Re: pg_upgrade bug found!

Jeff Davis wrote:
> On Thu, 2011-04-07 at 15:46 -0400, Bruce Momjian wrote:
> > OK, so the only other idea I have is to write some pretty complicated
> > query function that does a sequential scan of each toast table and pulls
> > the earliest xmin/xmax from the tables and use that to set the
> > relfrozenxid (pretty complicated because it has to deal with the freeze
> > horizon and wraparound).
> 
> That sounds like the correct way to fix the situation, although it's a
> little more work to install another function just for this one-time
> purpose. TransactionIdPrecedes() should already account for wraparound,
> so I don't think that it will be too complicated (make sure to read
> every tuple though, not just the ones currently visible).
> 
> Stepping back a second to make sure I understand the problem: the only
> problem is that relfrozenxid on the toast table after an upgrade is
> wrong. Correct?

One minimal solution might be to set the toast relfozenxid to match the
heap frozenxid?  Ideas?  It is not 100% accurate but it might help.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +