additional_required_columns_after_prewhere.end(),
columns_for_final.begin(), columns_for_final.end());
}
if (storage && additional_filter)
{
Names columns_for_additional_filter = additional_filter->actions->getRequiredColumnsNames();
additional_required_columns_after_prewhere.insert(additional_required_columns_after_prewhere.end(),
columns_for_additional_filter.begin(), columns_for_additional_filter.end());
}
if (storage && filter_info_)
{
filter_info = filter_info_;
filter_info->do_remove_column = true;
}
if (auto actions = query_analyzer.appendPrewhere(chain, !first_stage))
{
/// Prewhere is always the first one.
prewhere_step_num = 0;
prewhere_info = std::make_shared<PrewhereInfo>(actions, query.prewhere()->getColumnName());
if (allowEarlyConstantFolding(*prewhere_info->prewhere_actions, settings))
{
Block before_prewhere_sample = source_header;
if (sanitizeBlock(before_prewhere_sample))
{
ExpressionActions(
prewhere_info->prewhere_actions,
ExpressionActionsSettings::fromSettings(context->getSettingsRef())).execute(before_prewhere_sample);
auto & column_elem = before_prewhere_sample.getByName(query.prewhere()->getColumnName());
/// If the filter column is a constant, record it.
if (column_elem.column)
prewhere_constant_filter_description = ConstantFilterDescription(*column_elem.column);
}
}
}
array_join = query_analyzer.appendArrayJoin(chain, before_array_join, only_types || !first_stage);
if (query_analyzer.hasTableJoin())
{
query_analyzer.appendJoinLeftKeys(chain, only_types || !first_stage);
before_join = chain.getLastActions();
join = query_analyzer.appendJoin(chain, converting_join_columns);
chain.addStep();
}
if (query_analyzer.appendWhere(chain, only_types || !first_stage))
{
where_step_num = chain.steps.size() - 1;
before_where = chain.getLastActions();
if (allowEarlyConstantFolding(*before_where, settings))
{
Block before_where_sample;
if (chain.steps.size() > 1)
before_where_sample = Block(chain.steps[chain.steps.size() - 2]->getResultColumns());
else
before_where_sample = source_header;
if (sanitizeBlock(before_where_sample))
{
ExpressionActions(
before_where,
ExpressionActionsSettings::fromSettings(context->getSettingsRef())).execute(before_where_sample);
auto & column_elem
= before_where_sample.getByName(query.where()->getColumnName());
/// If the filter column is a constant, record it.
if (column_elem.column)
where_constant_filter_description = ConstantFilterDescription(*column_elem.column);
}
}
chain.addStep();
}
if (need_aggregate)
{
/// TODO correct conditions
optimize_aggregation_in_order =
context->getSettingsRef().optimize_aggregation_in_order
&& (!context->getSettingsRef().query_plan_aggregation_in_order)
&& storage && query.groupBy();
query_analyzer.appendGroupBy(chain, only_types || !first_stage, optimize_aggregation_in_order, group_by_elements_actions);
query_analyzer.appendAggregateFunctionsArguments(chain, only_types || !first_stage);
before_aggregation = chain.getLastActions();
if (settings.group_by_use_nulls)
query_analyzer.appendGroupByModifiers(before_aggregation, chain, only_types);
auto columns_before_aggregation = finalize_chain(chain);
/// Here we want to check that columns after aggregation have the same type as
/// were promised in query_analyzer.aggregated_columns
/// Ideally, they should be equal. In practice, this may be not true.
/// As an example, we don't build sets for IN inside ExpressionAnalysis::analyzeAggregation,
/// so that constant folding for expression (1 in 1) will not work. This may change the return type
/// for functions with LowCardinality argument: function "substr(toLowCardinality('abc'), 1 IN 1)"
/// should usually return LowCardinality(String) when (1 IN 1) is constant, but without built set
/// for (1 IN 1) constant is not propagated and "substr" returns String type.
/// See 02503_in_lc_const_args_bug.sql
///
/// As a temporary solution, we add converting actions to the next chain.
