On 28 October 2012 22:35, Jan Wieck <janwi...@yahoo.com> wrote: > The amount of WAL generated with full_page_writes=on is quite substantial. > For pgbench for example the ratio 20:1. Meaning with full_page_writes you > write 20x the amount you do without.
Sure, but as always, pgbench pessimises everything by having writes follow a uniform distribution, which is completely unrepresentative of the natural world. This will literally maximise the number of pristine full page images that need to be included. The actual frequency of checkpoints is a crucial factor here too, and you didn't mention anything about that. -- Peter Geoghegan http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training and Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
