Horton

Re: [HACKERS] postgres_fdw bug in 9.6

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, Jeff Janes <jeff.janes@gmail.com>, David Steele <david@pgmasters.net>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-01-19T15:17:53Z
Lists: pgsql-hackers 
On Fri, Jan 19, 2018 at 1:53 AM, Etsuro Fujita
<fujita.etsuro@lab.ntt.co.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
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix test case for 'outer pathkeys do not match mergeclauses' fix.

  2. postgres_fdw: Avoid 'outer pathkeys do not match mergeclauses' error.

  3. postgres_fdw: Consider foreign joining and foreign sorting together.

  4. Allow foreign and custom joins to handle EvalPlanQual rechecks.

  5. Allow FDWs to push down quals without breaking EvalPlanQual rechecks.