On Mon, Feb 06, 2012 at 08:51:34AM +0100, Heikki Linnakangas wrote: > >I wonder if we should just dedicate 3 page header bits, call that the > >page version number, and set this new version number to 1, and assume > >all previous versions were zero, and have them look in the old page > >version location if the new version number is zero. I am basically > >thinking of how we can plan ahead to move the version number to a new > >location and have a defined way of finding the page version number using > >old and new schemes. > > Three bits seems short-sighted, but yeah, something like 6-8 bits > should be enough. On the whole, though. I think we should bite the > bullet and invent a way to extend the page header at upgrade.
I just emailed a possible layout that allows for future page version number expansion. I don't think there is any magic bullet that will allow for page header extension by pg_upgrade. If it is going to be done, it would have to happen in the backend while the system is running. Anything that requires pg_upgrade to do lots of reads or writes basically makes pg_upgrade useless. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
