Hi Scott, No, we didn't have a kernel update (it is still the stock Ubuntu 10.04 Server kernel ... 2.6.32.2). And in the meantime - this morning - I have discovered, that the rebooted server is again slowing down! It is not at the level of the not-rebooted-server (about 45 mins for the 3 Gig file)... it "only" needs 22 minutes, but it is already quite a bit away from the optimum of 3 minutes (or less). So, definitely, something is "deteriorating" in the system ...
And I also did dome readings with iostat -xd 5 ... And the target drive to which the output of the STDOUT is directed is below 1% utilization (mostly around 0.2 - 0.4%) with rare "peaks around 2-3% when it does a little bit more. And this is maybe one of the interesting observations. It seems to periodically "flush" a bit more out, just to fall asleep again (with minimum write activity). The drive, from which the reads come (the one, where PG-s data files are ... it is the 8-disk RAID 10), has a little bit more activity (utilization 6-8%) but this data is also - concurrently - in use by some apps reading from the DB (just, normal traffic on the DB). Andras Fabian -----Ursprüngliche Nachricht----- Von: Scott Marlowe [mailto:scott.marl...@gmail.com] Gesendet: Dienstag, 13. Juli 2010 09:45 An: Andras Fabian Cc: Tom Lane; pgsql-general@postgresql.org Betreff: Re: [GENERAL] PG_DUMP very slow because of STDOUT ?? On Tue, Jul 13, 2010 at 12:31 AM, Andras Fabian <fab...@atrada.net> wrote: > Hi Scott, > > Although I can't guarantee for 100% that there was no RAID rebuild at some > point, I am almost sure that it wasn't the case. Two machines - the ones > which were already in production - exhibited this problem. Both of them were > already up for some weeks. Now, the reboot rather "fixed" one of them instead > of making it worse (as your theory goes this way) the problem "disappeared" > (but I don't know for how long). Now, only one of the production machines has > the issue ... the one which wasn't rebooted. Strange, strange. Nevertheless > thank you for your idea ... this is exactly the way I try to approach the > problem, by making some theories and trying to prove or disapprove them :-) > Now I will try to further investigate along the tips from Craig and Greg. Was there maybe a kernel update that hadn't been applied by reboot? -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
