Horton

Re: print_path is missing GatherMerge and CustomScan support

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
Date: 2018-07-19T06:26:50Z
Lists: pgsql-hackers 
On Thu, Jul 19, 2018 at 10:41:10AM +0530, Ashutosh Bapat wrote:
> I had extensive testcases in my original patch-set to exercise that
> code but 1. that testset was too extensive; even today
> partition_join.sql is a separate testcase and it's quite large. 2.
> that function returns NULL rather than throwing an error, if it can
> not produce a parameterized path. So, unless we check whether each of
> those paths get created no test is useful and that can only be done
> through an EXPLAIN OUTPUT which means that the testcase becomes
> fragile. I fine if we want to add more tests just to cover the code if
> those are not as fragile and do not blow up partition_join too much.

Did those really check the reparameterization of a MergeAppendPath for a
child of the parent?  I'd be surprised if this one was stressed as there
was no match in the list.
--
Michael

Commits

  1. Fix print of Path nodes when using OPTIMIZER_DEBUG

  2. Fix re-parameterize of MergeAppendPath