Re: Proving IS NOT NULL inference for ScalarArrayOpExpr's

From: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
To: James Coleman <jtc331(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Proving IS NOT NULL inference for ScalarArrayOpExpr's
Date: 2019-01-22 10:26:50
Message-ID: 201901221026.zsvxo427vlmh@alvherre.pgsql
Views: Raw Message | Whole Thread | Download mbox
Thread:
Lists: pgsql-hackers

Hello, I gave this patch a very quick scan. I didn't check the actual
logic behind it.

This comment seems wrong:

+ * However weak implication fails: e.g., "NULL IS NOT NULL" is false, but
+ * "NULL = ANY(ARRAY[NULL])" is NULL, so non-falsity does not imply non-falsity.

"non-falsity does not imply non-falsity"? I suppose one of those
negations should be different ...

I think the name clause_proved_for_null_test() is a bit weird, being in
the past tense. I'd maybe change "proved" to "proves".

s/exppresions/expresions/ in the test files.

--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Fabien COELHO 2019-01-22 10:31:46 Re: [PATCH] pgbench tap tests fail if the path contains a perl special character
Previous Message Raúl Marín Rodríguez 2019-01-22 10:20:50 Re: [PATCH] pgbench tap tests fail if the path contains a perl special character