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Re: strange IS NULL behaviour

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Hannu Krosing <hannu@2ndquadrant.com>, Peter Eisentraut <peter_e@gmx.net>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2013-09-05T16:57:59Z
Lists: pgsql-hackers 
On Wed, Sep 4, 2013 at 9:26 PM, Bruce Momjian <bruce@momjian.us> wrote:
> On Tue, Sep  3, 2013 at 09:32:44PM -0400, Bruce Momjian wrote:
>> In this test, SELECT NULL (which internally would produce SELECT
>> ROW(NULL)), returns TRUE, while SELECT ROW(NULL) and further nesting
>> returns false.
>>
>> This has made me adjust my goal and change it so SELECT ROW(NULL) IS
>> NULL returns true, and any further nesting returns false.
>>
>> Attached is a patch which accomplishes this, and a documentation update.
>
> I have not heard any feedback on this patch, so I would like to apply it
> to give us a nested ROW/IS NULL API we can document.  It would have to
> be marked in the release notes as a backward incompatibility.

I don't have time to look at this in detail right now, but I think
that's considerably premature.  I'm not convinced that we understand
all of the problems in this area are yet, let alone the solutions.
And I notice that you haven't substantively responded to some of Tom's
concerns.

So -1 from me.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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