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In-Reply-To: <ba5eaa35-cd85-43d6-95b3-8cf211fd6b67@postgrespro.ru>
From: jian he <jian.universality@gmail.com>
Date: Wed, 21 May 2025 22:54:48 +0800
Message-ID: 
 <CACJufxE9FDqaE=xbxT-Ujk_G=wW-PeW0TrOB11E8n3-A+FP-GA@mail.gmail.com>
Subject: Re: Add SPLIT PARTITION/MERGE PARTITIONS commands
To: Dmitry Koval <d.koval@postgrespro.ru>
Cc: pgsql-hackers@lists.postgresql.org
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On Wed, May 21, 2025 at 8:30=E2=80=AFPM Dmitry Koval <d.koval@postgrespro.r=
u> wrote:
>
> Hi!
>
>  >per https://www.postgresql.org/docs/current/sql-altertable.html
>  >"You must own the table to use ALTER TABLE."
>  >That means the current user must own the to be SPLITed partition.
>
> Last statement may be incorrect (if the logic is different).
> Current user can attach another user's partition. If current user can
> change (attach) another user's partition, why can't he split the
> partition? After attach, partition is part of current user's table, and
> current user can change his own table. (Moreover, the owner of the new
> partitions is the same as the owner of the split partition.)
>
> --

I think if he can attach another partition, then he can split the partition=
.
currently ALTER TABLE ATTACH PARTITION requires the current user
both own the partitioned table and the to be attached partition.

for example:

begin;
create role alice;
create role bob;
GRANT all privileges on schema public to alice;
GRANT all privileges on schema public to bob;
set role bob;
create table at_partitioned (a int, b text) partition by range (a);
set role alice;
create table at_part_2 (b text, a int);
set role bob;
alter table at_partitioned attach partition at_part_2 for values from
(1000) to (2000); --should error
rollback;

----------------
begin;
create role alice;
create role bob;
GRANT all privileges on schema public to alice;
GRANT all privileges on schema public to bob;
set role bob;
create table at_partitioned (a int, b text) partition by range (a);
set role alice;
create table at_part_2 (b text, a int);
alter table at_partitioned attach partition at_part_2 for values from
(1000) to (2000); --should error
rollback;


P.S. maybe using sql examples can illustrate the idea more intuitively,
sometimes words may cause confusion.