Re: Fix exclude generated columns in COPY TO with RLS

On 05/11/2026 12:34, Jim Jones wrote:

> It also changes how COPY TO handles columns that the user has no select privileges on,but
> I'd argue this is an improvement:
>
> create user u login;
> create table t(a int, b int generated always as (a+40) stored, c text);
> insert into t (a,c) values (2,'foo');
> grant select (a,c) on t to u;
> alter table t enable row level security;
> create policy p on t using (true);
>
> == master ==
>
> postgres=# set role u;
> SET
> postgres=> copy t to stdout;
> ERROR: permission denied for table t
>
> == patched ==
>
> postgres=# set role u;
> SET
> postgres=> copy t to stdout;
> 2 foo
> postgres=>
>
> I guess this test could also be added to the regression tests.
You're right! Done in v2.
> BTW, is there another reason to not allow generated columns in COPY TO
> other than being consistent with COPY FROM?
I don't see a reason other than having a consistent behavior for a round
trip of COPY TO/FROM (It makes sense though...)
At least for users who insist on emitting them in output, they can still
do something like COPY (SELECT * FROM t) TO ...

Thanks for the review Jim.

Regards,
Ayoub Kazar