Re: empty view, replace view, column type change?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Rod Taylor <pg(at)rbt(dot)ca>, Markus Bertheau <twanger(at)bluetwanger(dot)de>, PgSQL - SQL <pgsql-sql(at)postgresql(dot)org>
Subject: Re: empty view, replace view, column type change?
Date: 2005-06-24 04:32:15
Message-ID: 200506240432.j5O4WF026888@candle.pha.pa.us
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Tom Lane wrote:
> > If you SELECT 'abc'::varchar(6)::varchar, the end type is varchar(6).
>
> Yeah, this is exactly what's happening --- if you look at gram.y,
> LOCALTIMESTAMP is expanded to "'now'::text::timestamp(6)". I am
> unconvinced that the (6) is a very good idea though. The code says
>
> /* SQL99 mandates a default precision of 6 for timestamp.
> * Also, that is about as precise as we will get since
> * we are using a microsecond time interface.
> * - thomas 2001-12-07
> */
> d->typmod = 6;
>
> but it doesn't seem to me to follow from what the spec says that we need
> to explicitly cast the result of now() to six places. As long as it's
> coming from gettimeofday it can't have more than 6 places anyway, and so
> we might as well save the extra coercion step. (The parser *will* tack
> on a separate coercion function call when presented with this parse
> tree.)
>
> In short, I'm inclined to remove the above-quoted lines, and similarly
> for CURRENT_TIME, CURRENT_TIMESTAMP, and LOCALTIME. Thoughts?

Agreed. That "6" bothered me too when I was cleaning up the timestamp
code a while back.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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