On Tue, Mar 6, 2018 at 3:12 PM, Natalie Wenz <nataliewenz@xxxxxxxxxxx> wrote: > What happens to the xid of rows/tables when you upgrade postgres via pg_upgrade? > > I upgraded a very large database from 9.6 to 10.1 via pg_upgrade recently, and ever since, the auto vacuum has been busy on a large legacy table that has experienced no changes since the upgrade. If the whole table had been frozen prior to the upgrade, would you expect it to stay frozen? Yes, you're right to expect it to stay frozen. I wonder if this is due to a (thankfully relatively benign) bug that was fixed very recently [1]. Are the relations that autovacuum is processing materialized views? [1] https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=38b41f182a66b67e36e2adf53d078599b1b65483 -- Peter Geoghegan
