Re: URGENT: Out of disk space pg_xlog - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: URGENT: Out of disk space pg_xlog
Date
Msg-id 200612231813.kBNIDpK24705@momjian.us
Whole thread Raw
In response to Re: URGENT: Out of disk space pg_xlog  ("Jeremy Haile" <jhaile@fastmail.fm>)
Responses Re: URGENT: Out of disk space pg_xlog
List pgsql-performance
Jeremy Haile wrote:
> > > Once you free some space on the data partition and restart, you should
> > > be good to go --- there will be no loss of committed transactions, since
> > > all the operations are in pg_xlog.  Might take a little while to replay
> > > all that log though :-(
> >
> > Amazing that all works.  What I did not see is confirmation from the
> > user that the data directory filled up _before_ pg_xlog filled up.
>
> After I freed up space on the pg_xlog partition and restarted, it took
> some time to replay all of the log (15-20 minutes) and everything
> recovered with no data corruption!  However, the theory about the data
> partition filling up first didn't happen in my case.  The data partition
> was (and still is) less than 50% utilized.  My pg_xlog files typically
> run around 400MB, but with the long running update filled up the entire
> 10GB partition.  (which is now a 70 GB partition)
>
> So, I'm still not sure what caused the problem.  When I get back to work
> (or maybe sooner), I'll take a look in the PG logs and post anything
> that looks suspicious here.  Thanks for all of your comments and
> suggestions.  Even though I haven't figured out the root of the problem
> yet, they've been very informative.

The bottom line is that we know of now cases where a long-running
transaction would delay recycling of the WAL files, so there is
certainly something not understood here.

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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