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Fixed bug#36005: server crashes inside NOT IN clause subquery with

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impossible WHERE/HAVING clause
                 (subselect_single_select_engine::exec).

Allocation and initialization of joined table list t1, t2... of
subqueries like:

    NOT IN (SELECT ... FROM t1,t2,... WHERE 0)

is optimized out, however server tries to traverse this list.


mysql-test/r/subselect3.result:
  Added test case for bug#36005.
mysql-test/t/subselect3.test:
  Added test case for bug#36005.
sql/sql_select.cc:
  Fixed bug#36005.
  
  1. JOIN::prepare initializes JOIN::table counter (actually a size
     of the JOIN::join_tab array) and sets it to a number of joined tables.
  
  2. The make_join_statistics function (when called from JOIN::optimize)
     allocates and fills the JOIN::join_tab array.
     However, when optimizing subselect has impossible (definite false)
     WHERE or HAVING clause, optimizer skips call to make_join_statistics
     and leaves JOIN::join_tab == NULL.
  
  3. subselect_single_select_engine::exec does traversal of the JOIN::join_tab
     array and the server dies because array is not allocated but array
     counter is greater than 0.
  
  The JOIN::optimize method has been modified to reset the JOIN::table
  counter to 0 in cause of impossible WHERE/HAVING clause.
This commit is contained in:
unknown
2008-04-23 02:27:23 +05:00
parent 1c1f0a62e1
commit 73f7de59c2
3 changed files with 23 additions and 0 deletions
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1
sql/sql_select.cc
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@@ -832,6 +832,7 @@ JOIN::optimize()
"Impossible HAVING" : "Impossible WHERE"));
zero_result_cause= having_value == Item::COND_FALSE ?
"Impossible HAVING" : "Impossible WHERE";
tables= 0;
error= 0;
DBUG_RETURN(0);
}