提交 d61c53fc 编写于 作者: Z zhang2014

ISSUES-863 support predicate push down with subquery

上级 7893d584
......@@ -28,6 +28,7 @@
#include <Interpreters/ExpressionActions.h>
#include <Interpreters/InJoinSubqueriesPreprocessor.h>
#include <Interpreters/LogicalExpressionsOptimizer.h>
#include <Interpreters/PredicateExpressionsOptimizer.h>
#include <Interpreters/ExternalDictionaries.h>
#include <Interpreters/convertFieldToType.h>
#include <Interpreters/Set.h>
......@@ -241,6 +242,9 @@ ExpressionAnalyzer::ExpressionAnalyzer(
/// array_join_alias_to_name, array_join_result_to_source.
getArrayJoinedColumns();
/// Push the predicate expression down to the sub-queries.
rewrite_sub_queries = PredicateExpressionsOptimizer(select_query, settings, context).optimize();
/// Delete the unnecessary from `source_columns` list. Create `unknown_required_source_columns`. Form `columns_added_by_join`.
collectUsedColumns();
......
......@@ -171,6 +171,7 @@ public:
/// Create Set-s that we can from IN section to use the index on them.
void makeSetsForIndex();
bool isRewriteSubQueriesPredicate() { return rewrite_sub_queries; }
private:
ASTPtr ast;
......@@ -243,6 +244,9 @@ private:
Tables external_tables;
size_t external_table_id = 1;
/// Predicate optimizer overrides the sub queries
bool rewrite_sub_queries = false;
/** Remove all unnecessary columns from the list of all available columns of the table (`columns`).
* At the same time, form a set of unknown columns (`unknown_required_source_columns`),
* as well as the columns added by JOIN (`columns_added_by_join`).
......
......@@ -43,6 +43,7 @@
#include <Core/Field.h>
#include <Columns/Collator.h>
#include <Common/typeid_cast.h>
#include <Parsers/queryToString.h>
namespace DB
......@@ -195,6 +196,10 @@ InterpreterSelectQuery::InterpreterSelectQuery(
for (const auto & it : query_analyzer->getExternalTables())
if (!context.tryGetExternalTable(it.first))
context.addExternalTable(it.first, it.second);
if (query_analyzer->isRewriteSubQueriesPredicate())
interpreter_subquery = std::make_unique<InterpreterSelectWithUnionQuery>(
table_expression, getSubqueryContext(context), required_columns, QueryProcessingStage::Complete, subquery_depth + 1, only_analyze);
}
if (interpreter_subquery)
......@@ -656,10 +661,11 @@ QueryProcessingStage::Enum InterpreterSelectQuery::executeFetchColumns(Pipeline
else if (interpreter_subquery)
{
/// Subquery.
/// If we need less number of columns that subquery have - update the interpreter.
if (required_columns.size() < source_header.columns())
{
interpreter_subquery = std::make_unique<InterpreterSelectWithUnionQuery>(
query.table(), getSubqueryContext(context), required_columns, QueryProcessingStage::Complete, subquery_depth + 1, only_analyze);
......
