Re: High CPU Load

On Thu, 2006-09-14 at 09:00, Jérôme BENOIS wrote:
> Hi Guillaume,
>
> Le jeudi 14 septembre 2006 à 15:46 +0200, Guillaume Smet a écrit :
> > On 9/14/06, Jérôme BENOIS <benois(at)argia-engineering(dot)fr> wrote:
> > > I migrated Postgres server from 7.4.6 to 8.1.4, But my server is
> > > completely full, by moment load average > 40
> > > All queries analyzed by EXPLAIN, all indexes are used .. IO is good ...
> >
> > What is the bottleneck? Are you CPU bound? Do you have iowait? Do you
> > swap? Any weird things in vmstat output?
> the load average goes up and goes down between 1 and 70, it's strange.
> IO wait and swap are good. I have just very high CPU load. And it's user
> land time.
>
> top output :
>
> top - 15:57:57 up 118 days, 9:04, 4 users, load average: 8.16, 9.16,
> 15.51
> Tasks: 439 total, 7 running, 432 sleeping, 0 stopped, 0 zombie
> Cpu(s): 87.3% us, 6.8% sy, 0.0% ni, 4.8% id, 0.1% wa, 0.2% hi,
> 0.8% si
> Mem: 2076404k total, 2067812k used, 8592k free, 13304k buffers
> Swap: 1954312k total, 236k used, 1954076k free, 1190296k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 15667 postgres 25 0 536m 222m 532m R 98.8 11.0 1:39.29 postmaster
> 19533 postgres 25 0 535m 169m 532m R 92.9 8.3 0:38.68 postmaster
> 16278 postgres 25 0 537m 285m 532m R 86.3 14.1 1:37.56 postmaster
> 18695 postgres 16 0 535m 171m 532m S 16.1 8.5 0:14.46 postmaster
> 18092 postgres 16 0 544m 195m 532m R 11.5 9.7 0:31.87 postmaster
> 16896 postgres 15 0 534m 215m 532m S 6.3 10.6 0:27.13 postmaster

Somewhere, the query planner is likely making a really bad decision.

Have you analyzed your dbs?