On Wed, Oct 21, 2009 at 11:17 AM, Scott Carey <scott@xxxxxxxxxxxxxxxxx> wrote: > > > > On 10/15/09 11:27 PM, "Albe Laurenz" <laurenz.albe@xxxxxxxxxx> wrote: > >> waldomiro wrote: >>> I need to know how much the postgres is going to disk to get >>> blocks and how much it is going to cache? witch is the >>> statistic table and what is the field that indicates blocks >>> reads from the disk and the memory cache? >> >> The view pg_statio_all_tables will show you the number of >> disk reads and buffer hits per table. > > My understanding is that it will not show that. Since postgres can't > distinguish between a read that comes from OS cache and one that goes to > disk, you're out of luck on knowing anything exact. > The above shows what comes from shared_buffers versus the OS, however. And > if reads are all buffered, they are not coming from disk. Only those that > come from the OS _may_ have come from disk. I think he meant pg's shared_buffers not the OS kernel cache. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
