[rt-users] Unusually long queries when calling GET_LOCK with MySQL

[dustin at cnw.com]

Hello,

I've been watching my slow queries log and came across some really long
queries, which happen at the same time one of our RT users has troubles
accessing RT. This happens when the one user attempts any action in RT. It
is just happening for this one user, and the problem goes away if that
user starts a new session.

The only other things in my slow query log look like ACL checks similar to 
the ones listed at the bottom of this email.

These seemed a little bit long and I was wondering if anyone could give 
me some pointers of how to go about troubleshooting this.

RT 3.0.10, Perl 5.8.2 (ick), MySQL 4.0.16, FreeBSD 5.2-CURRENT

Thanks,
Dustin

-------------------------

# Time: 040826 10:32:15
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 1294  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# Time: 040826 10:21:31
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 1185  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# Time: 040826 10:27:02
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 1500  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# Time: 040826 10:16:05
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 861  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# Time: 040826 10:38:13
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 1465  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 516  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 423  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
SELECT GET_LOCK('Apache-Session-ae38b18e1826f57e5ac417069b4dd822', 3600);

-------------------------

# Time: 040826 13:13:34
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 3  Lock_time: 0  Rows_sent: 17  Rows_examined: 71
SELECT DISTINCT main.* FROM ( Groups main LEFT JOIN Principals as 
Principals_2  ON  ( main.id = Principals_2.id)), ACL ACL_1  WHERE 
((ACL_1.RightName = 'OwnTicket')OR(ACL_1.RightName = 'SuperUser')) AND 
((Principals_2.Disabled = '0')) AND 
          ( (    ACL_1.PrincipalId = main.id
             AND ACL_1.PrincipalType = 'Group'
             AND (   main.Domain = 'SystemInternal'
                  OR main.Domain = 'UserDefined'
                  OR main.Domain = 'ACLEquivalence'))
            OR ( ( (main.Domain = 'RT::Queue-Role' AND main.Instance = 4)  
OR ( main.Domain = 'RT::Ticket-Role' AND main.Instance = 331092)  )  AND 
main.Type = ACL_1.PrincipalType) )
         AND (ACL_1.ObjectType = 'RT::System' OR  (ACL_1.ObjectType = 
'RT::Queue' AND ACL_1.ObjectId = 4) ) ORDER BY main.Name ASC;