[rt-users] ShowCustomFields extremely slow.

Michelle Sullivan michelle at sorbs.net
Mon Jan 27 20:16:01 EST 2014


Michelle Sullivan wrote:
> Michelle Sullivan wrote:
>   
>> Alex Vandiver wrote:
>>   
>>
>>     
>>>>   
>>>>       
>>>>         
>>> The fact that even cookie setup takes a quarter of a second is
>>> problematic, and suggests that your database badly needs tuning.
>>>   
>>>     
>>>       
>> I doubt it, it's probably because it's busy.
>>   
>>     
>
> Oh I should also point out in lulls between incoming spam runs when the
> DBs drop to just 1-2 qps (which happens for 15 minute periods every
> couple of hours, the query speed for the RT4 DB doesn't change
> noticeably - the trace was taken during one of the quiet periods)
>
>   
Also monitoring the process list whilst it's sitting there in
ShowCustomFields I see no queries...  On the occasion I do pick up a
query (eg after a restart of the DB, or after a vacuum) it's very
obviously being slowed by index loading (can be 10 seconds or so) then
the query time drops to a few ms.. however this is not the cause (would
be fairly easy to identify.)


I suspected it might be a lock in the DB(s) but checking the locks I see
nothing waiting.

I suspected it might be a run-away perl process... but the apache server
is idle..

I suspected (in desperation) maybe I had configured the resolver badly..
not that either...

The only thing I can think of is something to do with the custom fields
and it's returning 1000's of rows (very quick for the query, but slow to
transfer due to network latency (~20ms round trip) - Primary DB
(hardcoded on the test servers) is in Santa Clara, webserver is in
Seattle)...

rt4=# select count(1) from objectcustomfieldvalues;
 count 
--------
 100689
(1 row)

rt4=# select count(1) from objectcustomfields;    
 count
-------
    36
(1 row)

Everytime the problem is in ShowCustomFields taking >60s (and averaging
400s)


Regards,

-- 
Michelle Sullivan
http://www.mhix.org/



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