Thread

1. Document COPY FROM WHERE restrictions on generated and system columns

   Fujii Masao <masao.fujii@gmail.com> — 2026-06-25T16:46:41Z

   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?
   
   Regards,
   
   -- 
   Fujii Masao
   

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

   Ayush Tiwari <ayushtiwari.slg01@gmail.com> — 2026-07-02T13:16:41Z

   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
   

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

   Fujii Masao <masao.fujii@gmail.com> — 2026-07-08T03:48:31Z

   On Thu, Jul 2, 2026 at 10:16 PM Ayush Tiwari
   <ayushtiwari.slg01@gmail.com> wrote:
   > Thanks for the patch!
   >
   > I think it makes sense to add the system columns and generated
   > columns limitation to the documentation, patch LGTM.
   
   Thanks for the review! I've pushed the patch.
   
   Regards,
   
   -- 
   Fujii Masao