From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Doug Fields <dfields-pg-general(at)pexicom(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org, Glenn Stone <gstone(at)pogolinux(dot)com> |
Subject: | Re: WAL recycling, ext3, Linux 2.4.18 |
Date: | 2002-07-08 15:57:31 |
Message-ID: | 17774.1026143851@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Doug Fields <dfields-pg-general(at)pexicom(dot)com> writes:
> I'm still trying to track down my very odd periodic pauses/hangs in
> PostgreSQL 7.2.1.
> I've localized it to what seems to be the "recycled transaction log file"
> lines in the log file. Whenever this happens, a whole bunch of queries
> which were "on hold" (just sitting there, as can be seen in
> pg_stat_activity, when they usually execute in fractions of a second) come
> back to life and finish very quickly.
Hm. That would be from the tail end of a checkpoint operation. If you
do a CHECKPOINT command manually, do you get a similar hangup?
What are the stuck queries doing exactly? Can you attach to a few of the
stuck backends with gdb and get stack traces?
> 1) Is there any known bad interactions with ext3fs and PostgreSQL?
Dunno. The CHECKPOINT would probably create a significant number of
disk write requests, followed by a sync() request. If that could
monopolize an ext3 filesystem for a long time, perhaps that would
explain your problem. But I haven't heard similar complaints before.
What do you have shared_buffers set to?
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Doug Fields | 2002-07-08 16:04:31 | Re: WAL recycling, ext3, Linux 2.4.18 |
Previous Message | Thomas Lockhart | 2002-07-08 15:51:34 | Re: fractional timezones |