#include <Common/typeid_cast.h>
#include <Storages/IStorage.h>
#include <Interpreters/PredicateExpressionsOptimizer.h>
#include <Interpreters/InterpreterSelectQuery.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <Parsers/ASTSubquery.h>
#include <Parsers/queryToString.h>
#include <iostream>
namespace DB
{
static constexpr auto and_function_name = "and";
PredicateExpressionsOptimizer::PredicateExpressionsOptimizer(
ASTSelectQuery * ast_select_, const Settings & settings_, const Context & context_)
: ast_select(ast_select_), settings(settings_), context(context_)
{
}
bool PredicateExpressionsOptimizer::optimize()
{
if (!settings.enable_optimize_predicate_expression || !ast_select || !ast_select->tables)
return false;
SubQueriesProjectionColumns all_subquery_projection_columns;
getAllSubqueryProjectionColumns(ast_select->tables.get(), all_subquery_projection_columns);
bool is_rewrite_sub_queries = false;
if (!all_subquery_projection_columns.empty())
{
is_rewrite_sub_queries |= optimizeImpl(ast_select->where_expression, all_subquery_projection_columns, false);
is_rewrite_sub_queries |= optimizeImpl(ast_select->prewhere_expression, all_subquery_projection_columns, true);
}
return is_rewrite_sub_queries;
}
bool PredicateExpressionsOptimizer::optimizeImpl(
ASTPtr & outer_expression, SubQueriesProjectionColumns & sub_queries_projection_columns, bool is_prewhere)
{
/// split predicate with `and`
PredicateExpressions outer_predicate_expressions = splitConjunctionPredicate(outer_expression);
bool is_rewrite_subquery = false;
for (const auto & outer_predicate : outer_predicate_expressions)
{
ASTs outer_predicate_dependent;
getExpressionDependentColumns(outer_predicate, outer_predicate_dependent);
/// TODO: remove origin expression
for (const auto & subquery_projection_columns : sub_queries_projection_columns)
{
auto subquery = static_cast<ASTSelectQuery *>(subquery_projection_columns.first);
const ProjectionsWithAliases projection_columns = subquery_projection_columns.second;
OptimizeKind optimize_kind = OptimizeKind::NONE;
if (!cannotPushDownOuterPredicate(projection_columns, subquery, outer_predicate_dependent, is_prewhere, optimize_kind))
{
ASTPtr inner_predicate;
cloneOuterPredicateForInnerPredicate(outer_predicate, projection_columns, outer_predicate_dependent, inner_predicate);
switch(optimize_kind)
{
case OptimizeKind::NONE: continue;
case OptimizeKind::PUSH_TO_WHERE: is_rewrite_subquery |= optimizeExpression(inner_predicate, subquery->where_expression, subquery); continue;
case OptimizeKind::PUSH_TO_HAVING: is_rewrite_subquery |= optimizeExpression(inner_predicate, subquery->having_expression, subquery); continue;
case OptimizeKind::PUSH_TO_PREWHERE: is_rewrite_subquery |= optimizeExpression(inner_predicate, subquery->prewhere_expression, subquery); continue;
}
}
}
}
return is_rewrite_subquery;
}
PredicateExpressions PredicateExpressionsOptimizer::splitConjunctionPredicate(ASTPtr & predicate_expression)
{
PredicateExpressions predicate_expressions;
if (predicate_expression)
{
predicate_expressions.emplace_back(predicate_expression);
auto remove_expression_at_index = [&predicate_expressions] (const size_t index)
{
if (index < predicate_expressions.size() - 1)
std::swap(predicate_expressions[index], predicate_expressions.back());
predicate_expressions.pop_back();
};
for (size_t idx = 0; idx < predicate_expressions.size();)
{
const auto expression = predicate_expressions.at(idx);
if (const auto function = typeid_cast<ASTFunction *>(expression.get()))
{
if (function->name == and_function_name)
{
for (auto & child : function->arguments->children)
predicate_expressions.emplace_back(child);
remove_expression_at_index(idx);
continue;
}
}
idx++;
}
}
return predicate_expressions;
}
void PredicateExpressionsOptimizer::getExpressionDependentColumns(const ASTPtr & expression, ASTs & expression_dependent_columns)
{
if (!typeid_cast<ASTIdentifier *>(expression.get()))
{
for (const auto & child : expression->children)
