I have moved the data directory (xlog, base, global, and everything) to an ext4 file system. The result hasn't changed unfortuately. With the same load test the average response time: 80ms; from 40ms to 120 ms everything occurs. This ext4 has default settings in fstab. Have you got any other idea what is going on here?
Thanks, Otto 2011/12/8 Marti Raudsepp <ma...@juffo.org> > On Thu, Dec 8, 2011 at 06:37, Aidan Van Dyk <ai...@highrise.ca> wrote: > > Let me guess, debian squeeze, with data and xlog on both on a single > > ext3 filesystem, and the fsync done by your commit (xlog) is flushing > > all the dirty data of the entire filesystem (including PG data writes) > > out before it can return... > > This is fixed with the data=writeback mount option, right? > (If it's the root file system, you need to add > rootfsflags=data=writeback to your kernel boot flags) > > While this setting is safe and recommended for PostgreSQL and other > transactional databases, it can cause garbage to appear in recently > written files after a crash/power loss -- for applications that don't > correctly fsync data to disk. > > Regards, > Marti >
