Re: Index on timestamp field, and now() - Mailing list pgsql-general

From Denis Perchine
Subject Re: Index on timestamp field, and now()
Date
Msg-id 20020212121530.32F681FE84@mx.webmailstation.com
Whole thread Raw
In response to Re: Index on timestamp field, and now()  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Index on timestamp field, and now()  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Tuesday 12 February 2002 21:34, Tom Lane wrote:
> Denis Perchine <dyp@perchine.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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