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. > > There are other statistics views, see > http://www.postgresql.org/docs/8.4/static/monitoring-stats.html#MONITORING-STA > TS-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 > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
