From: | Denis Perchine <dyp(at)perchine(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | lockhart(at)fourpalms(dot)org, pgsql-general(at)postgresql(dot)org |
Subject: | Re: Index on timestamp field, and now() |
Date: | 2002-02-12 15:38:50 |
Message-ID: | 20020212121530.32F681FE84@mx.webmailstation.com |
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Lists: | pgsql-general |
On Tuesday 12 February 2002 21:34, Tom Lane wrote:
> Denis Perchine <dyp(at)perchine(dot)com> writes:
> > webmailstation=> explain select * from queue where send_date > timestamp
> > 'now';
> >
> > But I use a comparison with now() + '20 years'::interval, not with
> > now()...
>
> That's not the example you quoted. More to the point, if you write it
> that way then it isn't a constant, at least not in 7.2's limited
> understanding of what constant values are. You could work around that
> with a custom function marked isCachable; see the archives.
Oups. Sorry my mistake. But 7.2's limited understanding is enough to do
constant propagation as far as I can see. :-)))
webmailstation=> explain select * from queue where send_date > timestamp
'now' + '20 years'::interval;
NOTICE: QUERY PLAN:
Index Scan using queue_senddate_key on queue (cost=0.00..30.55 rows=8
width=192)
EXPLAIN
Thanks for the hint.
--
Denis
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