Re: Custom Scan APIs (Re: Custom Plan node)

On Wed, Feb 26, 2014 at 10:23 AM, Stephen Frost <sfrost@snowman.net> wrote:
> * Kouhei Kaigai (kaigai@ak.jp.nec.com) wrote:
>> IIUC, his approach was integration of join-pushdown within FDW APIs,
>> however, it does not mean the idea of remote-join is rejected.
>
> For my part, trying to consider doing remote joins *without* going
> through FDWs is just nonsensical.

That is, of course, true by definition, but I think it's putting the
focus in the wrong place.  It's possible that there are other cases
when a scan might a plausible path for a joinrel even if there are no
foreign tables in play.  For example, you could cache the joinrel
output and then inject a cache scan as a path for the joinrel.

-- 
Robert Haas
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