Slow down in RT w/ strange mysql-slow.log queries

RT Users
1

Noticing lately that RT has really slowed down - its a never ending
battle with shredder stripping spam versus the db filling… ANYWAY…

been getting a lot of these with in mysql-slow.log lately:

Time: 061107 1:55:13

User@Host: rt_user[rt_user] @ localhost []

Query_time: 11 Lock_time: 0 Rows_sent: 1 Rows_examined: 0

SELECT GET_LOCK(‘Apache-Session-b22c6874f84cb8e2ababf7c26a7c7a80’, 3600);

This is after having run rt-clean-sessions.pl and freshly logging in -
the moment this gets logged out the interface displays the ticket -
prior to that its just hanging ‘Transfering data…’

Has anyone got any suggestions ? Its mysql 4.1 on Debian-Sarge…

Thanks!

Adrian

2

Noticing lately that RT has really slowed down - its a never ending
battle with shredder stripping spam versus the db filling… ANYWAY…

been getting a lot of these with in mysql-slow.log lately:

Time: 061107 1:55:13

User@Host: rt_user[rt_user] @ localhost

Query_time: 11 Lock_time: 0 Rows_sent: 1 Rows_examined: 0

SELECT GET_LOCK(‘Apache-Session-b22c6874f84cb8e2ababf7c26a7c7a80’, 3600);

This is after having run rt-clean-sessions.pl and freshly logging in -
the moment this gets logged out the interface displays the ticket -
prior to that its just hanging ‘Transfering data…’

Has anyone got any suggestions ? Its mysql 4.1 on Debian-Sarge…

Thanks!

Adrian

Adrian,

I think the GET_LOCK slow queries is mis-leading. RT’s session
management only allows a user to make one web request at a
time. I have found GET_LOCK simply means that either the user
is try to load 2 different things in RT at once, or the browser
is trying to download css and javascript but the session is
tied up serving a request.

I have found that if you have a lot of custom fields there is
another index that can be applied to the ObjectCustomFieldValues
table that helps with speed. Especially when you are shredding.
Unfortunatley I don’t have that info available to be now.

I would get and run mytop while you are shredding and have
it explain any slow queries you see. Running standalone_httpd
will help separate the real issues from the one request at
a time per session issues.

-Todd

3

Todd Chapman wrote:

Adrian,

I think the GET_LOCK slow queries is mis-leading. RT’s session
management only allows a user to make one web request at a
time. I have found GET_LOCK simply means that either the user
is try to load 2 different things in RT at once, or the browser
is trying to download css and javascript but the session is
tied up serving a request.

Hmm… I definitely only had one request running at the time, so it must
have been CSS or Jscript…

I have found that if you have a lot of custom fields there is
another index that can be applied to the ObjectCustomFieldValues
table that helps with speed. Especially when you are shredding.
Unfortunatley I don’t have that info available to be now.

This might help a lot - I do use a few CF’s and almost every ticket
utilises at least 3 or 4 of them. If you could dig up the index’s that
would be great.

I would get and run mytop while you are shredding and have
it explain any slow queries you see. Running standalone_httpd
will help separate the real issues from the one request at
a time per session issues.

I’ll give this a go later on tonight and see what it yields when the
server isn’t quite so busy :slight_smile:

-Todd

Adrian Carter
Network Manager
Leading Edge Internet

Web http://www.lei.net.au http://support.lei.net.au
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E-mail cartera@lei.net.au