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Bug #44290: explain crashes for subquery with distinct in

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SQL_SELECT::test_quick_select

The crash was caused by an incomplete cleanup of JOIN_TAB::select
during the filesort of rows for GROUP BY clause inside a subquery.
Queries where a quick index access is replaced with filesort was
was affected. For example:

  SELECT 1 FROM
    (SELECT COUNT(DISTINCT c1) FROM t1
       WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x

Quick index access related data in the SQL_SELECT::test_quick_select
function was inconsistent after an incomplete cleanup.
This function has been completed to prevent crashes in the
SQL_SELECT::test_quick_select function.


mysql-test/include/mix1.inc:
  Add test case for bug #44290.
mysql-test/r/innodb_mysql.result:
  Add test case for bug #44290.
sql/sql_select.cc:
  Bug #44290: explain crashes for subquery with distinct in
              SQL_SELECT::test_quick_select
  
  Quick index access related data in the SQL_SELECT::test_quick_select
  function was inconsistent after an incomplete cleanup.
  This function has been completed to prevent crashes in the
  SQL_SELECT::test_quick_select function.
This commit is contained in:
Gleb Shchepa 2009-05-13 12:51:39 +05:00
commit 585cf08fe6
3 changed files with 39 additions and 0 deletions
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19
mysql-test/include/mix1.inc
View file

@ -1516,4 +1516,23 @@ DROP TABLE t1;
# DROP TABLE t1;
#
--echo #
--echo # Bug #44290: explain crashes for subquery with distinct in
--echo # SQL_SELECT::test_quick_select
--echo # (reproduced only with InnoDB tables)
--echo #
eval
CREATE TABLE t1 (c1 INT, c2 INT, c3 INT, KEY (c3), KEY (c2, c3))
ENGINE=$engine_type;
INSERT INTO t1 VALUES (1,1,1), (1,1,1), (1,1,2), (1,1,1), (1,1,2);
SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
EXPLAIN
SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
DROP TABLE t1;
--echo End of 5.1 tests

19
mysql-test/r/innodb_mysql.result
View file

@ -1687,6 +1687,25 @@ vid tid idx name type
3 1 2 c1 NULL
3 1 1 pk NULL
DROP TABLE t1;
#
# Bug #44290: explain crashes for subquery with distinct in
# SQL_SELECT::test_quick_select
# (reproduced only with InnoDB tables)
#
CREATE TABLE t1 (c1 INT, c2 INT, c3 INT, KEY (c3), KEY (c2, c3))
ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,1,1), (1,1,1), (1,1,2), (1,1,1), (1,1,2);
SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
1
1
EXPLAIN
SELECT 1 FROM (SELECT COUNT(DISTINCT c1)
FROM t1 WHERE c2 IN (1, 1) AND c3 = 2 GROUP BY c2) x;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
2 DERIVED t1 index c3,c2 c2 10 NULL 5
DROP TABLE t1;
End of 5.1 tests
drop table if exists t1, t2, t3;
create table t1(a int);

1
sql/sql_select.cc
View file

@ -13471,6 +13471,7 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
{
select->cleanup(); // filesort did select
tab->select= 0;
table->quick_keys.clear_all(); // as far as we cleanup select->quick
}
tab->select_cond=0;
tab->last_inner= 0;