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MDEV-24910 Crash with SELECT that uses table value constructor as a subselect

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This bug caused crashes of the server when processing queries with table
value constructors (TVC) that contained subqueries and were used itself as
subselects. For such TVCs the following transformation is applied at the
prepare stage:
  VALUES (v1), ... (vn) => SELECT * FROM (VALUES (v1), ... (vn)) tvc_x.
This transformation allows to reduce the problem of evaluation of TVCs used
as subselects to the problem of evaluation of regular subselects.
The transformation is implemented in the wrap_tvc(). The code the function
to mimic the behaviour of the parser when processing the result of the
transformation. However this imitation was not free of some flaws. First
the function called the method exclude() that completely destroyed the
select tree structures below the transformed TVC. Second the function
used the procedure mysql_new_select to create st_select_lex nodes for
both wrapping select of the transformation and TVC. This also led to
constructing of invalid select tree structures.
The patch actually re-engineers the code of wrap_tvc().

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev
2021-02-24 13:51:47 -08:00
parent 13f0e1e139
commit bf6484e7bb
6 changed files with 233 additions and 33 deletions
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110
mysql-test/main/table_value_constr.result
View File

@ -748,7 +748,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
3 MATERIALIZED <derived2> ALL NULL NULL NULL NULL 2 100.00
2 DERIVED NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` semi join ((values (1)) `tvc_0`) where 1
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` semi join ((values (1)) `tvc_0`) where 1
explain extended select * from t1
where a in (select * from (values (1)) as tvc_0);
id select_type table type possible_keys key key_len ref rows filtered Extra
@ -983,7 +983,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
3 MATERIALIZED <derived2> ALL NULL NULL NULL NULL 2 100.00
2 DERIVED NULL NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` semi join ((values (1),(2)) `tvc_0`) where 1
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` semi join ((values (1),(2)) `tvc_0`) where 1
explain extended select * from t1
where a = any (select * from (values (1),(2)) as tvc_0);
id select_type table type possible_keys key key_len ref rows filtered Extra
@ -2775,4 +2775,110 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
2 SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where
drop table t1;
#
# MDEV-24910: TVC containing subquery used as a subselect
#
create table t1 (a int) engine=myisam;
insert into t1 values (3), (7), (1);
create table t2 (b int) engine=myisam;
insert into t2 values (1), (2);
select (values ((select 2))) from t2;
(values ((select 2)))
2
2
explain select (values ((select 2))) from t2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2
4 SUBQUERY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
Warnings:
Note 1249 Select 3 was reduced during optimization
prepare stmt from "select (values ((select 2))) from t2";
execute stmt;
(values ((select 2)))
2
2
execute stmt;
(values ((select 2)))
2
2
deallocate prepare stmt;
select (values ((select * from t1 where a > 10))) from t2;
(values ((select * from t1 where a > 10)))
NULL
NULL
explain select (values ((select * from t1 where a > 10))) from t2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2
4 SUBQUERY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
3 SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where
prepare stmt from "select (values ((select * from t1 where a > 10))) from t2";
execute stmt;
(values ((select * from t1 where a > 10)))
NULL
NULL
execute stmt;
(values ((select * from t1 where a > 10)))
NULL
NULL
deallocate prepare stmt;
create table t3 (a int);
insert into t3 values
(3), (7), (7), (1), (3), (9), (7), (9), (8), (7), (8);
create view v1 as select count(a) as c from t3 group by a;
select
(values ((select * from t3 where a in (select * from v1))));
(values ((select * from t3 where a in (select * from v1))))
1
explain select
(values ((select * from t3 where a in (select * from v1))));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
6 SUBQUERY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
3 SUBQUERY t3 ALL NULL NULL NULL NULL 11
3 SUBQUERY <subquery4> eq_ref distinct_key distinct_key 8 func 1 Using where
4 MATERIALIZED <derived5> ALL NULL NULL NULL NULL 11
5 DERIVED t3 ALL NULL NULL NULL NULL 11 Using temporary; Using filesort
prepare stmt from "select
(values ((select * from t3 where a in (select * from v1))))";
execute stmt;
(values ((select * from t3 where a in (select * from v1))))
1
execute stmt;
(values ((select * from t3 where a in (select * from v1))))
1
deallocate prepare stmt;
select
(values ((select * from t3
where a > 10 and a in (select * from v1))));
(values ((select * from t3
where a > 10 and a in (select * from v1))))
NULL
explain select
(values ((select * from t3
where a > 10 and a in (select * from v1))));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
6 SUBQUERY <derived2> ALL NULL NULL NULL NULL 2
2 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
3 SUBQUERY t3 ALL NULL NULL NULL NULL 11 Using where
3 SUBQUERY <subquery4> eq_ref distinct_key distinct_key 8 func 1 Using where
4 MATERIALIZED <derived5> ALL NULL NULL NULL NULL 11
5 DERIVED t3 ALL NULL NULL NULL NULL 11 Using temporary; Using filesort
prepare stmt from "select
(values ((select * from t3
where a > 10 and a in (select * from v1))))";
execute stmt;
(values ((select * from t3
where a > 10 and a in (select * from v1))))
NULL
execute stmt;
(values ((select * from t3
where a > 10 and a in (select * from v1))))
NULL
deallocate prepare stmt;
drop view v1;
drop table t1,t2,t3;
End of 10.3 tests