On Friday 05 November 2010 19:13:47 Tom Lane wrote: > Marti Raudsepp <ma...@juffo.org> writes: > > PostgreSQL's default settings change when built with Linux kernel > > headers 2.6.33 or newer. As discussed on the pgsql-performance list, > > this causes a significant performance regression: > > http://archives.postgresql.org/pgsql-performance/2010-10/msg00602.php > > > > NB! I am not proposing to change the default -- to the contrary -- > > this patch restores old behavior. > > I'm less than convinced this is the right approach ... > > If open_dsync is so bad for performance on Linux, maybe it's bad > everywhere? Should we be rethinking the default preference order? I fail to see how it could be beneficial on *any* non-buggy platform. Especially with small wal_buffers and larger commits (but also otherwise) it increases the amount of synchronous writes the os has to do tremendously.
* It removes about all benefits of XLogBackgroundFlush() * It removes any chances of reordering after writing. * It makes AdvanceXLInsertBuffer synchronous if it has to write outy Whats the theory about placing it so high in the preferences list? Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
