Horton

Re: BUG #16583: merge join on tables with different DB collation behind postgres_fdw fails

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Etsuro Fujita <etsuro.fujita@gmail.com>
Cc: Ibrar Ahmed <ibrar.ahmad@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Neil Chen <carpenter.nail.cz@gmail.com>
Date: 2021-09-01T20:42:49Z
Lists: pgsql-bugs, pgsql-hackers

Attachments

Etsuro Fujita <etsuro.fujita@gmail.com> writes:
> On Thu, Jul 15, 2021 at 4:17 AM Ibrar Ahmed <ibrar.ahmad@gmail.com> wrote:
>> On Wed, Jul 14, 2021 at 1:41 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Seems to just need an update of the expected-file to account for test
>>> cases added recently.  (I take no position on whether the new results
>>> are desirable; some of these might be breaking the intent of the case.
>>> But this should quiet the cfbot anyway.)

>> The test case was added by commit "Add support for asynchronous execution"
>> "27e1f14563cf982f1f4d71e21ef247866662a052" by Etsuro Fujita. He can comment
>> whether the new results are desirable or not.

> The new results aren't what I intended.  I'll update the patch to
> avoid that by modifying the original test cases properly, if there are
> no objections.

Please follow up on that sometime?  In the meantime, here is a rebase
over aa769f80e and 2dc53fe2a, to placate the cfbot.

The real reason that this hasn't gotten committed is that I remain
pretty uncomfortable about whether it's an acceptable solution to
the problem.  Suddenly asking people to plaster COLLATE clauses
on all their textual remote columns seems like a big compatibility
gotcha.  However, I lack any ideas about a less unpleasant solution.

			regards, tom lane

Commits

  1. Doc: extend warnings about collation-mismatch hazards in postgres_fdw.

  2. Add support for asynchronous execution.

  3. Suppress unnecessary RelabelType nodes in yet more cases.