getExpressionDependentColumns(child, expression_dependent_columns);
return;
}
expression_dependent_columns.emplace_back(expression);
}
bool PredicateExpressionsOptimizer::cannotPushDownOuterPredicate(
const ProjectionsWithAliases & subquery_projection_columns, ASTSelectQuery * subquery,
ASTs & expression_dependent_columns, bool & is_prewhere, OptimizeKind & optimize_kind)
{
if (subquery->final() || subquery->limit_by_expression_list || subquery->limit_offset || subquery->with_expression_list)
return true;
for (auto & dependent_column : expression_dependent_columns)
{
bool is_found = false;
String dependent_column_name = dependent_column->getAliasOrColumnName();
for (auto projection_column : subquery_projection_columns)
{
if (projection_column.second == dependent_column_name)
{
is_found = true;
optimize_kind = isAggregateFunction(projection_column.first) ? OptimizeKind::PUSH_TO_HAVING : optimize_kind;
}
}
if (!is_found)
return true;
}
if (optimize_kind == OptimizeKind::NONE)
optimize_kind = is_prewhere ? OptimizeKind::PUSH_TO_PREWHERE : OptimizeKind::PUSH_TO_WHERE;
return false;
}
bool PredicateExpressionsOptimizer::isAggregateFunction(ASTPtr & node)
{
if (auto function = typeid_cast<ASTFunction *>(node.get()))
{
if (AggregateFunctionFactory::instance().isAggregateFunctionName(function->name))
return true;
}
for (auto & child : node->children)
if (isAggregateFunction(child))
return true;
return false;
}
void PredicateExpressionsOptimizer::getAllSubqueryProjectionColumns(IAST * node, SubQueriesProjectionColumns & all_subquery_projection_columns)
{
if (auto ast_subquery = typeid_cast<ASTSubquery *>(node))
{
ASTs output_projection;
IAST * subquery = ast_subquery->children.at(0).get();
getSubqueryProjectionColumns(subquery, all_subquery_projection_columns, output_projection);
return;
}
for (auto & child : node->children)
getAllSubqueryProjectionColumns(child.get(), all_subquery_projection_columns);
}
void PredicateExpressionsOptimizer::cloneOuterPredicateForInnerPredicate(
const ASTPtr & outer_predicate, const ProjectionsWithAliases & projection_columns, ASTs & predicate_dependent_columns,
ASTPtr & inner_predicate)
{
inner_predicate = std::move(outer_predicate->clone());
ASTs new_expression_require_columns;
new_expression_require_columns.reserve(predicate_dependent_columns.size());
getExpressionDependentColumns(inner_predicate, new_expression_require_columns);
for (auto & expression : new_expression_require_columns)
{
if (auto identifier = typeid_cast<ASTIdentifier *>(expression.get()))
{
for (auto projection : projection_columns)
{
if (identifier->name == projection.second)
identifier->name = projection.first->getAliasOrColumnName();
}
}
}
}
bool PredicateExpressionsOptimizer::optimizeExpression(const ASTPtr & outer_expression, ASTPtr & subquery_expression, ASTSelectQuery * subquery)
{
ASTPtr new_subquery_expression = subquery_expression;
new_subquery_expression = new_subquery_expression ? makeASTFunction(and_function_name, outer_expression, subquery_expression) : outer_expression;
if (!subquery_expression)
subquery->children.emplace_back(new_subquery_expression);
else
for (auto & child : subquery->children)
if (child == subquery_expression)
child = new_subquery_expression;
subquery_expression = std::move(new_subquery_expression);
return true;
}
void PredicateExpressionsOptimizer::getSubqueryProjectionColumns(IAST * subquery, SubQueriesProjectionColumns & all_subquery_projection_columns, ASTs & output_projections)
{
if (auto * with_union_subquery = typeid_cast<ASTSelectWithUnionQuery *>(subquery))
for (auto & select : with_union_subquery->list_of_selects->children)
getSubqueryProjectionColumns(select.get(), all_subquery_projection_columns, output_projections);
if (auto * without_union_subquery = typeid_cast<ASTSelectQuery *>(subquery))
{
const auto expression_list = without_union_subquery->select_expression_list->children;
/// use first projection as the output projection
if (output_projections.empty())
