Horton

Re: using index or check in ALTER TABLE SET NOT NULL

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Sergei Kornilov <sk@zsrv.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, David Steele <david@pgmasters.net>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Stephen Frost <sfrost@snowman.net>, Ildar Musin <i.musin@postgrespro.ru>
Date: 2019-06-11T20:34:57Z
Lists: pgsql-hackers 
On Tue, 11 Jun 2019 at 03:35, Sergei Kornilov <sk@zsrv.org> wrote:
> > Does anyone think we shouldn't change the INFO message in ATTACH
> > PARTITION to a DEBUG1 in PG12?
>
> Seems no one wants to vote against this change.

I'm concerned about two things:

1. The patch reduces the test coverage of ATTACH PARTITION. We now
have no way to ensure the constraint was used to validate the rows in
the partition.
2. We're inconsistent with what we do for SET NOT NULL and ATTACH
PARTITION. We raise an INFO message when we use a constraint for
ATTACH PARTITION and only a DEBUG1 for SET NOT NULL.

Unfortunately, my two concerns conflict with each other.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Avoid using INFO elevel for what are fundamentally debug messages.

  2. Revert setting client_min_messages to 'debug1' in new tests.

  3. Allow ALTER TABLE .. SET NOT NULL to skip provably unnecessary scans.

  4. Improve predtest.c's internal docs, and enhance its functionality a bit.