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Fix bug#11868 NOT NULL ref optimization in subquery used in update must be

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disabled if ref is built with a key from the updated table

Problem was in add_not_null_conds() optimization function.
It contains following code:
JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
...
add_cond_and_fix(&referred_tab->select_cond, notnull);
For UPDATE described in bug report referred_tab is 0 and dereferencing it
crashes the server.



sql/sql_select.cc:
  Fix bug #11868 NOT NULL ref optimization in subquery used in update must be
  disabled if ref is built with a key from the updated table
mysql-test/r/update.result:
  Test case for bug#11868 Update with subquery with ref built with a key from
  the updated table crashes server.
mysql-test/t/update.test:
  Test case for bug#11868 Update with subquery with ref built with a key from the updated table crashes server
This commit is contained in:
unknown
2005-07-16 05:31:16 +04:00
parent 0f41fb4234
commit 560ff1a2ea
3 changed files with 30 additions and 1 deletions
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7
sql/sql_select.cc
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@@ -3555,7 +3555,12 @@ static void add_not_null_conds(JOIN *join)
DBUG_ASSERT(item->type() == Item::FIELD_ITEM);
Item_field *not_null_item= (Item_field*)item;
JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
if (referred_tab->join != join)
/*
For UPDATE queries such as:
UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
not_null_item is the t1.f1, but it's referred_tab is 0.
*/
if (!referred_tab || referred_tab->join != join)
continue;
Item *notnull;
if (!(notnull= new Item_func_isnotnull(not_null_item)))