thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-27 18:12:02 +00:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #52297 from amosbird/fix_52055

Browse Source 
Don't use minmax_count projections when counting nullable columns
This commit is contained in:
Alexey Milovidov 2023-07-22 20:39:12 +03:00 committed by GitHub
commit 758ec9fa92
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 17 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
src/Processors/QueryPlan/Optimizations/optimizeUseAggregateProjection.cpp
View File

@ -92,18 +92,6 @@ static AggregateProjectionInfo getAggregatingProjectionInfo(
return info;
}
static bool hasNullableOrMissingColumn(const DAGIndex & index, const Names & names)
{
for (const auto & query_name : names)
{
auto jt = index.find(query_name);
if (jt == index.end() || jt->second->result_type->isNullable())
return true;
}
return false;
}
struct AggregateFunctionMatch
{
const AggregateDescription * description = nullptr;
@ -170,20 +158,14 @@ std::optional<AggregateFunctionMatches> matchAggregateFunctions(
}
/// This is a special case for the function count().
/// We can assume that 'count(expr) == count()' if expr is not nullable.
if (typeid_cast<const AggregateFunctionCount *>(candidate.function.get()))
/// We can assume that 'count(expr) == count()' if expr is not nullable,
/// which can be verified by simply casting to `AggregateFunctionCount *`.
if (typeid_cast<const AggregateFunctionCount *>(aggregate.function.get()))
{
bool has_nullable_or_missing_arg = false;
has_nullable_or_missing_arg |= hasNullableOrMissingColumn(query_index, aggregate.argument_names);
has_nullable_or_missing_arg |= hasNullableOrMissingColumn(proj_index, candidate.argument_names);
if (!has_nullable_or_missing_arg)
{
/// we can ignore arguments for count()
found_match = true;
res.push_back({&candidate, DataTypes()});
break;
}
/// we can ignore arguments for count()
found_match = true;
res.push_back({&candidate, DataTypes()});
break;
}
/// Now, function names and types matched.

1
tests/queries/0_stateless/01710_minmax_count_projection_count_nullable.reference Normal file
View File

@ -0,0 +1 @@
1

9
tests/queries/0_stateless/01710_minmax_count_projection_count_nullable.sql Normal file
View File

@ -0,0 +1,9 @@
DROP TABLE IF EXISTS test;
CREATE TABLE test (`val` LowCardinality(Nullable(String))) ENGINE = MergeTree ORDER BY tuple() SETTINGS index_granularity = 8192;
insert into test select number == 3 ? 'some value' : null from numbers(5);
SELECT count(val) FROM test SETTINGS optimize_use_implicit_projections = 1;
DROP TABLE test;