On Fri, 2011-04-22 at 17:34 -0400, Bruce Momjian wrote: > Tom Lane wrote: > > Bruce Momjian <br...@momjian.us> writes: > > > I thought some more about this and I don't want autovacuum to run on the > > > old server. This is because pg_dumpall --binary-upgrade --schema-only > > > grabs the datfrozenxid for all the databases at the start, then connects > > > to each database to gets the relfrozenxids. I don't want to risk any > > > advancement of either of those during the pg_dumpall run. > > > > Why? It doesn't really matter --- if you grab a value that is older > > than the latest, it's still valid. As Robert said, you're > > over-engineering this, and thereby introducing potential failure modes, > > for no gain. > > Uh, I am kind of paranoid about pg_upgrade because it is trying to do > something Postgres was never designed to do. I am a little worried that > we would be assuming that pg_dumpall always does the datfrozenxid first > and if we ever did it last we would have relfrozenxids before the > datfrozenxid. I am worried if we don't prevent autovacuum on the old > server that pg_upgrade will be more fragile to changes in other parts of > the system.
If we back-patch the "-b" to 8.3, then we can always use it on both the old and new systems. Upgrading to the latest patch-level on both old and new should be a prerequisite for pg_upgrade anyway. That would turn the catalog check from a special case (use "-b" sometimes, other times don't; which could cause fragility and bugs), into just another sanity check with an easy workaround ("your postgres doesn't support '-b', upgrade to the latest patch-level before upgrading"). One of the things I like about the design of pg_upgrade is that it doesn't seem to have a lot of special cases for different version combinations. What do you think? Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers