On Sun, Jan 16, 2011 at 00:34, Josh Berkus <j...@agliodbs.com> wrote: > I think we can be more specific on that last sentence; is there even any > *theoretical* benefit to settings above 16MB, the size of a WAL segment? > Certainly there have been no test results to show any.
I don't know if it's applicable to real workloads in any way, but it did make a measurable difference in one of my tests. Back when benchmarking different wal_sync_methods, I found that when doing massive INSERTs from generate_series, the INSERT time kept improving even after increasing wal_buffers from 16MB to 32, 64 and 128MB; especially with wal_sync_method=open_datasync. The total INSERT+COMMIT time remained constant, however. More details here: http://archives.postgresql.org/pgsql-performance/2010-11/msg00094.php Regards, Marti -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
