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ISSUE-5695: support push down predicate to final subquery

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This commit is contained in:
tai 2019-07-23 14:18:44 +08:00
parent adfc369172
commit b01f54ade1
5 changed files with 77 additions and 2 deletions
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3
dbms/src/Core/Settings.h
View File

@ -336,7 +336,8 @@ struct Settings : public SettingsCollection<Settings>
\
/** Obsolete settings that do nothing but left for compatibility reasons. Remove each one after half a year of obsolescence. */ \
\
M(SettingBool, allow_experimental_low_cardinality_type, true, "Obsolete setting, does nothing. Will be removed after 2019-08-13")
M(SettingBool, allow_experimental_low_cardinality_type, true, "Obsolete setting, does nothing. Will be removed after 2019-08-13") \
M(SettingBool, allow_push_predicate_to_final_subquery, 1, "Allow push predicate to final subquery.")
DECLARE_SETTINGS_COLLECTION(LIST_OF_SETTINGS)

5
dbms/src/Interpreters/PredicateExpressionsOptimizer.cpp
View File

@ -138,7 +138,10 @@ bool PredicateExpressionsOptimizer::allowPushDown(
const std::vector<IdentifierWithQualifier> & dependencies,
OptimizeKind & optimize_kind)
{
if (!subquery || subquery->final() || subquery->limitBy() || subquery->limitLength() || subquery->with())
if (!subquery ||
(!settings.allow_push_predicate_to_final_subquery && subquery->final()) ||
subquery->limitBy() || subquery->limitLength() ||
subquery->with())
return false;
else
{

4
dbms/src/Interpreters/PredicateExpressionsOptimizer.h
View File

@ -37,6 +37,9 @@ class PredicateExpressionsOptimizer
const UInt64 max_expanded_ast_elements;
const String count_distinct_implementation;
/// for final PredicatePushOptimizer
const bool allow_push_predicate_to_final_subquery;
/// for PredicateExpressionsOptimizer
const bool enable_optimize_predicate_expression;
const bool join_use_nulls;
@ -46,6 +49,7 @@ class PredicateExpressionsOptimizer
: max_ast_depth(settings.max_ast_depth),
max_expanded_ast_elements(settings.max_expanded_ast_elements),
count_distinct_implementation(settings.count_distinct_implementation),
allow_push_predicate_to_final_subquery(settings.allow_push_predicate_to_final_subquery),
enable_optimize_predicate_expression(settings.enable_optimize_predicate_expression),
join_use_nulls(settings.join_use_nulls)
{}

50
dbms/tests/queries/0_stateless/00974_final_predicate_push_down.reference Normal file
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@ -0,0 +1,50 @@
{
"meta":
[
{
"name": "COUNT()",
"type": "UInt64"
}
],
"data":
[
{
"COUNT()": "1"
}
],
"rows": 1,
"statistics":
{
"elapsed": 0.000780393,
"rows_read": 4,
"bytes_read": 16
}
}
{
"meta":
[
{
"name": "COUNT()",
"type": "UInt64"
}
],
"data":
[
{
"COUNT()": "1"
}
],
"rows": 1,
"statistics":
{
"elapsed": 0.000687364,
"rows_read": 2,
"bytes_read": 8
}
}

17
dbms/tests/queries/0_stateless/00974_final_predicate_push_down.sql Normal file
View File

@ -0,0 +1,17 @@
DROP TABLE IF EXISTS test_00974;
CREATE TABLE test_00974
(
date Date,
x Int32,
ver UInt64
)
ENGINE = ReplacingMergeTree(date, x, 4096);
INSERT INTO test_00974 VALUES ('2019-07-23', 1, 1), ('2019-07-23', 1, 2);
INSERT INTO test_00974 VALUES ('2019-07-23', 2, 1), ('2019-07-23', 2, 2);
SELECT COUNT() FROM (SELECT * FROM test_00974 FINAL) where x = 1 SETTINGS allow_push_predicate_to_final_subquery = 0 FORMAT JSON ;
SELECT COUNT() FROM (SELECT * FROM test_00974 FINAL) where x = 1 SETTINGS allow_push_predicate_to_final_subquery = 1 FORMAT JSON ;
DROP TABLE test_00974;