Re: A Modest Upgrade Proposal

On Thu, Jul 28, 2016 at 10:22 AM, Craig Ringer <craig(at)2ndquadrant(dot)com> wrote:
> It might, actually. One approach for online upgrade is to:
>
> * pg_basebackup the master
> * start the replica and let it catch up
> * create a logical replication slot on the master
> * replace the replication.conf on the basebackup so it stops recovery at the
> lsn of the replication slot's confirmed_flush_lsn
> * stop the replica and pg_upgrade it
> * have the upgraded replica, now a master, replay from the old master over
> logical replication
> * once caught up, switch over
>
> This means a full dump and reload with a full rebuild of all indexes, etc,
> isn't needed. All shared catalog stuff is copied (until we switch to logical
> rep for the final catch-up).

This is a per-database logic to perform an upgrade of a single
database, right? If a cluster has multiple databases you need one
logical slot per database to complete an upgrade, which is where
sync_synchronous_names which is able to take now multiple entries
helps as well to ensure that the former master is in sync with the all
the logical slots in place.
--
Michael