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Date: Thu, 12 Feb 2026 11:36:26 -0300
Message-Id: <DGD24UA7LASG.11H30IV2AFVA2@gmail.com>
Cc: "Matheus Alcantara" <matheusssilv97@gmail.com>
Subject: Re: COMMENTS are not being copied in CREATE TABLE LIKE
From: "Matheus Alcantara" <matheusssilv97@gmail.com>
To: "Jim Jones" <jim.jones@uni-muenster.de>,
 "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
References: <e08cb97f-0364-4002-9cda-3c16b42e4136@uni-muenster.de>
In-Reply-To: <e08cb97f-0364-4002-9cda-3c16b42e4136@uni-muenster.de>
Archived-At: <https://www.postgresql.org/message-id/DGD24UA7LASG.11H30IV2AFVA2%40gmail.com>
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Hi, thanks for checking this.

On Thu Feb 12, 2026 at 7:11 AM -03, Jim Jones wrote:
> Hi,
>
> While reviewing another patch[1] I saw that COMMENTS on tables are being
> ignored in CREATE TABLE LIKE:
>
> psql (18.1 (Debian 18.1-1.pgdg13+2))
> Type "help" for help.
>
> postgres=3D# \pset null '(null)'
> Null display is "(null)".
> postgres=3D# CREATE TABLE t1 (id int, name text);
> COMMENT ON TABLE t1 IS 'table comment';
> CREATE TABLE t2 (LIKE t1 INCLUDING ALL);
> CREATE TABLE t3 (LIKE t1 INCLUDING COMMENTS);
>
> SELECT
>   obj_description('t1'::regclass, 'pg_class') AS t1_comment,
>   obj_description('t2'::regclass, 'pg_class') AS t2_comment,
>   obj_description('t3'::regclass, 'pg_class') AS t3_comment;
> CREATE TABLE
> COMMENT
> CREATE TABLE
> CREATE TABLE
>   t1_comment   | t2_comment | t3_comment
> ---------------+------------+------------
>  table comment | (null)     | (null)
> (1 row)
>
>
> v1 attached attempts to fix it by expanding expandTableLikeClause() to
> retrieve and copy the table-level comment when the INCLUDING COMMENTS
> [ALL] option is specified:
>

The patch fix the issue and it seems correct to me.

This bug seems to also happen on 14.20:
postgres=3D# select version();
                                                           version
---------------------------------------------------------------------------=
---------------------------------------------------
 PostgreSQL 14.20 (Homebrew) on aarch64-apple-darwin24.6.0, compiled by App=
le clang version 17.0.0 (clang-1700.4.4.1), 64-bit
(1 row)

postgres=3D# CREATE TABLE t(a int, b text);
CREATE TABLE
postgres=3D# COMMENT ON TABLE t IS 'foo';
COMMENT
postgres=3D# CREATE TABLE t2(LIKE t INCLUDING ALL);
CREATE TABLE
postgres=3D# SELECT obj_description('t'::regclass, 'pg_class') as t_comment=
, obj_description('t2'::regclass, 'pg_class') AS t2_comment;
 t_comment | t2_comment
-----------+------------
 foo       |
(1 row)

So I think that we need to backport.

--
Matheus Alcantara
EDB: https://www.enterprisedb.com