Re: High CPU load on Postgres Server during Peak times!!!!

Andy Colson wrote:
> Shiva Raman wrote:
>> Dear all
>>
>> I am having a problem of high cpu loads in my postgres server during
>> peak time. Following are the
>> details of my setup (details as per the postgres wiki) .
>>
>>
>> *Following is the output of TOP command during offpeak time.*
>>
>>
>> top - 18:36:56 up 77 days, 20:33, 1 user, load average: 12.99, 9.22,
>> 10.37
>> Tasks: 142 total, 12 running, 130 sleeping, 0 stopped, 0 zombie
>> Cpu(s): 46.1%us, 1.9%sy, 0.0%ni, 6.1%id, 3.0%wa, 0.0%hi, 0.1%si,
>> 42.9%st
>> Mem: 16133676k total, 13657396k used, 2476280k free, 450908k buffers
>> Swap: 14466492k total, 124k used, 14466368k free, 11590056k cached
>>
>
>
> First off, nice report.
>
> I see you are on a pretty old version of pg. Are you vacuuming regularly?
>
> If you run a 'ps ax|grep post' do you see anything that says 'idle in
> transaction'? (I hope that old of version will show it. my processes
> show up as postgres not postmaster)
>
> The top looks like you are cpu bound. Have you tried enabling logging
> slow queries? (again, I hope your version supports that) It could be
> you have a query or two that are not using indexes, and slowing
> everything down.
>
> Also on the top, it has this: 42.9%st. Are you in a vm? or running
> vm's on the box?
>
> Its weird, you have 6.1% idle and 3.0% waiting for disk and yet you have
> a load of 13. Load usually means somebody is waiting for something. But
> you have a little cpu idle time... and you have very low disk waits...
> you are using very little swap. hum... odd...
>
> -Andy
>

Looks like I missed an important point. You said this was top during
off peak time. So ignore my high load ramblings.

But... if this is off peak, and you only have 6% idle cpu... I'd say
your cpu bound. (I'm still not sure what the 42.9%st is, so maybe I'm
off base with the 6% idle too)

-Andy