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@postgresql.org)
>>
>
>