Re: [HACKERS] DROP SUBSCRIPTION, query cancellations and slot handling

On Thu, Apr 20, 2017 at 4:22 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> I am adding an open item.

Just adding something... When a subscription is created, if the step
synchronizing tables fails then CREATE SUBSCRIPTION fails but the slot
remains present on the publisher side, so trying to re-create the same
subscription results in an error:

=# CREATE SUBSCRIPTION mysub CONNECTION 'port=5432' PUBLICATION mypub,
insert_only;
NOTICE:  00000: Sleeping now...
NOTICE:  00000: created replication slot "mysub" on publisher
LOCATION:  CreateSubscription, subscriptioncmds.c:411
ERROR:  42P01: relation "public.aa" does not exist
LOCATION:  RangeVarGetRelidExtended, namespace.c:400
Time: 1033.739 ms (00:01.034)
=# CREATE SUBSCRIPTION mysub CONNECTION 'port=5432 user=mpaquier
dbname=mpaquier' PUBLICATION mypub, insert_only;
NOTICE:  00000: Sleeping now...
LOCATION:  CreateSubscription, subscriptioncmds.c:376
ERROR:  XX000: could not create replication slot "mysub": ERROR:
replication slot "mysub" already exists
LOCATION:  libpqrcv_create_slot, libpqwalreceiver.c:776

I have created a simple table aa (a int) on the publisher first, where
a publication with ALL TABLES has been created:
CREATE PUBLICATION mypub FOR ALL TABLES;
-- 
Michael