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MDEV-13784: query causes seg fault

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When we have a nested subquery then a subquery that was a dependent subquery
may change to an independent one when we optimizer the inner subqueries.
This is handled st_select_lex::optimize_unflattened_subqueries.
Currently a subquery that was changed to independent from dependent after optimization
phase incorrectly shows dependent in the output of Explain, this happens because we
don't update used_tables for the WHERE clause, ON clause, etc after the optimization phase.
This commit is contained in:
Varun Gupta
2019-01-06 23:15:25 +05:30
parent b87eb04f77
commit d0d0f88f2c
5 changed files with 78 additions and 4 deletions
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4
mysql-test/r/subselect_exists2in.result
View File

@ -330,7 +330,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
3 MATERIALIZED t3 ALL NULL NULL NULL NULL 2 100.00 Using where
Warnings:
Note 1276 Field or reference 'test.t2.b' of SELECT #3 was resolved in SELECT #2
Note 1003 select (select 1 from dual where (not(((1 is not null) and <in_optimizer>(1,1 in ( <materialize> (select `test`.`t3`.`c` from `test`.`t3` where (`test`.`t3`.`c` is not null) ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `<subquery3>`.`c`))))))))) AS `( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )` from `test`.`t1`
Note 1003 select (select 1 from dual where (not(((1 is not null) and <in_optimizer>(1,1 in (<primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `<subquery3>`.`c`))))))))) AS `( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )` from `test`.`t1`
SELECT ( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) ) FROM t1;
( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )
1
@ -344,7 +344,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
3 MATERIALIZED t3 ALL NULL NULL NULL NULL 2 100.00 Using where
Warnings:
Note 1276 Field or reference 'test.t2.b' of SELECT #3 was resolved in SELECT #2
Note 1003 select (select 1 from dual where (not(((1 is not null) and <in_optimizer>(1,1 in ( <materialize> (select `test`.`t3`.`c` from `test`.`t3` where (`test`.`t3`.`c` is not null) ), <primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `<subquery3>`.`c`))))))))) AS `( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )` from `test`.`t1`
Note 1003 select (select 1 from dual where (not(((1 is not null) and <in_optimizer>(1,1 in (<primary_index_lookup>(1 in <temporary table> on distinct_key where ((1 = `<subquery3>`.`c`))))))))) AS `( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )` from `test`.`t1`
SELECT ( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) ) FROM t1;
( SELECT b FROM t2 WHERE NOT EXISTS ( SELECT c FROM t3 WHERE c = b ) )
1

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

@ -2049,3 +2049,41 @@ a
1000003.0
1.0
End of 5.5 tests
#
# MDEV-13784: query causes seg fault
#
CREATE TABLE t1 (`bug_id` int NOT NULL PRIMARY KEY, `product_id` int NOT NULL);
INSERT INTO t1 VALUES (45199,1184);
CREATE TABLE t2 (`product_id` int NOT NULL,`userid` int NOT NULL, PRIMARY KEY (`product_id`,`userid`));
INSERT INTO t2 VALUES (1184,103),(1184,624),(1184,1577),(1184,1582);
CREATE TABLE t3 (`id` int NOT NULL PRIMARY KEY,`name` varchar(64));
CREATE TABLE t4 ( `userid` int NOT NULL PRIMARY KEY, `login_name` varchar(255));
INSERT INTO t4 VALUES (103,'foo'),(624,'foo'),(1577,'foo'),(1582,'foo');
CREATE TABLE t5 (`id` int NOT NULL PRIMARY KEY, `name` varchar(64));
explain select
(
select login_name from t4 where userId = (
select userid from t2 where product_id = t1.product_id
union
select userid from t2 where product_id = (
select id from t5 where name = (select name from t3 where id = t1.product_id)) limit 1 )
) as x from t1 where (t1.bug_id=45199);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system PRIMARY NULL NULL NULL 1
2 SUBQUERY t4 eq_ref PRIMARY PRIMARY 4 func 1 Using where
3 SUBQUERY t2 ref PRIMARY PRIMARY 4 const 3 Using index
4 UNION t2 ref PRIMARY PRIMARY 4 func 1 Using where; Using index
5 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
6 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
NULL UNION RESULT <union3,4> ALL NULL NULL NULL NULL NULL
select
(
select login_name from t4 where userId = (
select userid from t2 where product_id = t1.product_id
union
select userid from t2 where product_id = (
select id from t5 where name = (select name from t3 where id = t1.product_id)) limit 1 )
) as x from t1 where (t1.bug_id=45199);
x
foo
drop table t1, t2, t3, t4, t5;

