On Sun, May 12, 2013 at 8:50 AM, Andres Freund <andres@xxxxxxxxxxxxxxx> wrote: > [ a response that I entirely agree with ] +1 to all that. It's maybe worth noting that it's probably fairly uncommon for vacuum to read a page and not dirty it, because if the page is all-visible, we won't read it. And if it's not all-visible, and there's nothing else interesting to do with it, we'll probably make it all-visible, which will dirty it. It can happen, if for example we vacuum a page with no dead tuples while the inserting transaction is still running, or committed but not yet all-visible. Of course, in those cases we won't be able to freeze, either. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
