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

Sergei Kornilov <sk@zsrv.org>

From: Sergei Kornilov <sk@zsrv.org>

To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Stephen Frost <sfrost@snowman.net>

Cc: Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>

Date: 2018-04-06T07:28:00Z

Lists: pgsql-hackers

Hello, Peter!
I agree my patch seems as strange workaround. And better will be SET NOT NULL NOT VALID feature. But this change is very complicated for me
For now my patch is small, simple and provides way for users.

regards, Sergei

06.04.2018, 06:29, "Peter Eisentraut" <peter.eisentraut@2ndquadrant.com>:
> On 11/29/17 10:52, Sergei Kornilov wrote:
>>  My target problem of adding NOT NULL to big relation without long downtime can be done with ADD CONSTRAINT NOT VALID, VALIDATE it in second transaction, then SET NOT NULL by my patch and drop unneeded constraint.
>
> It seems to me that this is a workaround for not properly cataloguing
> NOT NULL constraints. If we fixed that, you could do SET NOT NULL NOT
> VALID and go from there. Maybe we should look again into fixing that.
> That would solve so many problems.
>
> --
> Peter Eisentraut http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

Avoid using INFO elevel for what are fundamentally debug messages.
- db438318997b 13.0 landed
- 121e3ceed6d9 12.0 landed
Revert setting client_min_messages to 'debug1' in new tests.
- 5655565c077c 12.0 landed
Allow ALTER TABLE .. SET NOT NULL to skip provably unnecessary scans.
- bbb96c3704c0 12.0 landed
Improve predtest.c's internal docs, and enhance its functionality a bit.
- 5748f3a0aa7c 11.0 cited