Re: pg_upgrade bug found!

Bruce Momjian wrote:
> Alvaro Herrera wrote:
> > 
> > Why is it important to have the original pg_clog files around?  Since
> > the transactions in question are below the freeze horizon, surely the
> > tuples that involve those transaction have all been visited by vacuum
> > and thus removed if they were leftover from aborted transactions or
> > deleted, no?  So you could just fill those files with the 0x55 pattern
> > (signalling "all transactions are committed") and the net result should
> > be the same.  No?
> > 
> > Forgive me if I'm missing something.  I haven't been following this
> > thread and I'm more than a little tired (but wanted to shoot this today
> > because I'm gonna be able to, until Monday).

To answer your other question, it is true we _probably_ could assume all
the rows were committed, except that again, vacuum might not have run
and the pages might not be full so single-page cleanup wasn't done
either.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +