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Fixed LP bug #878199.

Browse source 
The function JOIN::drop_unused_derived_keys could erroneously set
the value of REF::key to 0 for a joined materialized view/derived table
in the case when no REF access to the table was used by the query
execution plan. This could cause a crash of the server.
This commit is contained in:
Igor Babaev 2011-10-20 04:59:20 -07:00
parent 0e4d88f1b2
commit e7a7e2a036
3 changed files with 46 additions and 1 deletions
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22
mysql-test/r/derived_view.result
View file

@ -1534,4 +1534,26 @@ id select_type table type possible_keys key key_len ref rows Extra
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using where
DROP VIEW v1;
DROP TABLE t1,t2;
#
# LP bug #878199: join of two materialized views
#
CREATE TABLE t1 (a int, b varchar(1)) ;
INSERT INTO t1 VALUES (7,'c'), (3,'h'), (7,'c');
CREATE TABLE t2 (b varchar(1)) ;
INSERT INTO t2 VALUES ('p'), ('c'), ('j'), ('c'), ('p');
CREATE VIEW v1 AS SELECT * FROM t1 GROUP BY a,b;
CREATE VIEW v2 AS SELECT * FROM t2 GROUP BY b;
SET SESSION optimizer_switch = 'derived_with_keys=on';
SELECT v1.a FROM v1,v2 WHERE v2.b = v1.b ORDER BY 1;
a
7
EXPLAIN
SELECT v1.a FROM v1,v2 WHERE v2.b = v1.b ORDER BY 1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL key0 NULL NULL NULL 3 Using where; Using filesort
1 PRIMARY <derived3> ref key0 key0 5 v1.b 2
3 DERIVED t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
2 DERIVED t1 ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
DROP VIEW v1,v2;
DROP TABLE t1,t2;
set optimizer_switch=@exit_optimizer_switch;

23
mysql-test/t/derived_view.test
View file

@ -973,5 +973,28 @@ SELECT v1.a FROM v1
DROP VIEW v1;
DROP TABLE t1,t2;
--echo #
--echo # LP bug #878199: join of two materialized views
--echo #
CREATE TABLE t1 (a int, b varchar(1)) ;
INSERT INTO t1 VALUES (7,'c'), (3,'h'), (7,'c');
CREATE TABLE t2 (b varchar(1)) ;
INSERT INTO t2 VALUES ('p'), ('c'), ('j'), ('c'), ('p');
CREATE VIEW v1 AS SELECT * FROM t1 GROUP BY a,b;
CREATE VIEW v2 AS SELECT * FROM t2 GROUP BY b;
SET SESSION optimizer_switch = 'derived_with_keys=on';
SELECT v1.a FROM v1,v2 WHERE v2.b = v1.b ORDER BY 1;
EXPLAIN
SELECT v1.a FROM v1,v2 WHERE v2.b = v1.b ORDER BY 1;
DROP VIEW v1,v2;
DROP TABLE t1,t2;
# The following command must be the last one the file
set optimizer_switch=@exit_optimizer_switch;

2
sql/sql_select.cc
View file

@ -8541,7 +8541,7 @@ void JOIN::drop_unused_derived_keys()
continue;
if (table->max_keys > 1)
table->use_index(tab->ref.key);
if (table->s->keys)
if (table->s->keys && tab->ref.key >= 0)
tab->ref.key= 0;
tab->keys= (key_map) (table->s->keys ? 1 : 0);
}