Thread: Re: Prevent COPY FREEZE on Foreign tables

On Mon, Feb 03, 2025 at 02:18:21PM -0600, Sami Imseih wrote:
> I think we should just block Foreign tables as we do with
> partition tables. Attached patch does that.

Unless there's some existing way to specify a FREEZE option in the FDW API
(I assume there isn't), I agree with this.

> I was also looking at why we block a parent from COPY FREEZE[1], but
> the comments do not convince me this is a good idea. I think there
> are good cases to allow this considering there is a common use case in
> which a single
> COPY command can load a large amount of data, making the overhead to check the
> partitions worth the value of the FREEZE optimization. I will probably
> start a separate thread for this.

Commit 5c9a551 and its thread [0] appear to have some additional details
about this.

[0] https://postgr.es/m/CAKJS1f9BbJ%2BFY3TbdCiap3qXHTFOiwtays9s36-oQkkM9_R5bg%40mail.gmail.com

-- 
nathan

> Unless there's some existing way to specify a FREEZE option in the FDW API
> (I assume there isn't), I agree with this.

I am not aware of any way to do this either as postgres_fdw is simply
using libpq.

> > I was also looking at why we block a parent from COPY FREEZE[1], but

> Commit 5c9a551 and its thread [0] appear to have some additional details
> about this.
>
> [0] https://postgr.es/m/CAKJS1f9BbJ%2BFY3TbdCiap3qXHTFOiwtays9s36-oQkkM9_R5bg%40mail.gmail.com

Thanks for the thread. I will go through it.
I did not too much investigation here yet but I can imagine this might
be a worthwhile
to see the possibility to remove this limitation on a partitioned table.

Regards,

Sami