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Fix bug lp:782305

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Analysis:
Both the wrong result and the valgrind warning were a result
of incomplete cleanup of the MIN/MAX subquery rewrite. At the
first execution of the query, the non-aggregate subquery is
transformed into an aggregate MIN/MAX subquery. During the
fix_fields phase of the MIN/MAX function, it sets the property
st_select_lex::with_sum_func to true.

The second execution of the query finds this flag to be ON.
When optimization reaches the same MIN/MAX subquery
transformation, it tests if the subquery is an aggregate or not.
Since select_lex->with_sum_func == true from the previous
execution, the transformation executes the second branch that
handles aggregate subqueries. This substitutes the subquery
Item into a Item_maxmin_subselect. At the same time elsewhere
it is assumed that the subquery Item is of type
Item_allany_subselect. Ultimately this results in casting the
actual object to the wrong class, and calling the wrong
any_value() method from empty_underlying_subquery().

Solution:
Cleanup the st_select_lex::with_sum_func property in the case
when the MIN/MAX transformation was performed for a non-aggregate
subquery, so that the transformation can be repeated.
This commit is contained in:
unknown
2011-07-18 23:45:38 +03:00
parent cc0195d6a1
commit c9e236828e
5 changed files with 94 additions and 9 deletions
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30
mysql-test/r/subselect4.result
View File

@ -2060,4 +2060,34 @@ WHERE t1.f4 IN ( SELECT f4 FROM t2 ) ;
f4
set @@optimizer_switch = @old_optimizer_switch;
drop table t1, t2, t3;
#
# LP BUG#782305: Wrong result/valgrind warning in Item_sum_hybrid::any_value()
#
CREATE TABLE t1 ( f1 int) ;
INSERT INTO t1 VALUES (2),(3);
CREATE TABLE t2 (f2 int) ;
INSERT INTO t2 VALUES (2),(3);
PREPARE st1 FROM '
SELECT * FROM t2
WHERE f2 <= SOME ( SELECT f1 FROM t1 );
';
EXECUTE st1;
f2
2
3
EXECUTE st1;
f2
2
3
PREPARE st2 FROM '
SELECT * FROM t2
WHERE f2 <= SOME (SELECT f1-2 FROM t1 UNION SELECT f1-1 FROM t1);
';
EXECUTE st2;
f2
2
EXECUTE st2;
f2
2
drop table t1, t2;
set optimizer_switch=@subselect4_tmp;

27
mysql-test/t/subselect4.test
View File

@ -1700,4 +1700,31 @@ set @@optimizer_switch = @old_optimizer_switch;
drop table t1, t2, t3;
--echo #
--echo # LP BUG#782305: Wrong result/valgrind warning in Item_sum_hybrid::any_value()
--echo #
CREATE TABLE t1 ( f1 int) ;
INSERT INTO t1 VALUES (2),(3);
CREATE TABLE t2 (f2 int) ;
INSERT INTO t2 VALUES (2),(3);
PREPARE st1 FROM '
SELECT * FROM t2
WHERE f2 <= SOME ( SELECT f1 FROM t1 );
';
EXECUTE st1;
EXECUTE st1;
PREPARE st2 FROM '
SELECT * FROM t2
WHERE f2 <= SOME (SELECT f1-2 FROM t1 UNION SELECT f1-1 FROM t1);
';
EXECUTE st2;
EXECUTE st2;
drop table t1, t2;
set optimizer_switch=@subselect4_tmp;