/// Hopefully, later we can
/// * use a new analyzer where this issue is absent
/// * or remove ExpressionActionsChain completely and re-implement its logic on top of the query plan
{
for (auto & col : columns_before_aggregation)
if (!col.column)
col.column = col.type->createColumn();
Block header_before_aggregation(std::move(columns_before_aggregation));
auto keys = query_analyzer.aggregationKeys().getNames();
const auto & aggregates = query_analyzer.aggregates();
bool has_grouping = query_analyzer.group_by_kind != GroupByKind::ORDINARY;
auto actual_header = Aggregator::Params::getHeader(
header_before_aggregation, /*only_merge*/ false, keys, aggregates, /*final*/ true);
actual_header = AggregatingStep::appendGroupingColumn(
std::move(actual_header), keys, has_grouping, settings.group_by_use_nulls);
Block expected_header;
for (const auto & expected : query_analyzer.aggregated_columns)
expected_header.insert(ColumnWithTypeAndName(expected.type, expected.name));
if (!blocksHaveEqualStructure(actual_header, expected_header))
{
auto converting = ActionsDAG::makeConvertingActions(
actual_header.getColumnsWithTypeAndName(),
expected_header.getColumnsWithTypeAndName(),
ActionsDAG::MatchColumnsMode::Name,
true);
auto & step = chain.lastStep(query_analyzer.aggregated_columns);
auto & actions = step.actions();
actions = ActionsDAG::merge(std::move(*actions), std::move(*converting));
}
}
if (query_analyzer.appendHaving(chain, only_types || !second_stage))
{
having_step_num = chain.steps.size() - 1;
before_having = chain.getLastActions();
chain.addStep();
}
}
bool join_allow_read_in_order = true;
if (hasJoin())
{
/// You may find it strange but we support read_in_order for HashJoin and do not support for MergeJoin.
join_has_delayed_stream = query_analyzer.analyzedJoin().needStreamWithNonJoinedRows();
join_allow_read_in_order = typeid_cast<HashJoin *>(join.get()) && !join_has_delayed_stream;
}
optimize_read_in_order =
settings.optimize_read_in_order && (!settings.query_plan_read_in_order)
&& storage
&& query.orderBy()
&& !query_analyzer.hasAggregation()
&& !query_analyzer.hasWindow()
&& !query.final()
&& join_allow_read_in_order;
/// If there is aggregation, we execute expressions in SELECT and ORDER BY on the initiating server, otherwise on the source servers.
query_analyzer.appendSelect(chain, only_types || (need_aggregate ? !second_stage : !first_stage));
// Window functions are processed in a separate expression chain after
// the main SELECT, similar to what we do for aggregate functions.
if (has_window)
{
query_analyzer.makeWindowDescriptions(chain.getLastActions());
query_analyzer.appendWindowFunctionsArguments(chain, only_types || !first_stage);
// Build a list of output columns of the window step.
// 1) We need the columns that are the output of ExpressionActions.
for (const auto & x : chain.getLastActions()->getNamesAndTypesList())
{
query_analyzer.columns_after_window.push_back(x);
}
// 2) We also have to manually add the output of the window function
// to the list of the output columns of the window step, because the
// window functions are not in the ExpressionActions.
for (const auto & [_, w] : query_analyzer.window_descriptions)
{
for (const auto & f : w.window_functions)
{
query_analyzer.columns_after_window.push_back(
{f.column_name, f.aggregate_function->getResultType()});
}
}
// Here we need to set order by expression as required output to avoid
// their removal from the ActionsDAG.
const auto * select_query = query_analyzer.getSelectQuery();
if (select_query->orderBy())
{
for (auto & child : select_query->orderBy()->children)
{
auto * ast = child->as<ASTOrderByElement>();
ASTPtr order_expression = ast->children.at(0);
if (auto * function = order_expression->as<ASTFunction>();
function && (function->is_window_function || function->compute_after_window_functions))
continue;
const String & column_name = order_expression->getColumnName();
chain.getLastStep().addRequiredOutput(column_name);
}
}
before_window = chain.getLastActions();
finalize_chain(chain);
query_analyzer.appendExpressionsAfterWindowFunctions(chain, only_types || !first_stage);
for (const auto & x : chain.getLastActions()->getNamesAndTypesList())
{
query_analyzer.columns_after_window.push_back(x);
}
auto & step = chain.lastStep(query_analyzer.columns_after_window);
// The output of this expression chain is the result of
// SELECT (before "final projection" i.e. renaming the columns), so
// we have to mark the expressions that are required in the output,
// again. We did it for the previous expression chain ("select without
// window functions") earlier, in appendSelect(). But that chain also
// produced the expressions required to calculate window functions.