output_projections = expression_list;
if (output_projections.size() != expression_list.size())
throw Exception("Number of columns doesn't match", ErrorCodes::NUMBER_OF_COLUMNS_DOESNT_MATCH);
ProjectionsWithAliases subquery_projections;
subquery_projections.reserve(expression_list.size());
for (size_t idx = 0; idx < expression_list.size(); idx++)
subquery_projections.emplace_back(std::pair(expression_list.at(idx), output_projections.at(idx)->getAliasOrColumnName()));
all_subquery_projection_columns.insert(std::pair(subquery, subquery_projections));
}
}
}
#pragma once
#include <Parsers/IAST.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Interpreters/Context.h>
#include <Interpreters/ExpressionActions.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int NUMBER_OF_COLUMNS_DOESNT_MATCH;
}
using PredicateExpressions = std::vector<ASTPtr>;
using ProjectionWithAlias = std::pair<ASTPtr, String>;
using ProjectionsWithAliases = std::vector<ProjectionWithAlias>;
using SubQueriesProjectionColumns = std::map<IAST *, ProjectionsWithAliases>;
/** This class provides functions for Push-Down predicate expressions
*
* The Example:
* - Query before optimization :
* SELECT id_1, name_1 FROM (SELECT id_1, name_1 FROM table_a UNION ALL SELECT id_2, name_2 FROM table_b)
* WHERE id_1 = 1
* - Query after optimization :
* SELECT id_1, name_1 FROM (SELECT id_1, name_1 FROM table_a WHERE id_1 = 1 UNION ALL SELECT id_2, name_2 FROM table_b WHERE id_2 = 1)
* WHERE id_1 = 1
* For more details : https://github.com/yandex/ClickHouse/pull/2015#issuecomment-374283452
*/
class PredicateExpressionsOptimizer
{
public:
PredicateExpressionsOptimizer(ASTSelectQuery * ast_select_, const Settings & settings_, const Context & context_);
bool optimize();
private:
ASTSelectQuery * ast_select;
const Settings & settings;
const Context & context;
enum OptimizeKind
{
NONE,
PUSH_TO_PREWHERE,
PUSH_TO_WHERE,
PUSH_TO_HAVING,
};
bool isAggregateFunction(ASTPtr & node);
PredicateExpressions splitConjunctionPredicate(ASTPtr & predicate_expression);
void getExpressionDependentColumns(const ASTPtr & expression, ASTs & expression_dependent_columns);
bool optimizeExpression(const ASTPtr & outer_expression, ASTPtr & subquery_expression, ASTSelectQuery * subquery);
bool optimizeImpl(ASTPtr & outer_expression, SubQueriesProjectionColumns & sub_queries_projection_columns, bool is_prewhere);
bool cannotPushDownOuterPredicate(
const ProjectionsWithAliases & subquery_projection_columns, ASTSelectQuery * subquery,
ASTs & expression_dependent_columns, bool & is_prewhere, OptimizeKind & optimize_kind);
void cloneOuterPredicateForInnerPredicate(
const ASTPtr & outer_predicate, const ProjectionsWithAliases & projection_columns, ASTs & predicate_dependent_columns,
ASTPtr & inner_predicate);
void getAllSubqueryProjectionColumns(IAST * node, SubQueriesProjectionColumns & all_subquery_projection_columns);
void getSubqueryProjectionColumns(IAST * subquery, SubQueriesProjectionColumns & all_subquery_projection_columns, ASTs & output_projections);
};
}
\ No newline at end of file
......@@ -266,6 +266,7 @@ struct Settings
M(SettingUInt64, enable_conditional_computation, 0, "Enable conditional computations") \
\
M(SettingDateTimeInputFormat, date_time_input_format, FormatSettings::DateTimeInputFormat::Basic, "Method to read DateTime from text input formats. Possible values: 'basic' and 'best_effort'.") \
M(SettingBool, enable_optimize_predicate_expression, 0, "") \
#define DECLARE(TYPE, NAME, DEFAULT, DESCRIPTION) \
TYPE NAME {DEFAULT};
......
1
1
1
1
2000-01-01 1 test string 1 1
1
1
2000-01-01 1 test string 1 1
2000-01-01 1 test string 1 1
2000-01-01 1
2000-01-01 1 test string 1 1
2000-01-01 1 test string 1 1
1 test string 1
1 test string 1
test string 1 1 1
test string 1 1 1
1
1
#!/usr/bin/env bash
CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
. $CURDIR/../shell_config.sh
exception_pattern="Code: 277.*is not used and setting 'force_primary_key' is set.."
