Thread

Re: [PATCH] Preserve replication origin OIDs in pg_upgrade

shveta malik <shveta.malik@gmail.com> — 2026-05-25T07:13:27Z

On Fri, May 22, 2026 at 3:57 PM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Fri, May 22, 2026 at 3:16 PM Shlok Kyal <shlok.kyal.oss@gmail.com> wrote:
> >
> > On Mon, 18 May 2026 at 16:13, Ajin Cherian <itsajin@gmail.com> wrote:
> > >
> > > Rebased the patch as it was no longer applying.
> > >
> > Hi Ajin,
> >
> > I have started reviewing the patch. Here is my comment for v6-0002 patch:
> >
> > Suppose we have a replication setup: publisher -> subscriber
> > and we are upgrading subscriber to subscriber_new.
> > And if initially 'subscriber_new' has a replication origin, upgrading
> > the cluster can error out.
> >
> > Example:
> > We set up a logical replication between publisher node and subscriber node.
> >
> > On subscriber node:
> > postgres=# SELECT * FROM pg_replication_origin;
> >  roident |  roname
> > ---------+----------
> >        1 | pg_16393
> > (1 row)
> >
> > And initially subscriber_new has a replication origin:
> > postgres=# select pg_replication_origin_create('myname');
> >  pg_replication_origin_create
> > ------------------------------
> >                             1
> > (1 row)
> >
> > postgres=# SELECT * FROM pg_replication_origin;
> >  roident | roname
> > ---------+--------
> >        1 | myname
> > (1 row)
> >
> > Now, if we run pg_upgrade to upgrade subscriber node to subscriber_new
> > node, we get an error:
> > ```
> > SELECT pg_catalog.binary_upgrade_create_replication_origin('1'::pg_catalog.oid,
> > 'pg_16393'::pg_catalog.name, '0/01743078'::pg_catalog.pg_lsn);
> > psql:subscriber_new/pg_upgrade_output.d/20260522T140312.807/dump/pg_upgrade_dump_globals.sql:37:
> > ERROR:  replication origin with ID 1 already exists
> > ```
> >
> > This error occurs in "Performing Upgrade" stage. Should we add a check
> > in the "Performing Consistency Checks" stage so that we don't need to
> > re-initdb the new cluster to perform the upgrade?
> > Maybe we can add a check similar to
> > check_new_cluster_replication_slots(), where pg_upgrade errors out if
> > the new cluster already contains replication origins. Thoughts?
>
> +1. I had the same thought while reviewing the patch today. We should
> have it unless there is a reason we have avoided it??
>
> Few trivial comments:
>
> 1)
>
> +#include "access/skey.h"
> +#include "catalog/indexing.h"
>
> pg_upgrade_support.c compiles without above.
>
> 2)
> + Assert(!OidIsValid(rel->rd_rel->reltoastrelid));
>
> Is there a reason for this sanity check? I generally do not see a
> Null-Toast table sanity check after every table_open.
>
> 3)
>
> +
> + /* Dump replication origins */
> + if (server_version >= 170000 && binary_upgrade && archDumpFormat == archNull)
> + dumpReplicationOrigins(conn);
>
> why the check is for PG17 specifically?
>

One issue in 002:

binary_upgrade_create_replication_origin() has this:

+ originname = PG_GETARG_NAME(1);
+
+ roname_d = CStringGetTextDatum(NameStr(*originname));
+

We are getting origin-name (text) into Name-type which can not be more
than 64 bytes. So if an origin has name more than 64, it will end up
trimming the name post-upgrade.

I tried this:

Old-setup:
postgres=# SELECT
pg_replication_origin_create('this_is_a_very_long_replication_origin_name_that_exceeds_the_limit_of_64');
 pg_replication_origin_create
------------------------------
                            1
postgres=# select * from pg_replication_origin;
 roident |                                roname
---------+----------------------------------------------------------------------
       1 | this_is_a_very_long_replication_origin_name_that_exceeds_the_limit_of_64


Post-upgrade: name got trimmed to 64 length.
-------------------------
postgres=#  select * from pg_replication_origin;
 roident |                             roname
---------+-----------------------------------------------------------------
       1 | this_is_a_very_long_replication_origin_name_that_exceeds_the_li

thanks
Shveta