Horton

Re: Significant Execution Time Difference Between PG13.14 and PG16.4 for Query on information_schema Tables.

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Justin Clift <justin@postgresql.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, nikhil raj <nikhilraj474@gmail.com>, "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>, NIKITA PATEL <patelnikita1411@gmail.com>, Patel Khushbu <patelkhushbu2067@gmail.com>
Date: 2024-08-27T10:14:07Z
Lists: pgsql-hackers, pgsql-general 
On Tue, 27 Aug 2024 at 18:00, Justin Clift <justin@postgresql.org> wrote:
> As a general thought, seeing that this might be an actual problem
> should some kind of automated testing be added that checks for
> performance regressions like this?

We normally try to catch these sorts of things with regression tests.
Of course, that requires having a test that would catch a particular
problem, which we don't seem to have for this particular case.  A
performance test would also require testing a particular scenario, so
I don't see why that's better.  A regression test is better suited as
there's no middle ground between pass and fail.

David

Commits

  1. Avoid inserting PlaceHolderVars in cases where pre-v16 PG did not.

  2. Remove one memoize test case added by commit 069d0ff02.