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Fix for bug #18306: MySQL crashes and restarts using subquery

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mysql-test/r/subselect.result:
  Fix for bug #18306: MySQL crashes and restarts using subquery
  test case
mysql-test/t/subselect.test:
  Fix for bug #18306: MySQL crashes and restarts using subquery
  test case
sql/opt_range.cc:
  Fix for bug #18306: MySQL crashes and restarts using subquery
  Restore thd->mem_root because
  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.
This commit is contained in:
unknown
2006-03-23 18:09:35 +04:00
parent 0ef3cd6c70
commit abffce9cad
3 changed files with 29 additions and 3 deletions
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15
sql/opt_range.cc
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@ -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;