On Tue, May 28, 2024 at 05:24:56PM -0400, Ron Johnson wrote: > On Tue, May 28, 2024 at 3:11 PM Johannes Truschnigg < > >[...] > > Yes, replication slots can interrupt your primary. > > > > Please define "interrupt". Using a replication slot, I thought files would > just accumulate in pg_wal while the replica is down (or the network is > slow, or the replica can't keep up with the primary). > > Disaster, of course, when that disk fills up, but that's always been the > case. And that is exactly the scenario I meant when I said "interrupt". If you use replication slots, your monitoring/alerting isn't set up correctly, and you're accumulating a lot of WAL, chances are ENOSPC on the primary is around the corner for you. That's why I generally prefer a WAL archive on a separate file system for replicas to source segments from, because filling that up won't break the primary (unless the archive_command misbehaves). That also needs proper monitoring/alerting, of course (and a contingency plan for what to do when/if the archive runs over) - but everyone whose workload is important enough for a replication setup to make sense is required to have that in my book. -- with best regards: - Johannes Truschnigg ( johannes@xxxxxxxxxxxxxxx ) www: https://johannes.truschnigg.info/
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