On May 24, 2010, at 4:25 AM, Konrad Garus wrote: > Do shared_buffers duplicate contents of OS page cache? If so, how do I > know if 25% RAM is the right value for me? Actually it would not seem > to be true - the less redundancy the better.
You can look into the pg_buffercache contrib module. > Another question - is there a tool or built-in statistic that tells > when/how often/how much a table is read from disk? I mean physical > read, not poll from OS cache to shared_buffers. Well, the pg_stat_* tables tell you how much logical IO is going on, but postgres has no way of knowing how effective the OS or disk controller caches are. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
