BUG #18683: A publication must be created *before* a logical rep slot in order to be used with that slot? - Mailing list pgsql-bugs

From PG Bug reporting form
Subject BUG #18683: A publication must be created *before* a logical rep slot in order to be used with that slot?
Date
Msg-id 18683-a98f79c0673be358@postgresql.org
Whole thread Raw
Responses Re: BUG #18683: A publication must be created *before* a logical rep slot in order to be used with that slot?
Re: BUG #18683: A publication must be created *before* a logical rep slot in order to be used with that slot?
List pgsql-bugs
The following bug has been logged on the website:

Bug reference:      18683
Logged by:          Anthony Accomazzo
Email address:      accomazz@gmail.com
PostgreSQL version: 17.0
Operating system:   MacOS 15.0.1 (Sequoia)
Description:

It seems that if you (1) create a logical replication slot (2) and activity
happens in your database then (3) you create a publication, the combination
of that slot + publication is not usable (you can't connect).

i.e. if there is any activity "in" a slot that predates the create statement
for a pub, the slot+pub combo will not work.

Is this known behavior? It's surprising just insofar as I'd hope either:

- the docs cover this
- the error message that one gets could be made clearer

Reproduction steps:

```
create table public.mytable (
    id serial primary key,
    inserted_at timestamp default now(),
    updated_at timestamp default now()
);

create table public.mytable2 (
    id serial primary key,
    inserted_at timestamp default now(),
    updated_at timestamp default now()
);

-- ensure clean start
drop publication test_pub;
select pg_drop_replication_slot('test_slot');

-- create the slot
select pg_create_logical_replication_slot('test_slot', 'pgoutput');
-- insert into any table
insert into mytable2 (id) values (default);
-- create a pub
create publication test_pub for table mytable;
-- cannot connect to slot

-- in shell:
$ pg_recvlogical -d
postgresql://postgres:postgres@localhost:5432/sequin_dev_rep --slot
test_slot --start -o proto_version=1 -o publication_names='test_pub' -f -

pg_recvlogical: error: unexpected termination of replication stream: ERROR:
publication "test_pub" does not exist
CONTEXT:  slot "test_slot", output plugin "pgoutput", in the change
callback, associated LSN A/7D3CD9F0
pg_recvlogical: disconnected; waiting 5 seconds to try again
pg_recvlogical: error: unexpected termination of replication stream: ERROR:
publication "test_pub" does not exist
```


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