Re: Patch for pg_upgrade to turn off autovacuum

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Bruce Momjian <bruce@momjian.us>

Cc: Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Alvaro Herrera <alvherre@commandprompt.com>, Jeff Davis <pgsql@j-davis.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2011-04-22T21:22:54Z

Lists: pgsql-hackers

Bruce Momjian <bruce@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.

			regards, tom lane