On Tue, 2004-12-14 at 09:23 -0500, Tom Lane wrote:
> At this point in the release cycle I'm not sure we should be making
> any significant changes for anything less than a crashing bug.
Yes, that's true, and I am definitely hesitant to make changes during
RC. That said, "adjust bgwriter defaults" has been on the "open items"
list for quite some time -- in some sense #2 is just a variant on that
idea.
> I'd want to see some pretty impressive benchmark results before we
> consider making a change now.
http://archives.postgresql.org/pgsql-hackers/2004-12/msg00426.php
is with a patch from Simon that implements #3. While that's not exactly
the same as #2, it does seem to suggest that the performance difference
is rather noticeable. If the problem does indeed exacerbate BufMgrLock
contention, it might be more noticeable still on an SMP machine.
I'm going to try and get some more benchmark data; if anyone else wants
to try the patch and contribute results they are welcome to.
-Neil