On 2014-11-06 23:40:18 +0000, Greg Stark wrote: > On Thu, Nov 6, 2014 at 9:30 PM, Andres Freund <and...@2ndquadrant.com> wrote: > > I think the retry logical is a largely pointless complication of already > > complex enough code. You're fixing a problem for which there is > > absolutely no evidence of its existance. Yes, this happens > > occasionally. But it's going to be so absolutely minor in comparison to > > just about every other source of bloat. > > I agree bloat isn't really a threat, but what about the relfrozenxid? > If we skip even one page we don't get to advance it and retrying could > eliminate those skipped pages and allow us to avoid a vacuum freeze > which can be really painful. Of course that only works if you can be > sure you haven't overflowed and forgotten any skipped pages and if you > don't find the page still pinned every time until you eventually give > up on it.
I don't buy this argument. Either you're constantly vacuuming the whole relation anyway - in which case we'll acquire the cleanup lock unconditionally - or we're doing partial vacuums via the visibility map anyway. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
