On Fri, Jul 24, 2009 at 1:13 AM, Marc Cousin<cousinmarc@xxxxxxxxx> wrote: >> It really has very little impact. It only affects index scans, and >> even then only if effective_cache_size is less than the size of the >> table. >> >> Essentially, when this kicks in, it models the effect that if you are >> index scanning a table much larger than the size of your cache, you >> might have to reread some blocks that you previously read in during >> *that same index scan*. > > Ok, thanks for clearing that up for me. Still, I think the doc could be > improved on this point (sorry to be a bit obsessed with that, but I'm one of > the french translators, so I like the doc to be perfect :) ) Yes, I agree. I was confused for quite a long time, too, until I read the code. I think many people think this value is much more important than it really is. (That having been said, I have no current plans to write such a doc patch myself.) ...Robert -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
