On Wed, Feb 29, 2012 at 5:52 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Wed, Feb 29, 2012 at 4:34 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> Easier for who? I don't care for the idea of code that has to cope with >>> two page formats, or before long N page formats, because if we don't >>> have some mechanism like this then we will never be able to decide that >>> an old data format is safely dead. > >> Huh? You can drop support for a new page format any time you like. >> You just decree that version X+1 no longer supports it, and you can't >> pg_upgrade to it until all traces of the old page format are gone. > > And how would a DBA know that?
We'd add a column to pg_class that tracks which page version is in use for each relation. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers