thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-23 16:12:01 +00:00
Code Issues Packages Projects Releases Wiki Activity

fix order by optimization with monotonous functions

Browse Source
This commit is contained in:
Anton Popov 2020-11-13 02:33:26 +03:00
parent 6e62108606
commit a03b6df897
6 changed files with 103 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/Interpreters/TreeOptimizer.cpp
View File

@ -26,6 +26,7 @@
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Functions/FunctionFactory.h>
#include <Storages/StorageInMemoryMetadata.h>
namespace DB
@ -438,7 +439,8 @@ void optimizeDuplicateDistinct(ASTSelectQuery & select)
/// Replace monotonous functions in ORDER BY if they don't participate in GROUP BY expression,
/// has a single argument and not an aggregate functions.
void optimizeMonotonousFunctionsInOrderBy(ASTSelectQuery * select_query, const Context & context,
const TablesWithColumns & tables_with_columns)
const TablesWithColumns & tables_with_columns,
const Names & sorting_key_columns)
{
auto order_by = select_query->orderBy();
if (!order_by)
@ -455,13 +457,22 @@ void optimizeMonotonousFunctionsInOrderBy(ASTSelectQuery * select_query, const C
}
}
for (auto & child : order_by->children)
bool is_sorting_key_prefix = true;
for (size_t i = 0; i < order_by->children.size(); ++i)
{
auto * order_by_element = child->as<ASTOrderByElement>();
auto * order_by_element = order_by->children[i]->as<ASTOrderByElement>();
auto & ast_func = order_by_element->children[0];
if (!ast_func->as<ASTFunction>())
continue;
if (i >= sorting_key_columns.size() || ast_func->getColumnName() != sorting_key_columns[i])
is_sorting_key_prefix = false;
/// If order by expression matches the sorting key, do not remove
/// functions to allow execute reading in order of key.
if (is_sorting_key_prefix)
continue;
MonotonicityCheckVisitor::Data data{tables_with_columns, context, group_by_hashes};
MonotonicityCheckVisitor(data).visit(ast_func);
@ -611,7 +622,8 @@ void TreeOptimizer::optimizeIf(ASTPtr & query, Aliases & aliases, bool if_chain_
void TreeOptimizer::apply(ASTPtr & query, Aliases & aliases, const NameSet & source_columns_set,
const std::vector<TableWithColumnNamesAndTypes> & tables_with_columns,
const Context & context, bool & rewrite_subqueries)
const Context & context, const StorageMetadataPtr & metadata_snapshot,
bool & rewrite_subqueries)
{
const auto & settings = context.getSettingsRef();
@ -652,9 +664,6 @@ void TreeOptimizer::apply(ASTPtr & query, Aliases & aliases, const NameSet & sou
optimizeAggregateFunctionsOfGroupByKeys(select_query, query);
}
/// Remove duplicate items from ORDER BY.
optimizeDuplicatesInOrderBy(select_query);
/// Remove duplicate ORDER BY and DISTINCT from subqueries.
if (settings.optimize_duplicate_order_by_and_distinct)
{
@ -672,7 +681,13 @@ void TreeOptimizer::apply(ASTPtr & query, Aliases & aliases, const NameSet & sou
/// Replace monotonous functions with its argument
if (settings.optimize_monotonous_functions_in_order_by)
optimizeMonotonousFunctionsInOrderBy(select_query, context, tables_with_columns);
optimizeMonotonousFunctionsInOrderBy(select_query, context, tables_with_columns,
metadata_snapshot ? metadata_snapshot->getSortingKeyColumns() : Names{});
/// Remove duplicate items from ORDER BY.
/// Execute it after all order by optimizations,
/// because they can produce duplicated columns.
optimizeDuplicatesInOrderBy(select_query);
/// If function "if" has String-type arguments, transform them into enum
if (settings.optimize_if_transform_strings_to_enum)

5
src/Interpreters/TreeOptimizer.h
View File

@ -8,6 +8,8 @@ namespace DB
{
class Context;
struct StorageInMemoryMetadata;
using StorageMetadataPtr = std::shared_ptr<const StorageInMemoryMetadata>;
/// Part of of Tree Rewriter (SyntaxAnalyzer) that optimizes AST.
/// Query should be ready to execute either before either after it. But resulting query could be faster.
@ -16,7 +18,8 @@ class TreeOptimizer
public:
static void apply(ASTPtr & query, Aliases & aliases, const NameSet & source_columns_set,
const std::vector<TableWithColumnNamesAndTypes> & tables_with_columns,
const Context & context, bool & rewrite_subqueries);
const Context & context, const StorageMetadataPtr & metadata_snapshot,
bool & rewrite_subqueries);
static void optimizeIf(ASTPtr & query, Aliases & aliases, bool if_chain_to_multiif);
};

