On 4/7/25 13:32, Willy-Bas Loos wrote:
Hi Laurenz,
Thanks for answering!
I find it very strange, because the publication is needed to make a
subscription, which makes the slot.
From here:
https://www.postgresql.org/docs/current/logical-replication-subscription.html
"A subscription defines the connection to another database and set of
publications (one or more) to which it wants to subscribe."
and here:
"PUBLICATION publication_name [, ...]
Names of the publications on the publisher to subscribe to.
"
Finding the subscriptions for a given publication and deleting those
slots may break the subscription on the receiving side if it is looking
for data from more then one publication.
Thanks for looking into it and helping me understand.
Cheers!
Willy-Bas Loos
On Mon, Apr 7, 2025 at 3:31 PM Laurenz Albe <laurenz.a...@cybertec.at
<mailto:laurenz.a...@cybertec.at>> wrote:
On Mon, 2025-04-07 at 12:16 +0200, Willy-Bas Loos wrote:
> My question is not so much about "can i drop a certain
replication slot",
> more about "does this publication still have any replication slots?".
> Or, if you will: "what's the publication for this replication slot?".
>
> I've double checked the views that you suggested, and I found
that I can relate
> the WAL sender processes to replication slots through
pg_replication_slots.active_pid .
> I've also looked into replication origins.
>
> But I can't find a link to the publication. And that's what I
need to know.
I don't think that there is a connection between a publication and a
replication slot. That connection is only made when a subscriber
connects
and runs the START_REPLICATION command [1] and specifies the "pgoutput"
plugin with the "publication_names" option [2].
I don't think you can see that information reflected in a system view
on the primary. You'd have to query "pg_subscription" on the standby.
Yours,
Laurenz Albe
[1]:
https://www.postgresql.org/docs/current/protocol-replication.html#PROTOCOL-REPLICATION-START-REPLICATION-SLOT-LOGICAL
<https://www.postgresql.org/docs/current/protocol-replication.html#PROTOCOL-REPLICATION-START-REPLICATION-SLOT-LOGICAL>
[2]:
https://www.postgresql.org/docs/current/protocol-logical-replication.html#PROTOCOL-LOGICAL-REPLICATION-PARAMS
<https://www.postgresql.org/docs/current/protocol-logical-replication.html#PROTOCOL-LOGICAL-REPLICATION-PARAMS>
--
Willy-Bas Loos
--
Adrian Klaver
adrian.kla...@aklaver.com
