On Thu, 26 Apr 2007, Zeugswetter Andreas ADI SD wrote:
I am not sure that shrinking per WAL record size (other than the full page images), e.g. by only logging changed bytes and not whole tuples, would have a huge impact on OLTP tx/sec, since the limiting factor is IO's per second and not Mb per second.
With the kind of caching controller that's necessary for any serious OLTP work with Postgres, number of I/Os per second isn't really an important number. Total volume of writes to the WAL volume can be though. It's difficult but not impossible to encounter a workload that becomes bottlenecked by WAL volume on a good OLTP server, particularly because that's often going to a single or RAID-1 disk. Whether those workloads also have the appropriate properties such that their WAL could be shrunk usefully in real-time is a good question.
-- * Greg Smith [EMAIL PROTECTED] http://www.gregsmith.com Baltimore, MD ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
