[rt-users] Please help - rt4 slow after upgrade

[Chris Hall]

Seems after watching a few days this is still an issue.  It seems completely
random.. some pages just... take awhile to load for some reason.  15 - 20
seconds, and then you can blast through a few pages instantly it seems...
completely random.  I've checked the logs, no errors or anything that stands
out.  Some of the pages that slow down don't access replying via email, so
SMTP wouldn't be the issue.  I examined again my slow query logs for mysql
and yesterday got this:

# Time: 110523  2:30:10
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 6  Lock_time: 0  Rows_sent: 70390  Rows_examined: 70390
use rt3;
SELECT /*!40001 SQL_NO_CACHE */ * FROM `Attachments`;
# Time: 110523  2:30:17
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 4  Lock_time: 0  Rows_sent: 125353  Rows_examined: 125353
SELECT /*!40001 SQL_NO_CACHE */ * FROM `Transactions`;
# Time: 110523  2:30:20
# User at Host: rt_user[rt_user] @ localhost []
# Query_time: 3  Lock_time: 0  Rows_sent: 10343  Rows_examined: 10343
SELECT /*!40001 SQL_NO_CACHE */ * FROM `sessions`;


However, that's only 3 entries.. it happens much more often than that.  I'm
thinking I'll see the CPU peg out maybe 5 - 8  times in a 5 min span, for
about 10 - 15 seconds each time watching top.  My only thought is there's
some type of a miscommunication between apache and mysql, but I have no idea
what.  At this point, I'm open to any and all suggestions.  Please, if
anybody has any suggestions on where to look, I'd appreciate it.

On Thu, May 19, 2011 at 10:33 AM, Chris Hall <hiro24 at gmail.com> wrote:

> Well, resolved the below a bit by adding to RT_SiteConfig.pm:
>
> Set($WebSessionClass, "Apache::Session::File");
>
> However, CPU usage still peaks out on apache2 processes, although it
> appears to be not AS frequent.  Anybody have any other suggestions on areas
> to look into?  Some are saying the slowdown seems to occur most frequently
> when updating tickets.
>
>
> On Wed, May 18, 2011 at 8:36 PM, Chris Hall <hiro24 at gmail.com> wrote:
>
>> I actually saw something about that in a message to the mailing list, and
>> already turned it off as well, as a precaution.   After searching around
>> some and trying out some tests, it seems the delay happens after the GET
>> request to the apache server, and watching the logs, nothing appears in the
>> log until about 20 seconds after the request to say the user asked for it..
>> so there's about 20 - 30 seconds of dead time from the GET to when the log
>> shows a request was made.  On a forum recommendation, I enabled slow mysql
>> logging and noticed several entries in the log.  Here is a sample:
>>
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 3246  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-8a63b00ecb1829c65682fc75db1c05be', 3600);
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 3204  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-8a63b00ecb1829c65682fc75db1c05be', 3600);
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 2897  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-8a63b00ecb1829c65682fc75db1c05be', 3600);
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 2885  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-8a63b00ecb1829c65682fc75db1c05be', 3600);
>> # Time: 110518 19:51:37
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 1660  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-8a63b00ecb1829c65682fc75db1c05be', 3600);
>> # Time: 110518 19:56:44
>> # User at Host: rt_user[rt_user] @ localhost []
>> # Query_time: 14  Lock_time: 0  Rows_sent: 1  Rows_examined: 0
>> SELECT GET_LOCK('Apache-Session-29fd7421a2e8981d99740258bbb9aea3', 3600);
>>
>>
>> Dunno if they are of any help, but to me, it seems to indicate several
>> SELECT queries that are running long for... whatever reason.  Do these logs
>> make sense to anybody?
>>
>> On Wed, May 18, 2011 at 6:33 PM, Jonah Hirsch <jwh83 at nau.edu> wrote:
>>
>>> I was having this issue, same exact versions and problems with apache2. I
>>> turned off mod_deflate and that helped a bit, but I'm still getting some
>>> slowdowns, just not as much as before.
>>> -----------------------
>>>  Jonah Hirsch
>>>
>>>
>>>
>>> On Wed, May 18, 2011 at 11:31 AM, Chris Hall <hiro24 at gmail.com> wrote:
>>>
>>>> Not sure where to start here, but trying to diagnose why after an
>>>> upgrade from 3.8.8 to 4.0.0 things have slowed down tremendously.  Doing
>>>> even pedestrian tasks such as loading the home screen or opening the ticket
>>>> search will about 30% of the time decide it wants to max out the cpu with
>>>> the apache2 process for roughly 20 - 30 seconds.  Sometimes, loading things
>>>> happens almost instantaneously.  Other times, there's this weird delay.  Not
>>>> sure where to start looking, are there any known issues that I might need to
>>>> be aware of?
>>>
>>>
>>>
>>
>
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