On 11/19/18 04:46, Tom Lane wrote:
> In short, proceeding like the above when we can't find another plan
> type for a full join seems like it fixes a far wider variety of cases.
> The possibility that maybe we could do some of those cases a bit faster
> isn't sufficiently attractive to me to justify also putting in a
> mechanism like this patch proposes.  We only rarely see complaints at
> all about can't-do-a-full-join problems, and I do not think this patch
> would fix enough of those complaints to be worthwhile.
I agree, the automated UNION substitutions seems to be a better 
approach. I'll mark this patch as rejected then.
-- 
Alexander Kuzmenkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company