On Feb 15, 2008, at 3:55 PM, Dan Langille wrote:
We're using PostgreSQL 8.1.11 on AIX 5.3 and we've been doing some
playing around
with various settings. So far, we've (I say we, but it's another
guy doing the work) found
that open_datasync seems better than fsync. By how much, we have
not yet determined,
but initial observations are promising.
Here's a good explanation (by the Greg Smith) on the different sync
methods. It basically says that if you have open_datasync available,
it'll probably beat everything else.
Our tests have been on a p550 connected to DS6800 array using pgbench.
One nasty behaviour we have seen is long running commits. Initial
thoughts connected
them with checkpoints, but the long running commits do not
correlate with checkpoints being
written. Have you seen this behaviour?
FYI, 8.3.0 is not an option for us in the short term.
What have you been using on AIX and why?
I really don't know anything about AIX, but are you sure that these
long running commits are directly correlated with using open_datasync?
Erik Jones
DBA | Emma®
erik@xxxxxxxxxx
800.595.4401 or 615.292.5888
615.292.0777 (fax)
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