On Fri, 2009-10-30 at 07:15 -0400, Steve Clark wrote: > On 10/29/2009 04:42 PM, Scott Marlowe wrote: > > On Thu, Oct 29, 2009 at 12:46 PM, Vick Khera<vivek@xxxxxxxxx> wrote: > >> On my primary DB I'm observing random slowness which just doesn't make > >> sense to me. The I/O system can easily do 40MB/sec writes, but I'm > >> only seeing a sustained 5MB/sec, even as the application is stalling > >> waiting on the DB. > > > > Just one point on top of everything else you'll hear. 40 MB/sec > > sequential throughput does not equal 40MB/sec random PLUS checkpoint > > throughput. Random access is gonna lower that 40MB/sec way down real > > fast. > > > > First step to speed things up is putting pg_xlog on its own disk(s). > Hi Scott, > > How exactly do you do this? By creating a link to the new location or > is there a config option somewhere that says where the pg_xlog resides? There is an option to do this during initdb. If you want to do it after the DB is created, move the contents of pg_xlog/ (when the DB is shut down) and make a symlink to the new directory. -- Brad Nicholson 416-673-4106 Database Administrator, Afilias Canada Corp. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
