[EMAIL PROTECTED] wrote on 08/01/2005 09:13:46 AM:
> I have this query which gets executed often, but when I saw this today I
> panicked. Any suggestions to why this took so long?
>
> mysql> SELECT t2.id, t2.bdate, t2.level FROM bvolset AS t1 JOIN bvolset
AS
> t2 ON t2.bdate bdate DESC LIMIT 1;
>
> Empty set (22.82 sec)
>
> here is the schema and data:
>
> CREATE TABLE bvolset (
> id int(11) NOT NULL auto_increment,
> bdate datetime default NULL,
> level int(11) NOT NULL default '0',
> PRIMARY KEY (id),
> UNIQUE KEY bdate (bdate),
> KEY level (level)
> ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
>
>
>
> INSERT INTO `bvolset` VALUES (1,'2005-07-05 00:00:00',0),
> (15,'2005-01-01 00:00:00',3),(16,'2005-01-02 00:00:00',4),
> (17,'2005-01-03 00:00:00',3),(18,'2005-01-04 00:00:00',2),
> (19,'2005-01-05 00:00:00',3),(20,'2005-01-06 00:00:00',4),
> (21,'2005-01-07 00:00:00',3),(22,'2005-01-08 00:00:00',1),
> (23,'2005-01-09 00:00:00',3),(24,'2005-01-10 00:00:00',4),
> (25,'2005-01-11 00:00:00',3),(26,'2005-01-12 00:00:00',2),
> (27,'2005-01-13 00:00:00',3),(28,'2005-01-14 00:00:00',4),
> (29,'2005-01-15 00:00:00',3),(30,'2005-01-16 00:00:00',0),
> (31,'2005-01-17 00:00:00',3),(32,'2005-01-18 00:00:00',4),
> (33,'2005-01-19 00:00:00',3),(34,'2005-01-20 00:00:00',2),
> (35,'2005-01-21 00:00:00',3),(36,'2005-01-22 00:00:00',4),
> (37,'2005-01-23 00:00:00',3),(38,'2005-01-24 00:00:00',1),
> (39,'2005-01-25 00:00:00',3),(40,'2005-01-26 00:00:00',4),
> (41,'2005-01-27 00:00:00',3),(42,'2005-01-28 00:00:00',2),
> (43,'2005-01-29 00:00:00',3),(44,'2005-01-30 00:00:00',4),
> (45,'2005-01-31 00:00:00',3),(46,'2004-12-31 00:00:00',0),
> (47,'2005-07-07 12:12:59',0),(48,'2005-07-07 12:21:33',0),
> (49,'2005-07-07 12:24:42',0),(50,'2005-07-07 12:26:20',0),
> (51,'2005-07-07 12:27:34',0),(52,'2005-07-07 12:28:21',0),
> (53,'2005-07-07 12:29:00',0),(54,'2005-07-07 14:05:09',0),
> (55,'2005-07-07 14:20:02',0),(56,'2005-07-07 14:20:33',0),
> (57,'2005-07-07 14:22:03',0),(58,'2005-07-07 14:22:09',0),
> (59,'2005-07-07 14:22:21',0),(60,'2005-07-07 14:22:28',0),
> (61,'2005-07-07 14:25:24',0),(62,'2005-07-07 14:25:42',0),
> (63,'2005-07-07 16:42:52',0),(64,'2005-07-07 16:43:09',0),
> (65,'2005-07-07 16:43:26',0),(66,'2005-07-07 16:43:34',0),
> (67,'2005-07-07 16:43:51',0),(68,'2005-07-07 16:44:59',0),
> (69,'2005-07-07 16:47:25',0),(70,'2005-07-07 16:48:26',0),
> (71,'2005-07-07 16:51:10',0),(72,'2005-07-07 16:52:37',0),
> (73,'2005-07-07 16:57:39',0),(74,'2005-07-07 16:58:47',0),
