On 2015-10-30 13:42:19 +0100, Michael Paquier wrote: > On Fri, Oct 30, 2015 at 12:40 PM, Vladimir Borodin wrote: > > On Thu, Oct 29, 2015 at 3:29 PM, Oleksii Kliukin wrote: > >> Could it be a consequence of how REPEATABLE READ transactions handle > >> snapshots? With REPEATABLE READ the snapshot is acquired only once at the > >> beginning of a transaction; a READ COMMITTED transaction re-evaluates its > >> snapshot with each new command. > > > > I still don’t fully understand why is it so (the problem occurs while > > running only one SELECT-statement in READ COMMITED so only one snapshot is > > taken), but if is expected behavior shouldn’t the documentation mention that > > using READ COMMITTED (which is the default) you may still get conflicts with > > recovery while using replication slots? > > Replication slots and hot_standby_feedback are two different unrelated > concepts, slots being aimed at retaining WAL. Uh. Slots also retain the xmin horizon if hot_standby_feedback is enabled on the standby? > I guess that's the origin of your confusion: > http://www.postgresql.org/message-id/20150616192141.GD2626@xxxxxxxxxxxxxxxxx That just says what I said above, I don't see how this makes replication slots and hs feedback unrelated? Greetings, Andres Freund -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
