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Bug #37348: Crash in or immediately after JOIN::make_sum_func_list

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The optimizer pulls up aggregate functions which should be aggregated in
an outer select. At some point it may substitute such a function for a field
in the temporary table. The setup_copy_fields function doesn't take this
into account and may overrun the copy_field buffer.
      
Fixed by filtering out the fields referenced through the specialized
reference for aggregates (Item_aggregate_ref).
Added an assertion to make sure bugs that cause similar discrepancy 
don't go undetected.

mysql-test/r/func_group.result:
  Bug #37348: test case
mysql-test/t/func_group.test:
  Bug #37348: test case
sql/item.cc:
  Bug #37348: Added a way to distinguish Item_aggregate_ref from the other types of refs
sql/item.h:
  Bug #37348: Added a way to distinguish Item_aggregate_ref from the other types of refs
sql/sql_select.cc:
  Bug #37348: 
   - Don't consider copying field references
      seen through Item_aggregate_ref
   - check for discrepancies between the number of expected 
     fields that need copying and the actual fields copied.
This commit is contained in:
Georgi Kodinov
2008-10-02 17:44:49 +03:00
parent 6037e8ec49
commit a18639b634
5 changed files with 89 additions and 2 deletions
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11
sql/sql_select.cc
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@@ -14804,6 +14804,7 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
Item *pos;
List_iterator_fast<Item> li(all_fields);
Copy_field *copy= NULL;
IF_DBUG(Copy_field *copy_start);
res_selected_fields.empty();
res_all_fields.empty();
List_iterator_fast<Item> itr(res_all_fields);
@@ -14816,12 +14817,19 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
goto err2;
param->copy_funcs.empty();
IF_DBUG(copy_start= copy);
for (i= 0; (pos= li++); i++)
{
Field *field;
uchar *tmp;
Item *real_pos= pos->real_item();
if (real_pos->type() == Item::FIELD_ITEM)
/*
Aggregate functions can be substituted for fields (by e.g. temp tables).
We need to filter those substituted fields out.
*/
if (real_pos->type() == Item::FIELD_ITEM &&
!(real_pos != pos &&
((Item_ref *)pos)->ref_type() == Item_ref::AGGREGATE_REF))
{
Item_field *item;
if (!(item= new Item_field(thd, ((Item_field*) real_pos))))
@@ -14868,6 +14876,7 @@ setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
goto err;
if (copy)
{
DBUG_ASSERT (param->field_count > (uint) (copy - copy_start));
copy->set(tmp, item->result_field);
item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
#ifdef HAVE_purify