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
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