On 1/15/11 4:30 PM, Bruce Momjian wrote: > Josh Berkus wrote: >> Last I remember, we were going to add this as an option. But I don't >> see a patch in the queue. Am I missing it? Was I supposed to write it? > > I don't know, but let me add that I am confused how this would look to > users. In many cases, kernels don't even support O_DIRECT, so what > would we do to specify this? What about just auto-disabling O_DIRECT if > the filesystem does not support it; maybe issue a log message about it.
Yes, you *are* confused. The problem isn't auto-disabling, we already do that. The problem is *auto-enabling*; ages ago we made the assumption that if o_sync was supported, so was o_direct. We've now found out that's not true on all platforms. Also, test results show that even when supported, o_direct isn't necessarily a win. Hence, the additional fsync_method options. -- -- Josh Berkus PostgreSQL Experts Inc. http://www.pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers