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.
Hold, I overstated the fragility issue above. I now realize that the old system is not going to change and that I only need to worry about future changes, where are handled by the new -b flag, so maybe we can get away with only stopping autovacuum on the new server, but I would need someone to verify that, and this would be a change in the way 9.0 pg_upgrade operated because it did disable autovacuum on the old and new servers with 99.9% reliability. -- 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
