wal_sync_methods for AIX

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.

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?

thanks

--
Dan Langille -- http://www.langille.org/
dan@langille.org