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Re: GROUP BY not properly observed with join cache
Test case:
CREATE TABLE `CC` (
`pk` int(11) NOT NULL AUTO_INCREMENT,
`col_int_key` int(11) NOT NULL,
`col_varchar_key` varchar(1) NOT NULL,
PRIMARY KEY (`pk`),
KEY `col_int_key` (`col_int_key`),
KEY `col_varchar_key` (`col_varchar_key`,`col_int_key`)
) ENGINE=MyISAM AUTO_INCREMENT=30 DEFAULT CHARSET=latin1;
INSERT INTO `CC` VALUES (10,8,'v');
INSERT INTO `CC` VALUES (11,8,'f');
INSERT INTO `CC` VALUES (12,5,'v');
INSERT INTO `CC` VALUES (13,8,'s');
INSERT INTO `CC` VALUES (14,8,'a');
INSERT INTO `CC` VALUES (15,6,'p');
INSERT INTO `CC` VALUES (16,7,'z');
INSERT INTO `CC` VALUES (17,2,'a');
INSERT INTO `CC` VALUES (18,5,'h');
INSERT INTO `CC` VALUES (19,7,'h');
INSERT INTO `CC` VALUES (20,2,'v');
INSERT INTO `CC` VALUES (21,9,'v');
INSERT INTO `CC` VALUES (22,142,'b');
INSERT INTO `CC` VALUES (23,3,'y');
INSERT INTO `CC` VALUES (24,0,'v');
INSERT INTO `CC` VALUES (25,3,'m');
INSERT INTO `CC` VALUES (26,5,'z');
INSERT INTO `CC` VALUES (27,9,'n');
INSERT INTO `CC` VALUES (28,1,'d');
INSERT INTO `CC` VALUES (29,107,'a');
CREATE TABLE `C` (
`pk` int(11) NOT NULL AUTO_INCREMENT,
`col_int_key` int(11) NOT NULL,
`col_varchar_key` varchar(1) NOT NULL,
PRIMARY KEY (`pk`),
KEY `col_int_key` (`col_int_key`),
KEY `col_varchar_key` (`col_varchar_key`,`col_int_key`)
) ENGINE=MyISAM AUTO_INCREMENT=21 DEFAULT CHARSET=latin1;
INSERT INTO `C` VALUES (1,9,'x');
INSERT INTO `C` VALUES (2,5,'g');
INSERT INTO `C` VALUES (3,1,'o');
INSERT INTO `C` VALUES (4,0,'g');
INSERT INTO `C` VALUES (5,1,'v');
INSERT INTO `C` VALUES (6,190,'m');
INSERT INTO `C` VALUES (7,6,'x');
INSERT INTO `C` VALUES (8,3,'c');
INSERT INTO `C` VALUES (9,4,'z');
INSERT INTO `C` VALUES (10,3,'i');
INSERT INTO `C` VALUES (11,186,'x');
INSERT INTO `C` VALUES (12,1,'g');
INSERT INTO `C` VALUES (13,8,'q');
INSERT INTO `C` VALUES (14,226,'m');
INSERT INTO `C` VALUES (15,133,'p');
INSERT INTO `C` VALUES (16,6,'e');
INSERT INTO `C` VALUES (17,3,'t');
INSERT INTO `C` VALUES (18,8,'j');
INSERT INTO `C` VALUES (19,5,'h');
INSERT INTO `C` VALUES (20,7,'w');
SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
EXPLAIN SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
SET SESSION join_cache_level = 4;
SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
EXPLAIN SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
SET SESSION optimizer_switch='join_cache_hashed=off';
SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
EXPLAIN SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
SET SESSION optimizer_switch='join_cache_bka=off';
SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
EXPLAIN SELECT table2 .`col_varchar_key` field1 FROM CC table1 LEFT JOIN CC table2 STRAIGHT_JOIN C table3 ON table3 .`col_varchar_key` <> table2 .`col_varchar_key` ON table3 .`pk` = table2 .`col_int_key` WHERE table1 .`col_varchar_key` = table3 .`col_varchar_key` GROUP BY field1 ORDER BY table1 .`pk` ;
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LPexportBug664508.xml