On Wed, Feb 15, 2023 at 11:48 PM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2023-02-15 18:02:11 +0530, Ashutosh Sharma wrote: > > Thanks Andres. I have one more query (both for you and Bertrand). I > > don't know if this has already been answered somewhere in this mail > > thread, if yes, please let me know the mail that answers this query. > > > > Will there be a problem if we mandate the use of physical replication > > slots and hot_standby_feedback to support minimum LD on standby. I > > know people can do a physical replication setup without a replication > > slot or even with hot_standby_feedback turned off, but are we going to > > have any issue if we ask them to use a physical replication slot and > > turn on hot_standby_feedback for LD on standby. This will reduce the > > code changes required to do conflict handling for logical slots on > > standby which is being done by v50-0001 and v50-0002* patches > > currently. > > I don't think it would. E.g. while restoring from archives we can't rely on > knowing that the slot still exists on the primary. > > We can't just do corrupt things, including potentially crashing, when the > configuration is wrong. We can't ensure that the configuration is accurate all > the time. So we need to detect this case. Hence needing to detect conflicts. >
OK. Got it, thanks. > > > IMHO even in normal scenarios i.e. when we are not doing LD on > > standby, we should mandate the use of a physical replication slot. > > I don't think that's going to fly. There plenty scenarios where you e.g. don't > want to use a slot, e.g. when you want to limit space use on the primary. > I think this can be controlled via max_slot_wal_keep_size GUC, if I understand it correctly. -- With Regards, Ashutosh Sharma.
