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From: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Joe Conway <mail@joeconway.com>
Cc: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Cc: Rushabh Lathia <rushabh.lathia@gmail.com>
Cc: Michael Paquier <michael.paquier@gmail.com>
Subject: Re: postgres_fdw: perform UPDATE/DELETE .. RETURNING on a join directly
Date: Mon, 09 Apr 2018 19:15:28 +0900
Message-ID: <5ACB3D40.4040304@lab.ntt.co.jp> (raw)
In-Reply-To: <20180406191747.4dwggard7beyfkps@alap3.anarazel.de>
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	<20180406191747.4dwggard7beyfkps@alap3.anarazel.de>

(2018/04/07 4:17), Andres Freund wrote:
> On 2018-03-05 17:07:10 -0500, Tom Lane wrote:
>> Meanwhile, I'm back to wondering what could possibly have affected
>> the planner's estimates, if pg_proc and pg_statistic didn't change.
>> I confess bafflement ... but we've now eliminated the autovacuum-
>> did-it theory entirely, so it's time to start looking someplace else.
>> I wonder if something in the postgres_fdw remote join machinery
>> is not as deterministic as it should be.
>
> I wonder if temporarily changing postgres_fdw's test to specify an extra
> config that installs auto_explain in full aggressiveness (i.e. including
> costs etc) and enables debug3 logging could help narrow this down?

+1 because we cannot deny the possibility that the plan instability is 
caused by such an unexpected behavior of postgres_fdw.

Best regards,
Etsuro Fujita




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  To: pgsql-hackers@postgresql.org
  Cc: fujita.etsuro@lab.ntt.co.jp, andres@anarazel.de, tgl@sss.pgh.pa.us, mail@joeconway.com, ashutosh.bapat@enterprisedb.com, robertmhaas@gmail.com, rushabh.lathia@gmail.com, michael.paquier@gmail.com
  Subject: Re: postgres_fdw: perform UPDATE/DELETE .. RETURNING on a join directly
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