Re: pg_upgrade bug found!

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?

Regards,
	Jeff Davis