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Patch for Bug#13805127: Stored program cache produces wrong result in same THD.

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Background:

  - as described in MySQL Internals Prepared Stored
    (http://forge.mysql.com/wiki/MySQL_Internals_Prepared_Stored),
    the Optimizer sometimes does destructive changes to the parsed
    LEX-object (Item-tree), which makes it impossible to re-use
    that tree for PS/SP re-execution.

  - in order to be able to re-use the Item-tree, the destructive
    changes are remembered and rolled back after the statement execution.

The problem, discovered by this bug, was that the objects representing
GROUP-BY clause did not restored after query execution. So, the GROUP-BY
part of the statement could not be properly re-initialized for re-execution
after destructive changes.

Those objects do not take part in the Item-tree, so they can not be saved
using the approach for Item-tree.

The fix is as follows:

  - introduce a new array in st_select_lex to store the original
    ORDER pointers, representing the GROUP-BY clause;

  - Initialize this array in fix_prepare_information().

  - restore the list of GROUP-BY items in reinit_stmt_before_use().
This commit is contained in:
Tor Didriksen
2012-03-29 15:07:54 +02:00
parent 90436a096c
commit 71261282b1
8 changed files with 485 additions and 2 deletions
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103
mysql-test/r/ps.result
View File

@@ -3746,5 +3746,108 @@ FROM (SELECT 1 UNION SELECT 2) t;
1
1
2
# Bug#13805127: Stored program cache produces wrong result in same THD
PREPARE s1 FROM
"
SELECT c1, t2.c2, count(c3)
FROM
(
SELECT 3 as c2 FROM dual WHERE @x = 1
UNION
SELECT 2 FROM dual WHERE @x = 1 OR @x = 2
) AS t1,
(
SELECT '2012-03-01 01:00:00' AS c1, 3 as c2, 1 as c3 FROM dual
UNION
SELECT '2012-03-01 02:00:00', 3, 2 FROM dual
UNION
SELECT '2012-03-01 01:00:00', 2, 1 FROM dual
) AS t2
WHERE t2.c2 = t1.c2
GROUP BY c1, c2
";
SET @x = 1;
SELECT c1, t2.c2, count(c3)
FROM
(
SELECT 3 as c2 FROM dual WHERE @x = 1
UNION
SELECT 2 FROM dual WHERE @x = 1 OR @x = 2
) AS t1,
(
SELECT '2012-03-01 01:00:00' AS c1, 3 as c2, 1 as c3 FROM dual
UNION
SELECT '2012-03-01 02:00:00', 3, 2 FROM dual
UNION
SELECT '2012-03-01 01:00:00', 2, 1 FROM dual
) AS t2
WHERE t2.c2 = t1.c2
GROUP BY c1, c2;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
EXECUTE s1;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
SET @x = 2;
SELECT c1, t2.c2, count(c3)
FROM
(
SELECT 3 as c2 FROM dual WHERE @x = 1
UNION
SELECT 2 FROM dual WHERE @x = 1 OR @x = 2
) AS t1,
(
SELECT '2012-03-01 01:00:00' AS c1, 3 as c2, 1 as c3 FROM dual
UNION
SELECT '2012-03-01 02:00:00', 3, 2 FROM dual
UNION
SELECT '2012-03-01 01:00:00', 2, 1 FROM dual
) AS t2
WHERE t2.c2 = t1.c2
GROUP BY c1, c2;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
EXECUTE s1;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
SET @x = 1;
SELECT c1, t2.c2, count(c3)
FROM
(
SELECT 3 as c2 FROM dual WHERE @x = 1
UNION
SELECT 2 FROM dual WHERE @x = 1 OR @x = 2
) AS t1,
(
SELECT '2012-03-01 01:00:00' AS c1, 3 as c2, 1 as c3 FROM dual
UNION
SELECT '2012-03-01 02:00:00', 3, 2 FROM dual
UNION
SELECT '2012-03-01 01:00:00', 2, 1 FROM dual
) AS t2
WHERE t2.c2 = t1.c2
GROUP BY c1, c2;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
EXECUTE s1;
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
DEALLOCATE PREPARE s1;
#
# End of 5.5 tests.

38
mysql-test/r/sp.result
View File

@@ -7747,6 +7747,44 @@ CALL p2();
DROP PROCEDURE p1;
DROP PROCEDURE p2;
DROP TABLE t1;
# Bug#13805127: Stored program cache produces wrong result in same THD
CREATE PROCEDURE p1(x INT UNSIGNED)
BEGIN
SELECT c1, t2.c2, count(c3)
FROM
(
SELECT 3 as c2 FROM dual WHERE x = 1
UNION
SELECT 2 FROM dual WHERE x = 1 OR x = 2
) AS t1,
(
SELECT '2012-03-01 01:00:00' AS c1, 3 as c2, 1 as c3 FROM dual
UNION
SELECT '2012-03-01 02:00:00', 3, 2 FROM dual
UNION
SELECT '2012-03-01 01:00:00', 2, 1 FROM dual
) AS t2
WHERE t2.c2 = t1.c2
GROUP BY c1, c2
;
END|
CALL p1(1);
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
CALL p1(2);
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
CALL p1(1);
c1 c2 count(c3)
2012-03-01 01:00:00 2 1
2012-03-01 01:00:00 3 1
2012-03-01 02:00:00 3 1
DROP PROCEDURE p1;
# End of 5.5 test
#
# Bug#12663165 SP DEAD CODE REMOVAL DOESN'T UNDERSTAND CONTINUE HANDLERS