On Tue, Dec 23, 2025 at 7:18 PM Shlok Kyal <[email protected]> wrote: > > Hi Fujii-san, > > On Mon, 22 Dec 2025 at 22:57, Fujii Masao <[email protected]> wrote: > > > > Hi, > > > > While looking at subscription-related code, I noticed two issues related to > > version checks. > > > > if (walrcv_server_version(wrconn) < 19000) > > ereport(ERROR, > > errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), > > errmsg("cannot enable retain_dead_tuples if the > > publisher is running a version earlier than PostgreSQL 19")); > > > > First, in subscriptioncmds.c this check rejects enabling retain_dead_tuples > > when the publisher is running an older version. However, the comparison uses > > 19000 as v19 value. Since server versions are encoded as 190000 for v19, > > this appears to be a typo and allows the option to be enabled unexpectedly > > on pre-v19 publishers. The attached 0001 patch fixes this by correcting > > the version constant. > > > I tested this. I created a publisher in PG17 and tried creating > subscriber in PG19. > > Without Patch, I am able to create the subscription with > retain_dead_tuples = true. > postgres=# CREATE SUBSCRIPTION sub1 CONNECTION 'host=localhost > port=5432 dbname=postgres' PUBLICATION pub1 WITH (retain > _dead_tuples=true); > NOTICE: created replication slot "sub1" on publisher > CREATE SUBSCRIPTION > > With 0001 Patch, this issue is resolved. > postgres=# CREATE SUBSCRIPTION sub2 CONNECTION 'host=localhost > port=5432 dbname=postgres' PUBLICATION pub1 WITH > (retain_dead_tuples=true); > ERROR: cannot enable retain_dead_tuples if the publisher is running a > version earlier than PostgreSQL 19 > > > Second, CREATE SUBSCRIPTION with copy_data=true and origin='none' currently > > fails when the publisher is running a version earlier than v19, although > > this combination should be supported. The failure occurs because the command > > issues a query calling pg_get_publication_sequences on the publisher, > > which does not exist before v19. The attached 0002 patch fixes this > > by skipping that query when the publisher runs an older version. > > > I am able to reproduce this scenario. > I created a publisher in PG17 and tried creating subscriber in PG19. > > Without Patch we are hitting the following error. > postgres=# CREATE SUBSCRIPTION sub1 CONNECTION 'host=localhost > port=5432 dbname=postgres' PUBLICATION pub1 WITH (origin='none'); > ERROR: could not receive list of replicated sequences from the > publisher: ERROR: function pg_get_publication_sequences(name) does > not exist > LINE 3: LATERAL pg_get_publication_sequences(P.pubname) GPS > ^ > HINT: No function matches the given name and argument types. You > might need to add explicit type casts. > > And I confirm that the 0002 patch resolves this.
Thanks for the review and test! I've pushed the patches. Regards, -- Fujii Masao
