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This commit is contained in:
Anton Popov 2020-11-27 15:47:27 +03:00
parent f2106f9683
commit 1a4ed07a98
1 changed files with 6 additions and 1 deletions
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7
src/Storages/MergeTree/MergeTreeWhereOptimizer.h
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@ -25,6 +25,7 @@ using StorageMetadataPtr = std::shared_ptr<const StorageInMemoryMetadata>;
*
* If there are "good" conditions present in WHERE, the one with minimal summary column size is transferred to PREWHERE.
* Otherwise any condition with minimal summary column size can be transferred to PREWHERE.
* If column sizes are unknown (in compact parts), the number of columns, participating in condition is used instead.
*/
class MergeTreeWhereOptimizer : private boost::noncopyable
{
@ -45,12 +46,16 @@ private:
ASTPtr node;
UInt64 columns_size = 0;
NameSet identifiers;
/// Can condition be moved to prewhere?
bool viable = false;
/// Does the condition presumably have good selectivity?
bool good = false;
auto tuple() const
{
return std::make_tuple(!viable, !good, columns_size);
return std::make_tuple(!viable, !good, columns_size, identifiers.size());
}
/// Is condition a better candidate for moving to PREWHERE?