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: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Sergei Kornilov <sk@zsrv.org>, 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: 2019-05-02T02:22:59Z
Lists: pgsql-hackers 
On Thu, 2 May 2019 at 13:08, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> David Rowley <david.rowley@2ndquadrant.com> writes:
> > On Thu, 2 May 2019 at 06:18, Sergei Kornilov <sk@zsrv.org> wrote:
> >> PS: not think this is blocker for v12
>
> > Probably not a blocker, but now does not seem like an unreasonable
> > time to lower these INFO messages down to DEBUG.
>
> Not a blocker perhaps, but it's better if we can get new behavior to
> be more or less right the first time.

It's not really new behaviour though. The code in question is for
ATTACH PARTITION and was added in c31e9d4bafd (back in 2017).
bbb96c3704c is the commit for using constraints to speed up SET NOT
NULL. The mention of using the constraint for proof was made DEBUG1 in
the initial commit.  What we need to decide is if we want to make
ATTACH PARTITION's INFO message a DEBUG1 in pg12 or not.

-- 
 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.