On Thu, Mar 11, 2021 at 07:50:16PM -0500, Stephen Frost wrote: > > So, my thought is to just upgrade the active side as normal, and once > > that's done and the master is back in use, stop the standby's > > postgres, call "pg_start_backup(...)" on the master, rsync the changed > > files from the running master's data dir to the standby's 10.x data > > directory, call "pg_stop_backup()", migrate the recovery.conf into a > > postgresql.auto.conf, touch the standby.signal file, and then start > > the new postgres 13 on the standby. That seems to work, but I want to > > be sure I'm not just having good luck due to the relatively low > > activity on my test systems. > > Exactly how are you doing this rsync..? A simplistic rsync would end up > just copying everything over and, as Bruce says later, if you're doing > that then you might as well just use pg_basebackup or a similar tool to > do it cleanly. In other words, I don't think that you're actually > getting the benefit that you think you are with this.. Note that the > file names are not kept the same after the pg_upgrade... > > Also- I don't think you realize how fast the rsync process to update the > standbys will be. Done correctly, it should be faster than the > pg_upgrade.. Note that you'll want to make sure you TRUNCATE and He/she wants to run the standby, I guess in read-only mode, while pg_upgrade is running, which is why I didn't even bother to mention that. I think if downtime is the critical for this person, he/she should be using logical replication for the upgrade. pg_upgrade really wants full control of the primary/standbys during its operation, and if you can't do that, pg_upgrade is not the right tool to use. > unlogged tables before the pg_upgrade, et al, otherwise you'll end up > rsync'ing those over. Also make sure you haven't got any stray or > forgotten temp files or other things. Again, done properly, the rsync > to upgrade the standbys should only be copying the catalog tables > themselves and it should be quite fast. Yes, good points. -- Bruce Momjian <bruce@xxxxxxxxxx> https://momjian.us EDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
