diff --git a/mysql-test/r/join.result b/mysql-test/r/join.result index b132c8b2e4c..07035a12483 100644 --- a/mysql-test/r/join.result +++ b/mysql-test/r/join.result @@ -391,6 +391,56 @@ i i i 2 NULL 4 2 2 2 drop table t1,t2,t3; +CREATE TABLE t1 (a int, b int default 0, c int default 1); +INSERT INTO t1 (a) VALUES (1),(2),(3),(4),(5),(6),(7),(8); +INSERT INTO t1 (a) SELECT a + 8 FROM t1; +INSERT INTO t1 (a) SELECT a + 16 FROM t1; +CREATE TABLE t2 (a int, d int, e int default 0); +INSERT INTO t2 (a, d) VALUES (1,1),(2,2),(3,3),(4,4); +INSERT INTO t2 (a, d) SELECT a+4, a+4 FROM t2; +INSERT INTO t2 (a, d) SELECT a+8, a+8 FROM t2; +EXPLAIN +SELECT STRAIGHT_JOIN t2.e FROM t1,t2 WHERE t2.d=1 AND t1.b=t2.e +ORDER BY t1.b, t1.c; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ALL NULL NULL NULL NULL 32 Using temporary; Using filesort +1 SIMPLE t2 ALL NULL NULL NULL NULL 16 Using where +SELECT STRAIGHT_JOIN t2.e FROM t1,t2 WHERE t2.d=1 AND t1.b=t2.e +ORDER BY t1.b, t1.c; +e +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +0 +DROP TABLE t1,t2; create table t1 (c int, b int); create table t2 (a int, b int); create table t3 (b int, c int); diff --git a/mysql-test/t/join.test b/mysql-test/t/join.test index 6c9270f76be..4d35989aa9a 100644 --- a/mysql-test/t/join.test +++ b/mysql-test/t/join.test @@ -333,6 +333,30 @@ select t1.i,t2.i,t3.i from t2 natural right join t3,t1 order by t1.i,t2.i,t3.i; select t1.i,t2.i,t3.i from t2 right join t3 on (t2.i=t3.i),t1 order by t1.i,t2.i,t3.i; drop table t1,t2,t3; +# +# Bug #27531: Query performance degredation in 4.1.22 and greater +# +CREATE TABLE t1 (a int, b int default 0, c int default 1); + +INSERT INTO t1 (a) VALUES (1),(2),(3),(4),(5),(6),(7),(8); +INSERT INTO t1 (a) SELECT a + 8 FROM t1; +INSERT INTO t1 (a) SELECT a + 16 FROM t1; + +CREATE TABLE t2 (a int, d int, e int default 0); + +INSERT INTO t2 (a, d) VALUES (1,1),(2,2),(3,3),(4,4); +INSERT INTO t2 (a, d) SELECT a+4, a+4 FROM t2; +INSERT INTO t2 (a, d) SELECT a+8, a+8 FROM t2; + +# should use join cache +EXPLAIN +SELECT STRAIGHT_JOIN t2.e FROM t1,t2 WHERE t2.d=1 AND t1.b=t2.e + ORDER BY t1.b, t1.c; +SELECT STRAIGHT_JOIN t2.e FROM t1,t2 WHERE t2.d=1 AND t1.b=t2.e + ORDER BY t1.b, t1.c; + +DROP TABLE t1,t2; + # End of 4.1 tests # diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 7d7de250dc9..19fa76ee06b 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -6175,11 +6175,14 @@ make_join_readinfo(JOIN *join, ulonglong options) disable join cache because it will change the ordering of the results. Code handles sort table that is at any location (not only first after the const tables) despite the fact that it's currently prohibited. + We must disable join cache if the first non-const table alone is + ordered. If there is a temp table the ordering is done as a last + operation and doesn't prevent join cache usage. */ - if (!ordered_set && - (table == join->sort_by_table && + if (!ordered_set && !join->need_tmp && + ((table == join->sort_by_table && (!join->order || join->skip_sort_order)) || - (join->sort_by_table == (TABLE *) 1 && i != join->const_tables)) + (join->sort_by_table == (TABLE *) 1 && i != join->const_tables))) ordered_set= 1; tab->sorted= sorted;