Thanks Nicola,
I have just tried this and it's not made an difference to the
performance. I found your previous emails on this subject so tried the same
EXPLAIN and it's pretty quick.
mysql> explain SELECT DISTINCT main.* FROM Users main JOIN Principals
Principals_1 ON
-> ( Principals_1.id = main.id ) JOIN CachedGroupMembers
CachedGroupMembers_2 ON
-> ( CachedGroupMembers_2.MemberId = Principals_1.id ) JOIN Groups Groups_3
ON (
-> Groups_3.id = CachedGroupMembers_2.GroupId ) WHERE
(Principals_1.Disabled =
-> '0') AND (Principals_1.id != '1') AND (Principals_1.PrincipalType =
'User') AND
-> ((Groups_3.Domain = 'RT::Queue-Role' AND Groups_3.Instance = '3') OR
-> (Groups_3.Domain = 'RT::System-Role')) AND (Groups_3.Type = 'AdminCc')
ORDER
-> BY main.Name ASC;
+----+-------------+----------------------+--------+----------------------------------------------+------------+---------+------------------------------------+------+-----------------------------------------------------------+
| id | select_type | table | type | possible_keys
| key | key_len | ref |
rows | Extra |
+----+-------------+----------------------+--------+----------------------------------------------+------------+---------+------------------------------------+------+-----------------------------------------------------------+
| 1 | SIMPLE | Groups_3 | range | PRIMARY,Groups1,Groups2
| Groups1 | 139 | NULL |
5 | Using where; Using index; Using temporary; Using filesort |
| 1 | SIMPLE | CachedGroupMembers_2 | ref |
DisGrouMem,CachedGroupMembers3,SHREDDER_CGM1 | DisGrouMem | 5 |
rtdb.Groups_3.id | 1 | Using where; Using index
|
| 1 | SIMPLE | Principals_1 | eq_ref | PRIMARY
| PRIMARY | 4 | rtdb.CachedGroupMembers_2.MemberId |
1 | Using where |
| 1 | SIMPLE | main | eq_ref | PRIMARY
| PRIMARY | 4 | rtdb.Principals_1.id |
1 | Using where |
+----+-------------+----------------------+--------+----------------------------------------------+------------+---------+------------------------------------+------+-----------------------------------------------------------+
4 rows in set (0.00 sec)
From: Foggi, Nicola [mailto:nfo...@depaul.edu]
Sent: 18 August 2010 15:02
To: Alex Young; rt-users@lists.bestpractical.com
Subject: RE: [rt-users] Slow MySQL after upgrade from 3.8.6 to 3.8.8
I had the same problem and ended up dropping the Groups2 index and performance
went back to "normal"
Nicola
-----Original Message-----
From: rt-users-boun...@lists.bestpractical.com on behalf of Alex Young
Sent: Wed 8/18/2010 6:07 AM
To: rt-users@lists.bestpractical.com
Subject: [rt-users] Slow MySQL after upgrade from 3.8.6 to 3.8.8
Hi,
Since upgrading from 3.8.6 to 3.8.8 our RT system has
been very slow to return any pages containing ticket data such as the
home page, searches and tickets themselves.
I enabled the MySQL slow running query log and this was at the top of
the list:
mysqldumpslow -t 10 /var/log/mysql/mysql-slow.log
Reading mysql slow query log from /var/log/mysql/mysql-slow.log
Count: 47 Time=10.12s (475s) Lock=0.00s (0s) Rows=1.0 (47),
rtuser[rtus...@*************
SELECT GET_LOCK('S', N)
Any ideas?
Thanks.
RT Training in Washington DC, USA on Oct 25 & 26 2010
Last one this year -- Learn how to get the most out of RT!
