diff options
Diffstat (limited to 'sql/opt_range.cc')
| -rw-r--r-- | sql/opt_range.cc | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 04cc0baa0aa..634c9db18a8 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -3604,9 +3604,18 @@ static SEL_TREE *get_mm_tree(PARAM *param,COND *cond) /* Here when simple cond */ if (cond->const_item()) { - if (cond->val_int()) - DBUG_RETURN(new SEL_TREE(SEL_TREE::ALWAYS)); - DBUG_RETURN(new SEL_TREE(SEL_TREE::IMPOSSIBLE)); + /* + During the cond->val_int() evaluation we can come across a subselect + item which may allocate memory on the thd->mem_root and assumes + all the memory allocated has the same life span as the subselect + item itself. So we have to restore the thread's mem_root here. + */ + MEM_ROOT *tmp_root= param->mem_root; + param->thd->mem_root= param->old_root; + tree= cond->val_int() ? new(tmp_root) SEL_TREE(SEL_TREE::ALWAYS) : + new(tmp_root) SEL_TREE(SEL_TREE::IMPOSSIBLE); + param->thd->mem_root= tmp_root; + DBUG_RETURN(tree); } table_map ref_tables= 0; |