On Tue, Oct 27, 2020 at 10:23 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> This patch looks reasonable to me at a quick glance. I'm a bit worried
> or unhappy about the impact on FDWs, though. It doesn't seem nice that
> the ResultRelInfo is not available in the BeginDirectModify call. It's
> not too bad, the FDW can call ExecGetResultRelation() if it needs it,
> but still. Perhaps it would be better to delay calling
> BeginDirectModify() until the first modification is performed, to avoid
> any initialization overhead there, like establishing the connection in
> postgres_fdw.
Ah, calling BeginDirectModify() itself lazily sounds like a good idea;
see attached updated 0001 to see how that looks. While updating that
patch, I realized that the ForeignScan.resultRelation that we
introduced in 178f2d560d will now be totally useless. :-(
--
Amit Langote
EDB: http://www.enterprisedb.com