// They are not needed in the final SELECT result. Knowing the correct
// list of columns is important when we apply SELECT DISTINCT later.
for (const auto & child : select_query->select()->children)
{
step.addRequiredOutput(child->getColumnName());
}
}
selected_columns.clear();
selected_columns.reserve(chain.getLastStep().required_output.size());
for (const auto & it : chain.getLastStep().required_output)
selected_columns.emplace_back(it.first);
has_order_by = query.orderBy() != nullptr;
before_order_by = query_analyzer.appendOrderBy(
chain,
only_types || (need_aggregate ? !second_stage : !first_stage),
optimize_read_in_order,
order_by_elements_actions);
if (query_analyzer.appendLimitBy(chain, only_types || !second_stage))
{
before_limit_by = chain.getLastActions();
chain.addStep();
}
final_projection = query_analyzer.appendProjectResult(chain);
finalize_chain(chain);
}
/// Before executing WHERE and HAVING, remove the extra columns from the block (mostly the aggregation keys).
removeExtraColumns();
checkActions();
}
void ExpressionAnalysisResult::finalize(
const ExpressionActionsChain & chain,
ssize_t & prewhere_step_num,
ssize_t & where_step_num,
ssize_t & having_step_num,
const ASTSelectQuery & query)
{
if (prewhere_step_num >= 0)
{
const ExpressionActionsChain::Step & step = *chain.steps.at(prewhere_step_num);
prewhere_info->prewhere_actions->projectInput(false);
NameSet columns_to_remove;
for (const auto & [name, can_remove] : step.required_output)
{
if (name == prewhere_info->prewhere_column_name)
prewhere_info->remove_prewhere_column = can_remove;
else if (can_remove)
columns_to_remove.insert(name);
}
columns_to_remove_after_prewhere = std::move(columns_to_remove);
prewhere_step_num = -1;
}
if (where_step_num >= 0)
{
where_column_name = query.where()->getColumnName();
remove_where_filter = chain.steps.at(where_step_num)->required_output.find(where_column_name)->second;
where_step_num = -1;
}
if (having_step_num >= 0)
{
having_column_name = query.having()->getColumnName();
remove_having_filter = chain.steps.at(having_step_num)->required_output.find(having_column_name)->second;
having_step_num = -1;
}
}
void ExpressionAnalysisResult::removeExtraColumns() const
{
if (hasWhere())
before_where->projectInput();
if (hasHaving())
before_having->projectInput();
}
void ExpressionAnalysisResult::checkActions() const
{
/// Check that PREWHERE doesn't contain unusual actions. Unusual actions are that can change number of rows.
if (hasPrewhere())
{
auto check_actions = [](const ActionsDAGPtr & actions)
{
if (actions)
for (const auto & node : actions->getNodes())
if (node.type == ActionsDAG::ActionType::ARRAY_JOIN)
throw Exception(ErrorCodes::ILLEGAL_PREWHERE, "PREWHERE cannot contain ARRAY JOIN action");
};
check_actions(prewhere_info->prewhere_actions);
}
}
std::string ExpressionAnalysisResult::dump() const
{
WriteBufferFromOwnString ss;
ss << "need_aggregate " << need_aggregate << "\n";
ss << "has_order_by " << has_order_by << "\n";
ss << "has_window " << has_window << "\n";
if (before_array_join)
{
ss << "before_array_join " << before_array_join->dumpDAG() << "\n";
}
if (array_join)
{
ss << "array_join " << "FIXME doesn't have dump" << "\n";
}
if (before_join)
{
ss << "before_join " << before_join->dumpDAG() << "\n";
}
if (before_where)
{
ss << "before_where " << before_where->dumpDAG() << "\n";
}
if (prewhere_info)
{
ss << "prewhere_info " << prewhere_info->dump() << "\n";
}
if (filter_info)
{
ss << "filter_info " << filter_info->dump() << "\n";
}
if (before_aggregation)
{
ss << "before_aggregation " << before_aggregation->dumpDAG() << "\n";
}
if (before_having)
{
ss << "before_having " << before_having->dumpDAG() << "\n";
}
if (before_window)
{
ss << "before_window " << before_window->dumpDAG() << "\n";
}
if (before_order_by)
{
ss << "before_order_by " << before_order_by->dumpDAG() << "\n";
}
if (before_limit_by)
{
ss << "before_limit_by " << before_limit_by->dumpDAG() << "\n";
}
if (final_projection)
{
ss << "final_projection " << final_projection->dumpDAG() << "\n";
}
if (!selected_columns.empty())
{
ss << "selected_columns ";
for (size_t i = 0; i < selected_columns.size(); ++i)
{
if (i > 0)
{
ss << ", ";
}
ss << backQuote(selected_columns[i]);
}
ss << "\n";
}
return ss.str();
}
}