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From: Tom Lane <tgl@sss.pgh.pa.us>
To: James Cloos <cloos@jhcloos.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: using possibly null timestamptz columns
Date: Thu, 29 Sep 2016 09:05:48 -0400
Message-ID: <5086.1475154348@sss.pgh.pa.us> (raw)
In-Reply-To: <m3a8eqx4rx.fsf@carbon.jhcloos.org>
References: <m3a8eqx4rx.fsf@carbon.jhcloos.org>
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James Cloos <cloos@jhcloos.com> writes:
> Given a table with a pair of timestamptz columns (lets call them s and e)
> which are typically null, is there a better way to write this where clause
> snippet:

>     where ( s is null or s <= now() ) and ( e is null or e >= now() )

You could try constructing a GIST or SPGIST index on the ranges
tstzrange(s, e), where you'd have to do something to convert null
endpoints to infinities, and then probing with WHERE rangeexpr @> now().

I'm not really sure how well this would perform, but certainly you're
dead in the water as far as doing anything useful with regular btree
indexes.

			regards, tom lane


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