On Fri, Aug 28, 2009 at 8:19 PM, Jeff Janes<jeff.janes@xxxxxxxxx> wrote: >> ---------- Forwarded message ---------- >> From: Joseph S <jks@xxxxxxxxxxxxxxx> >> To: Greg Smith <gsmith@xxxxxxxxxxxxx>, pgsql-performance@xxxxxxxxxxxxxx >> Date: Fri, 28 Aug 2009 10:25:10 -0400 >> Subject: Re: What exactly is postgres doing during INSERT/UPDATE ? >> Greg Smith wrote: >> >>> The main two things you can do to improve this on the database side: >>> >>> -Increase checkpoint_segments, which reduces how often updated data has >>> to be flushed to disk >> >> It fsync is turned off, does this matter so much? > > It still matters. The kernel is only willing to have so much dirty data > sitting in the disk cache. Once it reaches that limit, user processes doing > writes start blocking while the kernel flushes stuff on their behalf. it doesn't matter nearly as much though. if you are outrunning the o/s write cache with fsync off, then it's time to start looking at new hardware. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
