diff options
Diffstat (limited to 'sql/opt_index_cond_pushdown.cc')
| -rw-r--r-- | sql/opt_index_cond_pushdown.cc | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/sql/opt_index_cond_pushdown.cc b/sql/opt_index_cond_pushdown.cc index ba6aece7377..df9dae8e442 100644 --- a/sql/opt_index_cond_pushdown.cc +++ b/sql/opt_index_cond_pushdown.cc @@ -345,13 +345,23 @@ void push_index_cond(JOIN_TAB *tab, uint keyno) { DBUG_ENTER("push_index_cond"); Item *idx_cond; - + + /* + Backported the following from MySQL 5.6: + 6. The index is not a clustered index. The performance improvement + of pushing an index condition on a clustered key is much lower + than on a non-clustered key. This restriction should be + re-evaluated when WL#6061 is implemented. + */ if ((tab->table->file->index_flags(keyno, 0, 1) & HA_DO_INDEX_COND_PUSHDOWN) && optimizer_flag(tab->join->thd, OPTIMIZER_SWITCH_INDEX_COND_PUSHDOWN) && tab->join->thd->lex->sql_command != SQLCOM_UPDATE_MULTI && tab->join->thd->lex->sql_command != SQLCOM_DELETE_MULTI && - tab->type != JT_CONST && tab->type != JT_SYSTEM) + tab->type != JT_CONST && tab->type != JT_SYSTEM && + !(keyno == tab->table->s->primary_key && // (6) + tab->table->file->primary_key_is_clustered())) // (6) + { DBUG_EXECUTE("where", print_where(tab->select_cond, "full cond", QT_ORDINARY);); |