On Saturday, March 29, 2025, Kirill Reshke <
reshkekirill@gmail.com> wrote:
On Sat, 29 Mar 2025 at 09:47, jian he <jian.universality@gmail.com> wrote:
>
> will use {table_beginscan, table_scan_getnextslot, table_endscan}
> to output the data.
> but views don't have storage, table_beginscan mechanism won't work.
>
> so i don't think this is possible for view.
Well... So you are saying that let us have inconsistent features
because of how things are implemented in core... I don't sure I'm
buying that, but whatever, let's hear some other voices from the
community. My argument is that while we are working on it, perhaps we
should revise certain implementation specifics along the way. However,
this is merely my opinion on the matter.
At present copy {table} to only exists to support pg_dump. It is not marketed as a general purpose export facility. While copy {relation} from is a general purpose importer. Do we want to turn copy to into a general purpose exporter and start accepting patches to export foreign tables, deal with partitioned tables, views of both kinds? Given we already accept things in copy from that copy to cannot produce the symmetry argument seems flawed.
I’m on board with making copy {relation} to a general purpose export facility and allowing for incremental implementations as people wish to spend time developing them. Consistency should not prevent progress here.
On the topic of copy {matview} from, why not permit it? In particular, with dump/restore we could dump the materialized view and restore it, which seems like a win in terms of time spent restoring. That wouldn’t be this patch.
David J.
