On Fri, Apr 19, 2013 at 7:43 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: > On Fri, Apr 19, 2013 at 2:24 PM, Claudio Freire <klaussfre...@gmail.com> > wrote: >> >> >> Especially if there's some locality of occurrence, since analyze >> samples pages, not rows. > > > But it doesn't take all rows in each sampled page. It generally takes about > one row per page, specifically to avoid the problem you indicate. Maybe it > is possible to trick it into taking too many (for example, if most pages are > completely empty), but I haven't experienced that as being a problem.
Still, I remember a discussion where it was clear there was a bias towards sampling rows from the same page (or nearby), resulting in this particular problem. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
