Hello,
Indeed, when I use {put,front,putdatetime}, no filesort is used. But the query is still very slow.
It takes about 2 seconds. And again, mysql prefers not to use your key, but I can force that of course.
I did an ANALYZE TABLE but that didn't change things, it might have sped up the other queries on the table.
Probably this query can't be sped up because of the functions I use.
Is there another thing I can try to speed the query up?
And another question, is it normal that even when not using the cache (always executing RESET QUERY CACHE; before the query), the query sometimes only takes 0.33 seconds, and at other times the query takes 22 seconds? Is this something everyone here experiences? Or is there something wrong with my configuration?
Regards, Dirk.
Jocelyn Fournier wrote:
Hi,
I would say for this one you need an index on (put, front, putdatetime) to get rid of the filesorting. Note that because you're transforming the putdatetime column with functions, MySQL will not be able to use index infos of putdatetime. So it will use put and front index information to find the result, and putdatetime to order the result. If you add topcategory in your query, you will see MySQL will use the index (put, front, topcategory, putdatetime) without filesorting.
Regards,
Jocelyn Fournier
www.presence-pc.com
----- Original Message ----- From: "Dirk Schippers" <[EMAIL PROTECTED]>
To: "Jocelyn Fournier" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Sunday, September 19, 2004 11:55 AM
Subject: Re: Query takes terribly long
cacheHello,
Sorry to bother you again, but now I have the following, bit more complicated query on the same table: SELECT id FROM story WHERE MONTH(putdatetime) = MONTH('2004-09-19') AND DAYOFMONTH(putdatetime) = DAYOFMONTH('2004-09-19') AND YEAR(putdatetime) < YEAR('2004-09-19') AND put=1 AND front=1 ORDER BY putdatetime DESC LIMIT 0,30
The date is not Now() because the cache won't optimize the query then and now the cache can use the same query all day. But EXPLAIN says that the same index (yours) is used but he still uses a filesort, on almost all the rows of the table (18775). You can imagine how slow this query is.
Is there a way to improve this one?
Thanks and sorry about the lot of messages you are receiving, but I'm learning a lot here!
Dirk.
Jocelyn Fournier wrote:
Are you sure this not because your query is cached by the MySQL query
now ? (try RESET QUERY CACHE before testing your query to be sure)
Regards,
Jocelyn Fournier
www.presence-pc.com
----- Original Message ----- From: "Dirk Schippers" <[EMAIL PROTECTED]>
To: "Jocelyn Fournier" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, September 18, 2004 11:53 PM
Subject: Re: Query takes terribly long
--
Schippers Dirk Zaakvoerder Frixx-iT http://www.frixx-it.com ------------------------------------------------------------------------ Bezoek ook http://www.verhalensite.com voor uw literaire tekortkomingen.
