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To: Magnus Hagander <magnus@hagander.net>
cc: David Jarvis <thangalin@gmail.com>,
	Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>,
	pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: Analysis Function 
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Comments: In-reply-to Magnus Hagander <magnus@hagander.net>
	message dated "Sun, 13 Jun 2010 17:49:50 +0200"
Date: Sun, 13 Jun 2010 11:58:24 -0400
Message-ID: <14336.1276444704@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Magnus Hagander <magnus@hagander.net> writes:
> On Sun, Jun 13, 2010 at 17:42, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> ... (We presumably want
>> timezone to default to the system timezone setting, but I wonder how
>> we should make that work --- should an empty string be treated as
>> meaning that?)

> Umm. NULL could be made to mean that, or we could provicde two
> different versions - one that takes TZ and one that doesn't.

Using NULL like that seems a bit awkward: for one thing it'd mean the
function couldn't be STRICT, and also it'd be bizarre that only this
one argument could be null without leading to a null result.

And two separate functions isn't good either.  Basically, I think it's
important that there be a way to specify an explicit parameter value
that behaves identically to the default.

> And a third, construct_time(), no?

Yeah, maybe ... do you think there's any demand for it?

			regards, tom lane