DROP TABLE IF EXISTS t1; Warnings: Note 1051 Unknown table 't1' CREATE TABLE t1 ( a varchar(32) character set utf8 collate utf8_bin NOT NULL, b varchar(32) character set utf8 collate utf8_bin NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=utf8; INSERT INTO t1 VALUES ('AAAAAAAAAA','AAAAAAAAAA'), ('AAAAAAAAAB','AAAAAAAAAB '), ('AAAAAAAAAB','AAAAAAAAAB'), ('AAAAAAAAAC','AAAAAAAAAC'), ('AAAAAAAAAD','AAAAAAAAAD'), ('AAAAAAAAAE','AAAAAAAAAE'), ('AAAAAAAAAF','AAAAAAAAAF'), ('AAAAAAAAAG','AAAAAAAAAG'), ('AAAAAAAAAH','AAAAAAAAAH'), ('AAAAAAAAAI','AAAAAAAAAI'), ('AAAAAAAAAJ','AAAAAAAAAJ'), ('AAAAAAAAAK','AAAAAAAAAK'); set tmp_table_size=1024; set session debug="d,raise_error"; SELECT MAX(a) FROM t1 GROUP BY a,b; ERROR 23000: Can't write; duplicate key in table 'tmp_table' set tmp_table_size=default; DROP TABLE t1; # # Bug #50946: fast index creation still seems to copy the table # CREATE TABLE t1 (a INT(100) NOT NULL); INSERT INTO t1 VALUES (1), (0), (2); SET SESSION debug='+d,alter_table_only_index_change'; ALTER TABLE t1 ADD INDEX a(a); SET SESSION debug=DEFAULT; SHOW CREATE TABLE t1; Table Create Table t1 CREATE TABLE `t1` ( `a` int(100) NOT NULL, KEY `a` (`a`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 SELECT * FROM t1; a 0 1 2 DROP TABLE t1; # # Bug#42064: low memory crash when importing hex strings, in Item_hex_string::Item_hex_string # CREATE TABLE t1(a BLOB); SET SESSION debug="+d,bug42064_simulate_oom"; INSERT INTO t1 VALUES(""); Got one of the listed errors SET SESSION debug=DEFAULT; DROP TABLE t1; # # Bug#41660: Sort-index_merge for non-first join table may require # O(#scans) memory # CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (0), (1), (2), (3), (4), (5), (6), (7), (8), (9); CREATE TABLE t2 (a INT, b INT, filler CHAR(100), KEY(a), KEY(b)); INSERT INTO t2 SELECT 1000, 1000, 'filler' FROM t1 A, t1 B, t1 C; INSERT INTO t2 VALUES (1, 1, 'data'); # the example query uses LEFT JOIN only for the sake of being able to # demonstrate the issue with a very small dataset. (left outer join # disables the use of join buffering, so we get the second table # re-scanned for every record in the outer table. if we used inner join, # we would need to have thousands of records and/or more columns in both # tables so that the join buffer is filled and re-scans are triggered). SET SESSION debug = '+d,only_one_Unique_may_be_created'; EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON ( t2.a < 10 OR t2.b < 10 ); id select_type table type possible_keys key key_len ref rows Extra x x x x x x x x x x x x x x x x x x Using sort_union(a,b); Using where SELECT * FROM t1 LEFT JOIN t2 ON ( t2.a < 10 OR t2.b < 10 ); a a b filler 0 1 1 data 1 1 1 data 2 1 1 data 3 1 1 data 4 1 1 data 5 1 1 data 6 1 1 data 7 1 1 data 8 1 1 data 9 1 1 data SET SESSION debug = DEFAULT; DROP TABLE t1, t2; # # End of 5.1 tests #