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Fixed mdev-6706 Wrong result (missing rows)

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with joins, SQ, ORDER BY, semijoin=on

A bug in get_sort_by_table() could mislead the function
setup_semijoin_dups_elimination(). As a result the optimizer
could produce invalid execution plans for queries with ORDER BY
and subquery predicates that could be converted to semi-joins.
This commit is contained in:
Igor Babaev 2018-01-12 00:14:40 -08:00
parent 6293e3bbcf
commit abc123391f
3 changed files with 85 additions and 0 deletions
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46
mysql-test/r/order_by.result
View File

@ -2061,4 +2061,50 @@ ORDER BY NULL, @a0 := 3, @a1 := 3, @a2 := 3, @a3 := 3, @a4 := 3,
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1
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#
# mdev-6706: semi-join with duplicate weedout + ORDER BY
#
CREATE TABLE t1 (f1 VARCHAR(3)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('foo');
CREATE TABLE t2 (f2 VARCHAR(3)) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('bar'),('baz');
CREATE TABLE t3
(i3_key INT, f3_key VARCHAR(3), f3 VARCHAR(3), KEY(f3_key,i3_key))
ENGINE=MyISAM;
INSERT INTO t3 VALUES (0,'qux','qux'),(8,'bar','bar');
SELECT CONCAT( f1, f2 ) AS field FROM t1, t2
WHERE f1 = ANY ( SELECT f1
FROM t1
LEFT JOIN ( t3 AS t3a, t3 AS t3b )
ON ( t3b.f3_key = t3a.f3 )
WHERE t3a.f3 < f1 OR t3b.f3 != f1 );
field
foobar
foobaz
SELECT CONCAT( f1, f2 ) AS field FROM t1, t2
WHERE f1 = ANY ( SELECT f1
FROM t1
LEFT JOIN ( t3 AS t3a, t3 AS t3b )
ON ( t3b.f3_key = t3a.f3 )
WHERE t3a.f3 < f1 OR t3b.f3 != f1 )
ORDER BY field;
field
foobar
foobaz
EXPLAIN EXTENDED SELECT CONCAT( f1, f2 ) AS field FROM t1, t2
WHERE f1 = ANY ( SELECT f1
FROM t1
LEFT JOIN ( t3 AS t3a, t3 AS t3b )
ON ( t3b.f3_key = t3a.f3 )
WHERE t3a.f3 < f1 OR t3b.f3 != f1 )
ORDER BY field;
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00 Using temporary; Using filesort
1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00
1 PRIMARY t3a ALL NULL NULL NULL NULL 2 100.00 Using where; Start temporary
1 PRIMARY t3b ref f3_key f3_key 6 test.t3a.f3 1 100.00 Using where; End temporary
Warnings:
Note 1003 select concat('foo',`test`.`t2`.`f2`) AS `field` from `test`.`t2` semi join ((`test`.`t3` `t3a` join `test`.`t3` `t3b`)) where ((`test`.`t3a`.`f3` < 'foo') or (`test`.`t3b`.`f3` <> 'foo')) order by concat('foo',`test`.`t2`.`f2`)
DROP TABLE t1,t2,t3;
End of 5.5 tests

38
mysql-test/t/order_by.test
View File

@ -1756,6 +1756,44 @@ UNION
ORDER BY NULL, @a0 := 3, @a1 := 3, @a2 := 3, @a3 := 3, @a4 := 3,
@a5 := 3, @a6 := 3, @a7 := 3, @a8 := 3, @a9 := 3, @a10 := 3 );
--echo #
--echo # mdev-6706: semi-join with duplicate weedout + ORDER BY
--echo #
CREATE TABLE t1 (f1 VARCHAR(3)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('foo');
CREATE TABLE t2 (f2 VARCHAR(3)) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('bar'),('baz');
CREATE TABLE t3
(i3_key INT, f3_key VARCHAR(3), f3 VARCHAR(3), KEY(f3_key,i3_key))
ENGINE=MyISAM;
INSERT INTO t3 VALUES (0,'qux','qux'),(8,'bar','bar');
let $q1=
SELECT CONCAT( f1, f2 ) AS field FROM t1, t2
WHERE f1 = ANY ( SELECT f1
FROM t1
LEFT JOIN ( t3 AS t3a, t3 AS t3b )
ON ( t3b.f3_key = t3a.f3 )
WHERE t3a.f3 < f1 OR t3b.f3 != f1 );
let $q2=
SELECT CONCAT( f1, f2 ) AS field FROM t1, t2
WHERE f1 = ANY ( SELECT f1
FROM t1
LEFT JOIN ( t3 AS t3a, t3 AS t3b )
ON ( t3b.f3_key = t3a.f3 )
WHERE t3a.f3 < f1 OR t3b.f3 != f1 )
ORDER BY field;
eval $q1;
eval $q2;
eval EXPLAIN EXTENDED $q2;
DROP TABLE t1,t2,t3;
--echo End of 5.5 tests

1
sql/sql_select.cc
View File

@ -21159,6 +21159,7 @@ get_sort_by_table(ORDER *a,ORDER *b, List<TABLE_LIST> &tables,
if (!map || (map & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT)))
DBUG_RETURN(0);
map&= ~const_tables;
while ((table= ti++) && !(map & table->table->map)) ;
if (map != table->table->map)
DBUG_RETURN(0); // More than one table