Horton

Re: Proving IS NOT NULL inference for ScalarArrayOpExpr's

Alvaro Herrera <alvherre@2ndquadrant.com>

View thread View on postgr.es
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: James Coleman <jtc331@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, David Rowley <david.rowley@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-22T10:26:50Z
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

Commits

  1. Teach optimizer's predtest.c more things about ScalarArrayOpExpr.