Comments on: MySQL Performance - eliminating ORDER BY function http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/ Everything about MySQL Performance Tue, 14 Oct 2008 06:41:02 +0000 http://wordpress.org/?v=2.5.1 By: techblog.tilllate.com » Peter Zaitsev of the MySQL Performance Blog speaks in Zurich- http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-197103 techblog.tilllate.com » Peter Zaitsev of the MySQL Performance Blog speaks in Zurich- Sun, 18 Nov 2007 18:29:19 +0000 http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-197103 [...] about MySQL performance optimization. He and his partners of Percona write about topics like eliminating ORDER BY function or Be careful when joining on CONCAT. Peter also held presentations at all Mysql Conferences. In [...] [...] about MySQL performance optimization. He and his partners of Percona write about topics like eliminating ORDER BY function or Be careful when joining on CONCAT. Peter also held presentations at all Mysql Conferences. In [...]

]]> By: peter http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183222 peter Thu, 01 Nov 2007 22:56:34 +0000 http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183222 Why are you surprised you're sorting by FIELD function - of course MySQL can't use Index to do such sort. Why are you surprised you’re sorting by FIELD function - of course MySQL can’t use Index to do such sort.

]]> By: Ladislav http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183141 Ladislav Thu, 01 Nov 2007 18:43:18 +0000 http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183141 Sorry, something's missing ... the problem is the filesort, of course Sorry, something’s missing … the problem is the filesort, of course

]]> By: Ladislav http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183138 Ladislav Thu, 01 Nov 2007 18:40:57 +0000 http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-183138 Slightly off-topic: talking about order by ... trying to find solution for a long time to optimize queries with "order by field" like this: EXPLAIN SELECT id, name FROM table_name WHERE id IN ( 222839, 299872, 301535 ) ORDER BY FIELD( id, 222839, 299872, 301535 ) FROM EXPLAIN: --------------------------------------- select_type SIMPLE table table_name [innodb] type range possible_keys PRIMARY key PRIMARY key_len 4 ref NULL rows 3 Extra Using where; Using filesort Am I plain stupid or is it a bug (in the optimizer) in MySQL ? Slightly off-topic: talking about order by … trying to find solution for a long time to optimize queries with “order by field” like this:

EXPLAIN SELECT id, name
FROM table_name
WHERE id IN ( 222839, 299872, 301535 )
ORDER BY FIELD( id, 222839, 299872, 301535 )

FROM EXPLAIN:
—————————————
select_type SIMPLE
table table_name [innodb]
type range
possible_keys PRIMARY
key PRIMARY
key_len 4
ref NULL
rows 3
Extra Using where; Using filesort

Am I plain stupid or is it a bug (in the optimizer) in MySQL ?

]]> By: Lukas http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-178169 Lukas Wed, 17 Oct 2007 13:04:58 +0000 http://www.mysqlperformanceblog.com/2007/10/17/mysql-performance-eliminating-order-by-function/#comment-178169 So the lesson to learn is if you always apply a specific function on a column, you might as well apply it before the actual insert so that you can leverage the index properly. Or denormalize .. So the lesson to learn is if you always apply a specific function on a column, you might as well apply it before the actual insert so that you can leverage the index properly. Or denormalize ..

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