On Thu, Feb 1, 2024 at 8:15 AM Euler Taveira <eu...@eulerto.com> wrote: > > On Mon, Jan 29, 2024, at 10:17 AM, Zhijie Hou (Fujitsu) wrote: > > Attach the V72-0001 which addressed above comments, other patches will be > rebased and posted after pushing first patch. Thanks Shveta for helping > address > the comments. > > > While working on another patch I noticed a new NOTICE message: > > NOTICE: changed the failover state of replication slot "foo" on publisher to > false > > I wasn't paying much attention to this thread then I start reading the 2 > patches that was recently committed. The message above surprises me because > pg_createsubscriber starts to emit this message. The reason is that it doesn't > create the replication slot during the CREATE SUBSCRIPTION. Instead, it > creates > the replication slot with failover = false and no such option is informed > during CREATE SUBSCRIPTION which means it uses the default value (failover = > false). I expect that I don't see any message because it is *not* changing the > behavior. I was wrong. It doesn't check the failover state on publisher, it > just executes walrcv_alter_slot() and emits a message. > > IMO if we are changing an outstanding property on node A from node B, node B > already knows (or might know) about that behavior change (because it is > sending > the command), however, node A doesn't (unless log_replication_commands = on -- > it is not the default). > > Do we really need this message as NOTICE? >
The reason for adding this NOTICE was to keep it similar to other Notice messages in these commands like create/drop slot. However, here the difference is we may not have altered the slot as the property is already the same as we want to set on the publisher. So, I am not sure whether we should follow the existing behavior or just get rid of it. And then do we remove similar NOTICE in AlterSubscription() as well? Normally, I think NOTICE intends to let users know if we did anything with slots while executing subscription commands. Does anyone else have an opinion on this point? A related point, I think we can avoid setting the 'failover' property in ReplicationSlotAlter() if it is not changed, the advantage is we will avoid saving slots. OTOH, this won't be a frequent operation so we can leave it as it is as well. -- With Regards, Amit Kapila.