Cédric Villemain wrote:
> AFAIK effective_cache_size is estimation of OS Page Cache + Estimated
> Cache in shared_buffers.
>
Yes, the total value you set is used as is, and should include both
pieces of memory. The planner doesn't add the shared_buffers value to
the total first for you, as some people might guess it would.
The only thing effective_cache_size is used for is estimating how
expensive an index is likely to be to use, to make decisions like when
to do an index-based scan instead of just scanning the table itself.
--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.com