2
src/Interpreters/TreeRewriter.cpp
View File

@ -645,7 +645,7 @@ TreeRewriterResultPtr TreeRewriter::analyzeSelect(
/// Executing scalar subqueries - replacing them with constant values.
executeScalarSubqueries(query, context, subquery_depth, result.scalars, select_options.only_analyze);
TreeOptimizer::apply(query, result.aliases, source_columns_set, tables_with_columns, context, result.rewrite_subqueries);
TreeOptimizer::apply(query, result.aliases, source_columns_set, tables_with_columns, context, result.metadata_snapshot, result.rewrite_subqueries);
/// array_join_alias_to_name, array_join_result_to_source.
getArrayJoinedColumns(query, result, select_query, result.source_columns, source_columns_set);

12
tests/queries/0_stateless/01321_monotonous_functions_in_order_by.reference
View File

@ -54,14 +54,10 @@ FROM numbers(3)
ORDER BY exp(number) ASC
SELECT roundToExp2(number) AS x
FROM numbers(3)
ORDER BY
number ASC,
number ASC
ORDER BY number ASC
SELECT number AS x
FROM numbers(3)
ORDER BY
number ASC,
number ASC
ORDER BY number ASC
SELECT number
FROM numbers(3)
ORDER BY number DESC
@ -79,9 +75,7 @@ FROM numbers(3)
ORDER BY exp(number) DESC
SELECT roundToExp2(number) AS x
FROM numbers(3)
ORDER BY
number DESC,
number DESC
ORDER BY number DESC
0
1
2

46
tests/queries/0_stateless/01562_optimize_monotonous_functions_in_order_by.reference Normal file
View File

@ -0,0 +1,46 @@
SELECT
timestamp,
key
FROM test_order_by
ORDER BY timestamp ASC
LIMIT 10
Expression (Projection)
Limit (preliminary LIMIT)
MergingSorted (Merge sorted streams for ORDER BY)
MergeSorting (Merge sorted blocks for ORDER BY)
PartialSorting (Sort each block for ORDER BY)
Expression (Before ORDER BY and SELECT)
SettingQuotaAndLimits (Set limits and quota after reading from storage)
ReadFromStorage (MergeTree)
SELECT
timestamp,
key
FROM test_order_by
ORDER BY toDate(timestamp) ASC
LIMIT 10
Expression (Projection)
Limit (preliminary LIMIT)
FinishSorting
Expression (Before ORDER BY and SELECT)
SettingQuotaAndLimits (Set limits and quota after reading from storage)
ReadFromStorage (MergeTree with order)
SELECT
timestamp,
key
FROM test_order_by
ORDER BY
toDate(timestamp) ASC,
timestamp ASC
LIMIT 10
Expression (Projection)
Limit (preliminary LIMIT)
FinishSorting
Expression (Before ORDER BY and SELECT)
SettingQuotaAndLimits (Set limits and quota after reading from storage)
ReadFromStorage (MergeTree with order)
SELECT
timestamp,
key
FROM test_order_by
ORDER BY timestamp ASC
LIMIT 10

26
tests/queries/0_stateless/01562_optimize_monotonous_functions_in_order_by.sql Normal file
View File

@ -0,0 +1,26 @@
SET optimize_monotonous_functions_in_order_by = 1;
DROP TABLE IF EXISTS test_order_by;
CREATE TABLE test_order_by (timestamp DateTime, key UInt32) ENGINE=MergeTree() ORDER BY (toDate(timestamp), key);
INSERT INTO test_order_by SELECT now() + toIntervalSecond(number), number % 4 FROM numbers(10000);
OPTIMIZE TABLE test_order_by FINAL;
EXPLAIN SYNTAX SELECT * FROM test_order_by ORDER BY timestamp LIMIT 10;
EXPLAIN PLAN SELECT * FROM test_order_by ORDER BY timestamp LIMIT 10;
EXPLAIN SYNTAX SELECT * FROM test_order_by ORDER BY toDate(timestamp) LIMIT 10;
EXPLAIN PLAN SELECT * FROM test_order_by ORDER BY toDate(timestamp) LIMIT 10;
EXPLAIN SYNTAX SELECT * FROM test_order_by ORDER BY toDate(timestamp), timestamp LIMIT 10;
EXPLAIN PLAN SELECT * FROM test_order_by ORDER BY toDate(timestamp), timestamp LIMIT 10;
DROP TABLE IF EXISTS test_order_by;
CREATE TABLE test_order_by (timestamp DateTime, key UInt32) ENGINE=MergeTree() ORDER BY tuple();
INSERT INTO test_order_by SELECT now() + toIntervalSecond(number), number % 4 FROM numbers(10000);
OPTIMIZE TABLE test_order_by FINAL;
EXPLAIN SYNTAX SELECT * FROM test_order_by ORDER BY toDate(timestamp), timestamp LIMIT 10;
DROP TABLE IF EXISTS test_order_by;