Re: Postmaster only takes 4-5% CPU

Thanks for your answers Jan, Arjen, Shridar and Scott:

Postmaster is back taking lots of CPU when needed. I guess you were
right about Postgres waiting for some I/O activity. Anyway, I was not
able to see what process was responsible for this, since top showed
nothing remarkable.

This is a new top while running a VACUUM of the database:

8:51pm up 6:30, 3 users, load average: 0,45, 0,11, 0,04
93 processes: 89 sleeping, 4 running, 0 zombie, 0 stopped
CPU states: 0,1% user, 1,1% system, 0,0% nice, 98,6% idle
Mem: 1031012K av, 1019612K used, 11400K free, 0K shrd, 44896K buff
Swap: 2040244K av, 1716K used, 2038528K free 894008K cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
1673 postgres 15 0 5120 5120 3196 R 0,9 0,4 0:02 postmaster
1683 root 15 0 1044 1044 840 R 0,1 0,1 0:00 top
1 root 15 0 476 476 424 S 0,0 0,0 0:04 init
2 root 15 0 0 0 0 SW 0,0 0,0 0:00 keventd
3 root 15 0 0 0 0 SW 0,0 0,0 0:00 kapmd
4 root 34 19 0 0 0 SWN 0,0 0,0 0:00
ksoftirqd_CPU0
5 root 15 0 0 0 0 SW 0,0 0,0 0:00 kswapd
6 root 15 0 0 0 0 SW 0,0 0,0 0:00 bdflush
7 root 15 0 0 0 0 SW 0,0 0,0 0:00 kupdated
8 root 25 0 0 0 0 SW 0,0 0,0 0:00 mdrecoveryd
12 root 15 0 0 0 0 SW 0,0 0,0 0:00 kjournald
66 root 15 0 0 0 0 SW 0,0 0,0 0:00 khubd
266 root 15 0 0 0 0 SW 0,0 0,0 0:00 kjournald
267 root 15 0 0 0 0 SW 0,0 0,0 0:00 kjournald
268 root 15 0 0 0 0 SW 0,0 0,0 0:05 kjournald
269 root 15 0 0 0 0 SW 0,0 0,0 0:00 kjournald
547 root 15 0 0 0 0 SW 0,0 0,0 0:00 eth0

Cheers, Ruben.

Jan Poslusny wrote:
> Did not your postmaster wait for harddisk ?
>
> Ruben wrote:
>
>> Hi all:
>>
>> When I run a (big) query from pgsql, postmaster used to take almost
>> 100% of CPU. Now, with aparent no reason, Postmaster only takes 4-5%
>> CPU and the same query takes really longer to finish.
>>
>> I have tried renicing -20 postmaster but it still only takes a small
>> percentage of CPU, while 90% is idle.
>>
>> This is a "top" screen while running the query:
>>
>> 2:27pm up 5 min, 2 users, load average: 0,80, 0,26, 0,08
>> 74 processes: 72 sleeping, 2 running, 0 zombie, 0 stopped
>> CPU states: 3,1% user, 2,1% system, 0,0% nice, 94,6% idle
>> Mem: 1031012K av, 246040K used, 784972K free, 0K shrd,
>> 11496K buff
>> Swap: 2040244K av, 0K used, 2040244K free
>> 196916K cached
>>
>> PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
>> 1165 postgres 0 -20 3476 3476 2912 D < 4,5 0,3 0:02 postmaster
>> 268 root 15 0 0 0 0 SW 0,1 0,0 0:00 kjournald
>>
>> Any idea of how can I get postmaster to eat as much CPU as possible?
>>
>> Thanks a lot! Ruben.
>>
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 4: Don't 'kill -9' the postmaster