Le jeudi 22 octobre 2009 00:06:10, Scott Marlowe a écrit :
> On Wed, Oct 21, 2009 at 11:17 AM, Scott Carey <scott@richrelevance.com>
wrote:
> > On 10/15/09 11:27 PM, "Albe Laurenz" <laurenz.albe@wien.gv.at> 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.
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