Re: Occasional giant spikes in CPU load

От: Tom Lane
Тема: Re: Occasional giant spikes in CPU load
Дата: ,
Msg-id: 8127.1270677548@sss.pgh.pa.us
(см: обсуждение, исходный текст)
Ответ на: Occasional giant spikes in CPU load  (Craig James)
Ответы: Re: Occasional giant spikes in CPU load  (Craig James)
Список: pgsql-performance

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indexes in partitioned tables - again  (Samuel Gendler, )
 Re: indexes in partitioned tables - again  (Robert Haas, )
  Occasional giant spikes in CPU load  (Craig James, )
   Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )
    Re: Occasional giant spikes in CPU load  (Craig James, )
     Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )
      Re: Occasional giant spikes in CPU load  (Craig James, )
       Re: Occasional giant spikes in CPU load  (David Rees, )
       Re: Occasional giant spikes in CPU load  (Tom Lane, )
       Re: Occasional giant spikes in CPU load  (Alan Hodgson, )
     Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )
   Re: Occasional giant spikes in CPU load  (Greg Smith, )
   Re: Occasional giant spikes in CPU load  (Tom Lane, )
    Re: Occasional giant spikes in CPU load  (Craig James, )
     Re: Occasional giant spikes in CPU load  (Steve Crawford, )
   Re: Occasional giant spikes in CPU load  (David Rees, )
    Re: Occasional giant spikes in CPU load  (Robert Haas, )
     Re: Occasional giant spikes in CPU load  (Craig James, )
      Re: Occasional giant spikes in CPU load  (David Rees, )
       Re: Occasional giant spikes in CPU load  (Robert Haas, )
        Re: Occasional giant spikes in CPU load  (Craig James, )
         Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )
         Re: Occasional giant spikes in CPU load  (Greg Smith, )
         Re: Occasional giant spikes in CPU load  (Tom Lane, )
          Re: Occasional giant spikes in CPU load  (Craig James, )
           Re: Occasional giant spikes in CPU load  (Tom Lane, )
            Re: Occasional giant spikes in CPU load  (Craig James, )
             Re: Occasional giant spikes in CPU load  ("Kevin Grittner", )
              Re: Occasional giant spikes in CPU load  (Craig James, )
             Re: Occasional giant spikes in CPU load  (Greg Smith, )
             Re: Occasional giant spikes in CPU load  (Tom Lane, )
              pgbench results on a new server  (Craig James, )
               Re: pgbench results on a new server  (Scott Marlowe, )
               Re: pgbench results on a new server  (Greg Smith, )
                Re: pgbench results on a new server  (Craig James, )
                 Re: pgbench results on a new server  (Merlin Moncure, )
                  Two fast searches turn slow when used with OR clause  (Craig James, )
                   Re: Two fast searches turn slow when used with OR clause  (Robert Haas, )
                 Re: pgbench results on a new server  (Greg Smith, )
           Re: Occasional giant spikes in CPU load  (Rajesh Kumar Mallah, )
         Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )
      Re: Occasional giant spikes in CPU load  (Bruce Momjian, )
    Re: Occasional giant spikes in CPU load  (Greg Smith, )
   Re: Occasional giant spikes in CPU load  ("Joshua D. Drake", )

Craig James <> writes:
> Most of the time Postgres runs nicely, but two or three times a day we get a huge spike in the CPU load that lasts
justa short time -- it jumps to 10-20 CPU loads.  Today it hit 100 CPU loads.  Sometimes days go by with no spike
events. During these spikes, the system is completely unresponsive (you can't even login via ssh). 
> I managed to capture one such event using top(1) with the "batch" option as a background process.  See output below -
itshows 19 active postgress processes, but I think it missed the bulk of the spike. 

> Any ideas where I can look to find what's triggering this?

> Postgres 8.3.0
           ^^^^^

If it's really 8.3.0, try updating to 8.3.something-recent.  We've fixed
a whole lot of bugs since then.

I have a suspicion that this might be an sinval overrun scenario, in
which case you'd need to update to 8.4 to get a real fix.  But updating
in the 8.3 branch would be cheap and easy.

If it is sinval overrun, it would presumably be triggered by a whole lot
of catalog changes being made at approximately the same time.  Can you
correlate the spikes with anything like that?

            regards, tom lane


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