Re: Resurrecting pg_upgrade

> Per prior discussion, we will enforce some sort of limit on how often
> the representation of user tables/indexes can be changed.  The idea will
> be to "batch" such changes so that you only have to do a dump/reload
> every N major releases instead of every one.  In other words, pg_upgrade
> will work for most version upgrades but we reserve the right to
> occasionally make releases where it doesn't work.
> 
> How large N will be in practice remains to be seen, of course, but I'd
> expect something on the order of 4 or 5.
> 
> In theory pg_upgrade could be made to apply changes in user data
> representation, but I'm unconvinced that such a process would be a big
> improvement over dump/reload.

Will we now have to be careful to NEVER re-use OIDs in the system catalogs.

Chris