On Thu, 13 Mar 2008, Craig James wrote:
wal_sync_method = open_sync
There was a bug report I haven't had a chance to investigate yet that suggested some recent Linux versions have issues when using open_sync. I'd suggest popping that back to the default for now unless you have time to really do a long certification process that your system runs reliably with it turned on.
I suspect most of the improvement you saw from Joshua's recommendations was from raising checkpoint_segments.
$ pgbench -c 10 -t 10000 -v test -U test scaling factor: 1 number of clients: 10
A scaling factor of 1 means you are operating on a positively trivial 16MB database. It also means there's exactly one entry in a table that every client updates on every transactions. You have 10 clients, and they're all fighting over access to it.
If you actually want something that approaches useful numbers here, you need to at run 'pgbench -i -s 10' to get a scaling factor of 10 and a 160MB database. Interesting results on this class of hardware are when you set scaling to 100 or more (100=1.6GB database). See http://www.westnet.com/~gsmith/content/postgresql/pgbench-scaling.htm for some examples of how that works, from a less powerful system than yours.
-- * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
