Re: pg_migrator to /contrib in a later 9.0 beta

Andrew Dunstan wrote:
> 
> 
> Bruce Momjian wrote:
> > For example, I assume there
> > will be some major version of Postgres where pg_migrator will not work
> > at all.
> >
> >   
> 
> We need to be thinking more now about such a contingency. Postgres use 
> in very large installations is now at such a level that requiring a 
> pg_dump/pg_restore is really not an option for many users. If 
> pg_migrator is not always going to work then we need to be addressing 
> that now, or else it is at best a stop-gap. ISTM some sort of page 
> layout versioning scheme might be at least part of what we'll need in 
> the medium term.

Yes, my bet is that when we do need to change the page format, we will
either use a conversion-on-read process or some external tool to do the
conversion.  pg_migrator does have code to do page conversions but it
has never been used.  If you are using pg_migrator in copy mode, we
might be able to do page conversion during the copy, but for link mode,
that is not possible.

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