Re: Postmaster only takes 4-5% CPU

Hi:

I'm sorry to get back with this, but I claimed victory too soon.
Postmaster is back (intermitently) taking just a small % of cpu while
system is almost 100% idle, as you can see in "top" below.

Any ideas of how can I fix this? Programs running queries are going too
slooooow.

Thanks!

11:21am up 7 days, 21:00, 6 users, load average: 1,10, 1,04, 0,86
106 processes: 102 sleeping, 4 running, 0 zombie, 0 stopped
CPU states: 0,5% user, 1,7% system, 0,0% nice, 97,6% idle
Mem: 1031012K av, 1019052K used, 11960K free, 0K shrd, 11340K buff
Swap: 2040244K av, 153828K used, 1886416K free 958512K cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
23057 postgres 15 0 3316 3136 2292 R 1,1 0,3 0:17 postmaster
23073 postgres 15 0 1096 1096 840 R 0,1 0,1 0:00 top
1 root 15 0 468 428 416 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_C
5 root 15 0 0 0 0 SW 0,0 0,0 1:18 kswapd
6 root 15 0 0 0 0 SW 0,0 0,0 0:07 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 0:29 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

scott.marlowe wrote:
> Under some circumstances, on my (somewhat) older 7.2 box running the 2.4.9
> kernel, the kswapd and bdflush daemons will start working overtime when
> there are accesses by windows users via samba to look through large
> directories.
>
> This makes the box QUITE slow and pokey, and all the tasks that are
> running besides kswapd / bdflush are in D state mostly, while the swap
> daemon eats 0 to 100% CPU depending on some change in state in samba I've
> not bothered tracking down.
>
> I understand a newer kernel might be a good thing for me, so eventually
> I'll do that. For now I just put the Windows Samba people on another box.
> They both go through the the same NAS, and it keeps the load off the main
> server.
>
> So, look for other processes that might be doing something like scanning a
> directory of 40,000 files or some such.
>
> On Thu, 29 May 2003, Ruben wrote:
>
>
>>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
>>>
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 2: you can get off all lists at once with the unregister command
>> (send "unregister YourEmailAddressHere" to majordomo(at)postgresql(dot)org)
>>
>
>