Horton

Re: [HACKERS] postgres_fdw bug in 9.6

Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>

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From: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
To: Robert Haas <robertmhaas@gmail.com>
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: 2018-01-19T06:53:12Z
Lists: pgsql-hackers

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(2018/01/18 15:40), Etsuro Fujita wrote:
> (2018/01/18 7:09), Robert Haas wrote:
>> On Wed, Jan 17, 2018 at 4:08 PM, Tom Lane<tgl@sss.pgh.pa.us> wrote:
>>> It's debatable perhaps -- I tend to err in the other direction.
>>> But likewise, I don't care deeply. Just push it ...
>>
>> Done.

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.

Best regards,
Etsuro Fujita

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.