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MDEV-6868: MariaDB server crash ( select with union and order by with subquery )

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Excluding ORDER BY condition should be done after preparation it (even to catch syntax errors).
This commit is contained in:
unknown 2014-11-15 22:18:33 +01:00
parent 665a7c83b9
commit e7c356f717
3 changed files with 52 additions and 12 deletions
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20
mysql-test/r/union.result
View File

@ -1935,3 +1935,23 @@ id select_type table type possible_keys key key_len ref rows Extra
3 UNION t1 ALL NULL NULL NULL NULL 4
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
drop table t1;
#
# MDEV-6868:MariaDB server crash ( select with union and order by
# with subquery )
#
CREATE TABLE t1 ( id INTEGER, sample_name1 VARCHAR(100), sample_name2 VARCHAR(100), PRIMARY KEY(id) );
INSERT INTO t1 ( id, sample_name1, sample_name2 ) VALUES ( 1, 'aaaa', 'bbbb' ), ( 2, 'cccc', 'dddd' );
(
SELECT sample_name1 AS testname FROM t1
)
UNION
(
SELECT sample_name2 AS testname FROM t1 C ORDER BY (SELECT T.sample_name1 FROM t1 T WHERE T.id = C.id)
)
;
testname
aaaa
cccc
bbbb
dddd
drop table t1;

20
mysql-test/t/union.test
View File

@ -1330,3 +1330,23 @@ create table t1 (a int);
insert t1 values (1),(2),(3),(1);
explain select 1 from dual where exists (select max(a) from t1 group by a union select a+2 from t1);
drop table t1;
--echo #
--echo # MDEV-6868:MariaDB server crash ( select with union and order by
--echo # with subquery )
--echo #
CREATE TABLE t1 ( id INTEGER, sample_name1 VARCHAR(100), sample_name2 VARCHAR(100), PRIMARY KEY(id) );
INSERT INTO t1 ( id, sample_name1, sample_name2 ) VALUES ( 1, 'aaaa', 'bbbb' ), ( 2, 'cccc', 'dddd' );
(
SELECT sample_name1 AS testname FROM t1
)
UNION
(
SELECT sample_name2 AS testname FROM t1 C ORDER BY (SELECT T.sample_name1 FROM t1 T WHERE T.id = C.id)
)
;
drop table t1;

24
sql/sql_union.cc
View File

@ -315,18 +315,6 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
can_skip_order_by= is_union_select && !(sl->braces && sl->explicit_limit);
/*
Remove all references from the select_lex_units to the subqueries that
are inside the ORDER BY clause.
*/
if (can_skip_order_by)
{
for (ORDER *ord= (ORDER *)sl->order_list.first; ord; ord= ord->next)
{
(*ord->item)->walk(&Item::eliminate_subselect_processor, FALSE, NULL);
}
}
saved_error= join->prepare(&sl->ref_pointer_array,
sl->table_list.first,
sl->with_wild,
@ -349,6 +337,18 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
if (saved_error || (saved_error= thd_arg->is_fatal_error))
goto err;
/*
Remove all references from the select_lex_units to the subqueries that
are inside the ORDER BY clause.
*/
if (can_skip_order_by)
{
for (ORDER *ord= (ORDER *)sl->order_list.first; ord; ord= ord->next)
{
(*ord->item)->walk(&Item::eliminate_subselect_processor, FALSE, NULL);
}
}
/*
Use items list of underlaid select for derived tables to preserve
information about fields lengths and exact types