Re: Foreign join pushdown vs EvalPlanQual - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Foreign join pushdown vs EvalPlanQual
Date
Msg-id CA+TgmoY5Lf+vYy1Bha=U7__S3qtMQP7d+gSSfd+LN4Xz6Fybkg@mail.gmail.com
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In response to Re: Foreign join pushdown vs EvalPlanQual  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
Responses Re: Foreign join pushdown vs EvalPlanQual  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
List pgsql-hackers
On Tue, Nov 3, 2015 at 8:15 AM, Kouhei Kaigai <kaigai@ak.jp.nec.com> wrote:
> A challenge is that junk wholerow references on behalf of ROW_MARK_COPY
> are injected by preprocess_targetlist(). It is earlier than the main path
> consideration by query_planner(), thus, it is not predictable how remote
> query shall be executed at this point.

Oh, dear.  That seems like a rather serious problem for my approach.

> If ROW_MARK_COPY, base tuple image is fetched using this junk attribute.
> So, here is two options if we allow to put joined tuple on either of
> es_epqTuple[].

Neither of these sounds viable to me.

I'm inclined to go back to something like what you proposed here:

http://www.postgresql.org/message-id/9A28C8860F777E439AA12E8AEA7694F80114B89D@BPXM15GP.gisp.nec.co.jp

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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