http://www.titov.net Programming / server administration / databases Mon, 22 Jan 2007 16:13:13 +0000 http://backend.userland.com/rss092 en NOW()) ORDER BY username LIMIT 30 NEVER do that. The user in question runs this query on table with 3000+ rows, which means, that SQL server (MySQL in this case) is doing 3000+ date/time additions and will never use any index. If you [...]]]> http://www.titov.net/2005/09/15/date-and-time-addition-and-substraction/ http://www.titov.net/2005/09/15/front-page-extensions-without-mod_frontpage/ http://www.titov.net/2005/09/21/do-not-use-order-by-rand-or-how-to-get-random-rows-from-table/ http://www.titov.net/2005/10/31/how-to-check-if-a-hostname-is-a-valid-registered-nameserver/ http://www.titov.net/2005/12/01/php-forms-spam/ http://www.titov.net/2005/12/31/how-to-restore-reiserfs-partition-from-crashed-disk/ http://www.titov.net/2006/01/02/using-o_largefile-or-o_direct-on-linux/ http://www.titov.net/2006/03/19/how-to-make-site-screenshots-with-linux-server/ http://www.titov.net/2006/03/22/how-to-force-setuid-program-to-make-core-dump/ http://www.titov.net/2006/04/06/how-to-change-maximum-sync-speed-of-linux-software-raid/