On Sun, Nov 21, 2010 at 11:07 PM, Andy Colson <a...@squeakycode.net> wrote: > After all this... there are too many numbers for me. I have no idea what > this means.
I think what it means that is that, for you, unlogged tables were almost as fast as shutting off all of synchronous_commit, full_page_writes, and fsync, and further setting bgwriter_lru_maxpages=0. Now, that seems a little strange, because you'd think if anything it would be faster. I'm not sure what accounts for the difference, although I wonder if checkpoints are part of it. With the current code, which doesn't exclude unlogged table pages from checkpoints, a checkpoint will still be faster with fsync=off than with unlogged tables. It seems like we're agreed that this is a problem to be fixed in phase two, though, either by fsyncing every unlogged table we can find at shutdown time, or else by providing two durability options, one that works as the current code does (but survives clean shutdowns) and another that excludes dirty pages from checkpoints (and does not survive clean shutdowns). -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
