Re: Idea for getting rid of VACUUM FREEZE on cold pages

Alvaro Herrera wrote:
> Excerpts from Bruce Momjian's message of vie jun 04 15:39:07 -0400 2010:
> > Tom Lane wrote:
> > > Bruce Momjian <bruce@momjian.us> writes:
> > > > With in-place VACUUM FULL gone in 9.0, will there be as much need for
> > > > xmin/xmax forensics?
> > > 
> > > You know perfectly well that no one could answer that question.
> > > (Or at least not answer it on the basis of facts available today.)
> > 
> > Well, guess then.  In the past, how many forensic cases were needed for
> > in-place VACUUM FULL bugs, vs. other cases?
> 
> I don't understand the question.  I know I have debugged a bunch of
> cases of data corruption, and having xmin/xmax around has been truly
> useful.  VACUUM FULL has never been involved (that I know of -- most of
> our customers tend not to run it AFAIK), so why would I care about
> whether it's gone in 9.0?  Note that it's not always about PG bugs; but
> in the cases where xmin=FrozenXid for all/most involved tuples, the
> problems are more difficult to track down.
> 
> Yes, VACUUM FULL had bugs too -- I, for one, welcome our new
> not-in-place VACUUM FULL overlord.

OK, so we had lots of forensics the didn't involve VACUUM FULL.  That's
what I wanted to know.
--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + None of us is going to be here forever. +