Re: Slot issues

Hi,

On 2018-10-15 03:18:35 +0530, bhargav kamineni wrote:
> > You probably afterwards want to drop those slots from the new standby.
> > See the following section from the docs:
>
> >
> https://www.postgresql.org/docs/current/static/continuous-archiving.html#BACKUP-LOWLEVEL-BASE-BACKUP-DATA
> "It is often a good idea to also omit from the backup the files within the
> cluster's pg_replslot/ directory, so that replication slots that exist on
> the master do not become part of the backup. Otherwise, the subsequent use
> of the backup to create a standby may result in indefinite retention of WAL
> files on the standby, and possibly bloat on the master if hot standby
> feedback is enabled, because the clients that are using those replication
> slots will still be connecting to and updating the slots on the master, not
> the standby. Even if the backup is only intended for use in creating a new
> master, copying the replication slots isn't expected to be particularly
> useful, since the contents of those slots will likely be badly out of date
> by the time the new master comes on line."
>
> Since i already synced the pg_repslot to standby ,Is it okay if i remove
> the pg_repslot directory befor starting postgresql service ?

You can do that, but the nicer way probably is to just remove them via
sql once started. Something like
SELECT pg_drop_replication_slot(slot_name) FROM pg_replication_slots;

Greetings,

Andres Freund