On Wed, Apr 13, 2011 at 5:26 PM, Tomas Vondra <tv@xxxxxxxx> wrote: > Workload A: Touches just a very small portion of the database, to the > 'active' part actually fits into the memory. In this case the cache hit > ratio can easily be close to 99%. > > Workload B: Touches large portion of the database, so it hits the drive > very often. In this case the cache hit ratio is usually around RAM/(size > of the database). I've had this kind of split-brain operation in the past, where 99% of all accesses would be cached, and the 1% that weren't needed their own tuning. Luckily you can tune by user (alter user set random_page_cost etc) so I was able to do that. One of the best features of pgsql imnsho. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
