From: | Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> |
---|---|
To: | Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com> |
Cc: | Andreas Seltenreich <seltenreich(at)gmx(dot)de>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [sqlsmith] Failed assertion in postgres_fdw/deparse.c:1116 |
Date: | 2016-06-07 10:37:09 |
Message-ID: | 03c2d391-18ad-bf4e-1323-f5ab93e1b6ee@lab.ntt.co.jp |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 2016/06/07 19:13, Ashutosh Bapat wrote:
> I thought, columns of inner relation will be set to null during projection
> from ForeignScan for joins. But I was wrong. If we want to push-down joins
> in this case, we have two solutions
> 1. Build queries with subqueries at the time of deparsing. Thus a base
> relation or join has to include placeholders while being deparsed as a
> subquery. This means that the deparser should deparse expression
> represented by the placeholder. This may not be possible always.
> 2. At the time of projection from ForeignScan recognize the nullable
> placeholders and nullify them if the corresponding relation is nullified.
> That looks like a major surgery.
> So, your patch looks to be the correct approach (even after we support
> deparsing subqueries). Can you please include a test in regression?
I added a slightly modified version of your test to the originally posted
patch.
Thanks,
Amit.
Attachment | Content-Type | Size |
---|---|---|
pgfdw-join-pd-bug-2.patch | text/x-diff | 3.3 KB |
From | Date | Subject | |
---|---|---|---|
Next Message | Andreas Karlsson | 2016-06-07 10:41:17 | Re: slower connect from hostnossl clients |
Previous Message | Magnus Hagander | 2016-06-07 10:18:31 | Re: slower connect from hostnossl clients |