Horton

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

Sergei Kornilov <sk@zsrv.org>

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From: Sergei Kornilov <sk@zsrv.org>
To: Ildar Musin <i.musin@postgrespro.ru>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Stephen Frost <sfrost@snowman.net>, Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-03-09T14:51:25Z
Lists: pgsql-hackers 
Hello all!
Summarizing, how i must update tests?
We want test real skip of verify phase or only result correctness?

I can verify what i do not break alter table by tests in v4 of my patch. But here is no check code path. So my feature may be broken in future without test fail. alter table will be correct regardless this feature.
Or i must test code path too? I understood Tom and will remove INFO ereport from patch anyway. But currently i have no idea how check code path. As mentioned earlier using debug ereport is uncomfortable too. Here is no suitable event trigger to track what exactly happens with table. Adding new one for test purposes seems overkill.

regards, Sergei

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.