Re: [ADMIN] Replication slots and isolation levels

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. I guess that's the
origin of your confusion:
http://www.postgresql.org/message-id/20150616192141.GD2626@alap3.anarazel.de
--
Michael