# # Bug 12365385 STRAIGHT_JOIN QUERY QUICKLY EXHAUSTS SYSTEM+VIRT. # MEMORY LEADING TO SYSTEM CRASH # CREATE TABLE ten (a INTEGER); INSERT INTO ten VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); CREATE TABLE hundred (a INTEGER); INSERT INTO hundred SELECT a1.a + 10 * a2.a FROM ten a1, ten a2; CREATE TABLE thousand (a INTEGER); INSERT INTO thousand SELECT a1.a + 10 * a2.a + 100 * a3.a FROM ten a1, ten a2, ten a3; CREATE TABLE t1 ( pk INTEGER NOT NULL, i1 INTEGER NOT NULL, c1 VARCHAR(10) NOT NULL, PRIMARY KEY (pk) ); INSERT INTO t1 SELECT a, 1, 'MySQL' FROM thousand; CREATE TABLE t2 ( pk INTEGER NOT NULL, c1 VARCHAR(10) NOT NULL, c2 varchar(10) NOT NULL, PRIMARY KEY (pk) ); INSERT INTO t2 SELECT a, 'MySQL', 'MySQL' FROM ten; CREATE TABLE t3 ( pk INTEGER NOT NULL, c1 VARCHAR(10) NOT NULL, PRIMARY KEY (pk) ); INSERT INTO t3 SELECT a, 'MySQL' FROM hundred; CREATE TABLE t4 ( pk int(11) NOT NULL, c1_key varchar(10) CHARACTER SET utf8 NOT NULL, c2 varchar(10) NOT NULL, c3 varchar(10) NOT NULL, PRIMARY KEY (pk), KEY k1 (c1_key) ); CREATE TABLE t5 ( pk INTEGER NOT NULL, c1 VARCHAR(10) NOT NULL, PRIMARY KEY (pk) ); INSERT INTO t5 SELECT a, 'MySQL' FROM ten; set optimizer_switch=`mrr=on,mrr_cost_based=off`; EXPLAIN SELECT STRAIGHT_JOIN * FROM (t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT OUTER JOIN t4 ON t3.c1 <= t4.c1_key) ON t2.c1 = t4.c3) ON t1.c1 = t4.c2) RIGHT OUTER JOIN t5 ON t2.c2 <= t5.c1 WHERE t1.i1 = 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t5 ALL NULL NULL NULL NULL 10 NULL 1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 Using where; Using join buffer (Block Nested Loop) 1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (Block Nested Loop) 1 SIMPLE t3 ALL NULL NULL NULL NULL 100 Using join buffer (Block Nested Loop) 1 SIMPLE t4 ALL k1 NULL NULL NULL 0 Range checked for each record (index map: 0x2) SELECT STRAIGHT_JOIN * FROM (t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT OUTER JOIN t4 ON t3.c1 <= t4.c1_key) ON t2.c1 = t4.c3) ON t1.c1 = t4.c2) RIGHT OUTER JOIN t5 ON t2.c2 <= t5.c1 WHERE t1.i1 = 1; pk i1 c1 pk c1 c2 pk c1 pk c1_key c2 c3 pk c1 DROP TABLE ten, hundred, thousand; DROP TABLE t1, t2, t3, t4, t5;