> (75,'2005-07-07 17:00:43',0),(76,'2005-07-07 17:00:53',0),
> (77,'2005-07-07 17:12:07',0),(78,'2005-07-07 17:53:46',0),
> (79,'2005-07-07 18:03:20',0),(80,'2005-07-07 18:05:19',0),
> (81,'2005-07-08 00:13:26',0),(82,'2005-07-08 01:05:06',0),
> (83,'2005-07-08 01:06:14',0),(84,'2005-07-08 01:06:32',0),
> (85,'2005-07-08 01:09:36',0),(86,'2005-07-08 01:11:51',0),
> (87,'2005-07-08 01:12:11',0),(88,'2005-07-08 01:12:19',0),
> (89,'2005-07-08 09:54:34',0),(90,'2005-07-08 09:59:11',0),
> (91,'2005-07-08 09:59:55',0),(92,'2005-07-08 10:26:02',0),
> (93,'2005-07-08 10:28:11',0),(94,'2005-07-08 10:28:25',0),
> (95,'2005-07-08 10:35:19',0),(96,'2005-07-08 10:36:16',0),
> (97,'2005-07-08 10:36:37',0),(98,'2005-07-08 10:38:07',0),
> (99,'2005-07-08 10:38:59',0),(100,'2005-07-08 10:39:24',0),
> (101,'2005-07-08 10:40:34',0),(102,'2005-07-08 10:42:24',0),
> (103,'2005-07-08 10:42:51',0),(104,'2005-07-08 10:43:37',0),
> (105,'2005-07-08 10:43:50',0),(106,'2005-07-08 10:44:08',0),
> (107,'2005-07-08 11:45:37',0),(108,'2005-07-08 11:45:44',0),
> (109,'2005-07-08 11:55:15',0),(110,'2005-07-08 11:57:01',0),
> (111,'2005-07-08 11:57:17',0),(112,'2005-07-08 11:57:27',0),
> (113,'2005-07-08 11:57:34',0),(114,'2005-07-08 11:57:43',0),
> (115,'2005-07-08 11:58:03',0),(116,'2005-07-08 11:58:36',0),
> (117,'2005-07-08 11:59:57',0),(118,'2005-07-08 12:00:24',0),
> (119,'2005-07-08 12:10:28',0),(120,'2005-07-08 13:56:29',0),
> (121,'2005-07-08 13:56:35',0),(122,'2005-07-08 13:56:43',0),
> (123,'2005-07-08 13:56:47',0),(124,'2005-07-08 13:57:13',0),
> (125,'2005-07-08 13:57:54',0),(126,'2005-07-08 13:58:35',0),
> (127,'2005-07-09 12:25:41',0),(128,'2005-07-09 12:26:42',0),
> (129,'2005-07-09 12:34:01',0),(130,'2005-07-09 12:35:11',0),
> (131,'2005-07-09 12:38:37',0),(132,'2005-07-09 12:46:47',0),
> (133,'2005-07-09 12:48:15',0),(134,'2005-07-09 12:49:48',0),
> (135,'2005-07-09 12:57:10',0),(136,'2005-07-09 13:17:12',0),
> (137,'2005-07-09 14:22:30',0),(138,'2005-07-09 14:23:11',0),
> (139,'2005-07-09 14:23:41',0),(140,'2005-07-09 19:11:40',0),
> (141,'2005-07-09 19:16:17',0),(142,'2005-07-09 19:17:45',0),
> (143,'2005-07-09 19:19:12',0),(144,'2005-07-10 01:06:42',0),
> (145,'2005-07-10 01:07:19',0),(146,'2005-07-10 01:07:39',0),
> (147,'2005-07-10 01:10:06',0),(148,'2005-07-10 02:00:46',0),
> (149,'2005-07-10 02:06:58',0),(150,'2005-07-10 02:08:19',0),
> (151,'2005-07-10 02:08:41',0),(152,'2005-07-10 02:09:50',0),
> (153,'2005-07-10 02:43:35',0),(154,