diff options
| author | unknown <Sinisa@sinisa.nasamreza.org> | 2004-05-15 16:13:08 +0300 |
|---|---|---|
| committer | unknown <Sinisa@sinisa.nasamreza.org> | 2004-05-15 16:13:08 +0300 |
| commit | 90e87293cbc9489ffc51a8883087398564579067 (patch) | |
| tree | 862953df7fbfe45e6cebbc31e62bc9326f0911fe /sql/sql_union.cc | |
| parent | c6bc3cfb8457332b4519efcd10339c2632626acb (diff) | |
| download | mariadb-git-90e87293cbc9489ffc51a8883087398564579067.tar.gz | |
Optimising UNION ALL (WL 1687)
Diffstat (limited to 'sql/sql_union.cc')
| -rw-r--r-- | sql/sql_union.cc | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/sql/sql_union.cc b/sql/sql_union.cc index 63638b618d9..e6568f5f598 100644 --- a/sql/sql_union.cc +++ b/sql/sql_union.cc @@ -339,8 +339,8 @@ int st_select_lex_unit::exec() item->reset(); table->file->delete_all_rows(); } - if (union_distinct) // for subselects - table->file->extra(HA_EXTRA_CHANGE_KEY_TO_UNIQUE); + if (union_distinct && table->file->enable_indexes(HA_KEY_SWITCH_ALL)) + DBUG_RETURN(1); // For sub-selects for (SELECT_LEX *sl= select_cursor; sl; sl= sl->next_select()) { ha_rows records_at_start= 0; @@ -392,7 +392,11 @@ int st_select_lex_unit::exec() records_at_start= table->file->records; sl->join->exec(); if (sl == union_distinct) - table->file->extra(HA_EXTRA_CHANGE_KEY_TO_DUP); + { + if (table->file->disable_indexes(HA_KEY_SWITCH_ALL)) + DBUG_RETURN(1); + table->no_keyread=1; + } res= sl->join->error; offset_limit_cnt= sl->offset_limit; if (!res && union_result->flush()) |