Re: Document COPY FROM WHERE restrictions on generated and system columns

Hi,

On Thu, 2 Jul 2026 at 18:41, Fujii Masao <masao.fujii@gmail.com> wrote:

> Hi,
>
> I found that generated columns and system columns cannot be used in
> COPY FROM WHERE expressions, but the COPY docs still mentions
> only the restriction on subqueries.
>
> So I've created the attached patch which updates the docs to also list
> generated columns and system columns as unsupported in COPY FROM WHERE
> expressions.
>
> Since generated columns have been rejected in COPY FROM WHERE since
> v13, that docs change should be backpatched to all supported branches.
> But the system-column restriction was introduced in v19, so that part
> does not need to be backpatched.
>
> Thoughts?
>

Thanks for the patch!

I think it makes sense to add the system columns and generated
columns limitation to the documentation, patch LGTM.

Regards,
Ayush