4
mysql-test/r/view.result
View File

@ -4633,7 +4633,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
2 DEPENDENT SUBQUERY t4 ALL NULL NULL NULL NULL 2 100.00 Using where
Warnings:
Note 1276 Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
Note 1003 select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or <cache>(isnull(NULL))))) having trigcond(<is_not_null_test>(NULL)))))))
Note 1003 select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or 1))) having trigcond(<is_not_null_test>(NULL)))))))
SELECT * FROM t1, t2
WHERE t2.a NOT IN (SELECT t3.b FROM t3 RIGHT JOIN t4 ON (t4.a = t3.a)
WHERE t4.a >= t1.a);
@ -4649,7 +4649,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
2 DEPENDENT SUBQUERY t4 ALL NULL NULL NULL NULL 2 100.00 Using where
Warnings:
Note 1276 Field or reference 'v1.a' of SELECT #2 was resolved in SELECT #1
Note 1003 select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or <cache>(isnull(NULL))))) having trigcond(<is_not_null_test>(NULL)))))))
Note 1003 select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or 1))) having trigcond(<is_not_null_test>(NULL)))))))
SELECT * FROM v1, t2
WHERE t2.a NOT IN (SELECT t3.b FROM t3 RIGHT JOIN t4 ON (t4.a = t3.a)
WHERE t4.a >= v1.a);

35
mysql-test/t/union.test
View File

@ -1437,3 +1437,38 @@ SET @advertAcctId = 1000003;
select @advertAcctId as a from dual union all select 1.0 from dual;
--echo End of 5.5 tests
--echo #
--echo # MDEV-13784: query causes seg fault
--echo #
CREATE TABLE t1 (`bug_id` int NOT NULL PRIMARY KEY, `product_id` int NOT NULL);
INSERT INTO t1 VALUES (45199,1184);
CREATE TABLE t2 (`product_id` int NOT NULL,`userid` int NOT NULL, PRIMARY KEY (`product_id`,`userid`));
INSERT INTO t2 VALUES (1184,103),(1184,624),(1184,1577),(1184,1582);
CREATE TABLE t3 (`id` int NOT NULL PRIMARY KEY,`name` varchar(64));
CREATE TABLE t4 ( `userid` int NOT NULL PRIMARY KEY, `login_name` varchar(255));
INSERT INTO t4 VALUES (103,'foo'),(624,'foo'),(1577,'foo'),(1582,'foo');
CREATE TABLE t5 (`id` int NOT NULL PRIMARY KEY, `name` varchar(64));
explain select
(
select login_name from t4 where userId = (
select userid from t2 where product_id = t1.product_id
union
select userid from t2 where product_id = (
select id from t5 where name = (select name from t3 where id = t1.product_id)) limit 1 )
) as x from t1 where (t1.bug_id=45199);
select
(
select login_name from t4 where userId = (
select userid from t2 where product_id = t1.product_id
union
select userid from t2 where product_id = (
select id from t5 where name = (select name from t3 where id = t1.product_id)) limit 1 )
) as x from t1 where (t1.bug_id=45199);
drop table t1, t2, t3, t4, t5;

1
sql/sql_lex.cc
View File

@ -3551,6 +3551,7 @@ bool st_select_lex::optimize_unflattened_subqueries(bool const_only)
inner_join->select_options|= SELECT_DESCRIBE;
}
res= inner_join->optimize();
sl->update_used_tables();
sl->update_correlated_cache();
is_correlated_unit|= sl->is_correlated;
inner_join->select_options= save_options;