Re: [HACKERS] postgres_fdw bug in 9.6

On Fri, Jan 19, 2018 at 1:53 AM, Etsuro Fujita
<fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> I noticed that this test case added by the patch is not appropriate:
>
> +-- multi-way join involving multiple merge joins
> +EXPLAIN (VERBOSE, COSTS OFF)
> +SELECT * FROM ft1, ft2, ft4, ft5 WHERE ft1.c1 = ft2.c1 AND ft1.c1 = ft4.c1
> + AND ft1.c1 = ft5.c1 FOR UPDATE;
> +SELECT * FROM ft1, ft2, ft4, ft5 WHERE ft1.c1 = ft2.c1 AND ft1.c1 = ft4.c1
> + AND ft1.c1 = ft5.c1 FOR UPDATE;
>
> because it doesn't inject extra Sort nodes into EPQ recheck plans, so it
> works well without the fix. I modified this to inject a Sort into the
> recheck plan of the very first foreign join. Attached is a patch for that.

Mumble. Tom provided me with that example and said it failed without
the patch. I didn't check, I just believed him. But I'm surprised if
he was wrong; Tom usually tries to avoid being wrong...

--
Robert Haas
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