On Thu, 2005-10-20 at 14:59 -0600, Robert Creager wrote: > On Thu, 20 Oct 2005 21:19:18 +0100 > Simon Riggs <[EMAIL PROTECTED]> wrote: > > > Try this to recreate the problem: > > http://archives.postgresql.org/pgsql-performance/2004-04/msg00280.php > > > > Yup, that does it. Three hits the level I see with my application ~100k. Two > hits about 50k, one does nothing (< 1k).
OK, good. IYKWIM Can you try a slight modification? Run 3 threads, but against 3 different otherwise identical test tables created using a name-only mod of the test script. e.g. test_data1, 2 and 3. This will hit a different pattern of lwlocks. If the CS is the same, then it will tell us that the issue is not data dependent. If the CS drops, it tells us that it is an activity performed on the precise data blocks rather than the shared data structures which is the issue. That would then account for why the effect appears to come and go in your own application, because the effect is actually dependant on the data distribution (which presumably varies in your tables). Just trying to more tightly bracket the failure-case behaviour.... Best Regards, Simon Riggs ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
