[Tickets #6633] Performance query MYSQL

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Ticket URL: http://bugs.horde.org/ticket/6633
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 Ticket             | 6633
 Created By         | marco.curradi at asf.toscana.it
 Summary            | Performance query MYSQL
 Queue              | Kronolith
 Version            | HEAD
 Type               | Bug
 State              | Unconfirmed
 Priority           | 1. Low
 Milestone          |
 Patch              |
 Owners             |
+New Attachment     | horde_mysql.pdf
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marco.curradi at asf.toscana.it (2008-04-22 04:58) wrote:

Hi we have some problem with a query:

SELECT c.datatree_id, c.datatree_name FROM horde_datatree c LEFT JOIN
horde_datatree_attributes a1 ON a1.datatree_id = c.datatree_id WHERE
c.group_uid = 'horde.shares.kronolith' AND ( a1.attribute_name = 'owner'
AND a1.attribute_value = 'marco.curradi' ) GROUP BY c.datatree_id,
c.datatree_name, c.datatree_order ORDER BY c.datatree_order,
c.datatree_name, c.datatree_id;

This query use the CPU at the 100%.

We have this problem only the users connection are about 20-30 or more.
This query use the disk  and if running 3-4 this query the process of
Mysql use the 100% of CPU.
This query find 1 record but move 15000 record on temp (see the
attachment).
I think the problem is the ORDER BY. Is necessary to use ORDER BY ?

thanks for your help