>>> 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 How about adding a comment to the wiki performance page.... http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