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_union_1;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_union_2;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_join_1;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_join_2;"
${CLICKHOUSE_CLIENT} --query "CREATE TABLE test.test(date Date, id Int8, name String, value Int64) ENGINE = MergeTree(date, (id, date), 8192);"
${CLICKHOUSE_CLIENT} --query "CREATE TABLE test.test_union_1(date_1 Date, id_1 Int8, name_1 String, value_1 Int64) ENGINE = MergeTree(date_1, (id_1, date_1), 8192);"
${CLICKHOUSE_CLIENT} --query "CREATE TABLE test.test_union_2(date_2 Date, id_2 Int8, name_2 String, value_2 Int64) ENGINE = MergeTree(date_2, (id_2, date_2), 8192);"
${CLICKHOUSE_CLIENT} --query "CREATE TABLE test.test_join_1(date_1 Date, id_1 Int8, name_1 String, value_1 Int64) ENGINE = MergeTree(date_1, (id_1, date_1), 8192);"
${CLICKHOUSE_CLIENT} --query "CREATE TABLE test.test_join_2(date_2 Date, id_2 Int8, name_2 String, value_2 Int64) ENGINE = MergeTree(date_2, (id_2, date_2), 8192);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test VALUES('2000-01-01', 1, 'test string 1', 1);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test VALUES('2000-01-01', 2, 'test string 2', 2);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_union_1 VALUES('2000-01-01', 1, 'test string 1', 1);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_union_1 VALUES('2000-01-01', 2, 'test string 2', 2);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_union_2 VALUES('2000-01-01', 1, 'test string 1', 1);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_union_2 VALUES('2000-01-01', 2, 'test string 2', 2);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_join_1 VALUES('2000-01-01', 1, 'test string 1', 1);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_join_1 VALUES('2000-01-01', 2, 'test string 2', 2);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_join_2 VALUES('2000-01-01', 1, 'test string 1', 1);"
${CLICKHOUSE_CLIENT} --query "INSERT INTO test.test_join_2 VALUES('2000-01-01', 2, 'test string 2', 2);"
# Queries that previously worked but now don't work.
echo `${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query 'SELECT * FROM (SELECT 1) WHERE \`1\` = 1;' 2>&1 | grep -c "Unknown identifier: 1."`
# Not need push down, but it works.
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT 1;"
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT 1 AS id WHERE id = 1;"
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT arrayJoin([1,2,3]) AS id WHERE id = 1;"
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT * FROM test.test) WHERE id = 1;"
# Need push down
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT arrayJoin([1, 2, 3]) AS id) WHERE id = 1;"
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT id FROM (SELECT arrayJoin([1, 2, 3]) AS id) WHERE id = 1;"
${CLICKHOUSE_CLIENT} --enable_optimize_predicate_expression 1 --query "SELECT date, id, name, value FROM (SELECT date, name, value,min(id) AS id FROM test.test GROUP BY date, name, value) WHERE id = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT date, id, name, value FROM (SELECT date, id, name, value FROM test.test) WHERE id = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT date, id FROM (SELECT id, date, min(value) FROM test.test GROUP BY id, date) WHERE id = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT date_1, id_1, name_1, value_1 FROM (SELECT date_1, id_1, name_1, value_1 FROM test.test_union_1 UNION ALL SELECT date_2, id_2, name_2, value_2 FROM test.test_union_2) WHERE id_1 = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT id_1, name_1 AS name FROM test.test_join_1) ANY LEFT JOIN (SELECT id_2, name_2 AS name FROM test.test_join_2) USING name WHERE id_1 = 1 AND id_2 = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT id_1, name_1 AS name FROM test.test_join_1) ANY LEFT JOIN (SELECT id_2, name_2 AS name FROM test.test_union_2 UNION ALL SELECT id_1, name_1 AS name FROM test.test_union_1) USING name WHERE id_1 = 1 AND id_2 = 1;"
${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT name_1,id_1 AS id_1, id_1 AS id_2 FROM test.test_union_1 UNION ALL (SELECT name,id_1,id_2 FROM (SELECT name_1 AS name, id_1 FROM test.test_join_1) ANY INNER JOIN (SELECT name_2 AS name, id_2 FROM test.test_join_2) USING (name))) WHERE id_1 = 1 AND id_2 = 1;"
echo `${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT * FROM (SELECT * FROM test.test) WHERE id = 1;" 2>&1 | grep -c "$exception_pattern"`
echo `${CLICKHOUSE_CLIENT} --force_primary_key 1 --enable_optimize_predicate_expression 1 --query "SELECT id FROM (SELECT min(id) AS id FROM test.test) WHERE id = 1;" 2>&1 | grep -c "$exception_pattern"`
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_union_1;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_union_2;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_join_1;"
${CLICKHOUSE_CLIENT} --query "DROP TABLE IF EXISTS test.test_join_2;"
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册