On Mon, Jan 15, 2018 at 3:09 AM, Etsuro Fujita
<fujita.etsuro@lab.ntt.co.jp> wrote:
> Yeah, but I don't think the above example is good enough to explain that,
> because I think the bar/baz join would produce at most one tuple in an EPQ
> recheck since we would have only one EPQ tuple for both bar and baz in that
> recheck, and the join is inner. I think such an example would probably be
> given e.g., by a modified version of the SQL where we have a full join of
> bar and baz, not an inner join.
Hmm, I was thinking that bar and baz wouldn't be constrained to return
just one tuple in that case, but I'm wrong: there would just be one
tuple per relation in that case. However, that would also be true for
a full join, wouldn't it?
Regardless of that, the patch fixes the reported problem with very
little code change, and somebody can always improve it further later.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company