| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "D(dot) Duccini" <duccini(at)backpack(dot)com> |
| Cc: | Bruno Wolff III <bruno(at)wolff(dot)to>, pgsql-sql(at)postgresql(dot)org, Pgsql-novice <pgsql-novice(at)postgresql(dot)org> |
| Subject: | Re: date_trunc'd timestamp index possible? |
| Date: | 2004-10-01 21:17:28 |
| Message-ID: | 15053.1096665448@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-novice pgsql-sql |
"D. Duccini" <duccini(at)backpack(dot)com> writes:
> I think we found a way around it!
> CREATE OR REPLACE FUNCTION date_immutable( timestamptz ) RETURNS date AS
> 'SELECT date( $1 ) ;' LANGUAGE 'sql' IMMUTABLE ;
No, you just found a way to corrupt your index. Pretending that
date(timestamptz) is immutable does not make it so. The above
*will* break the first time someone uses the table with a different
timezone setting.
What you can do safely is date(footime AT TIME ZONE 'something'),
since this nails down the zone in which the date is interpreted.
regards, tom lane
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