Le jeudi 22 octobre 2009 00:06:10, Scott Marlowe a écrit : > 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. > pgfincore let you know if block are in OS kernel cache or not. -- Cédric Villemain Administrateur de Base de Données Cel: +33 (0)6 74 15 56 53 http://dalibo.com - http://dalibo.org
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