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.
There are other statistics views, see
http://www.postgresql.org/docs/8.4/static/monitoring-stats.html#MONITORING-STATS-VIEWS
> Another question is, what is the best memory configuration to
> keep more data in cache?
That's easy - the greater shared_buffers is, the more cache you have.
Another option is to choose shared_buffers not too large and let
the filesystem cache buffer the database for you.
Yours,
Laurenz Albe