> I think that most of the arguments in this thread drastically
> overestimate the precision and the effect of effective_cache_size. The
> planner logic behind it basically only uses it to calculate things
> within a single index scan. That alone shows that any precise
> calculation cannot be very meaningful.
> It also does *NOT* directly influence how the kernel caches disk
> io. It's there to guess how likely it is something is still cached when
> accessing things repeatedly.
Agreed. I think we should take the patch as-is, and spend the rest of
the 9.4 dev cycle arguing about 3x vs. 4x.
;-)
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com