Re: Revisiting extract(epoch from timestamp)

Excerpts from Tom Lane's message of lun abr 09 15:38:21 -0300 2012:
>
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> >> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >>> If somebody needs it I'd probably be in favor of doing it. I'm not
> >>> sure I'd do it on spec.
>
> > It would be useful to have a simple function to use with timestamp in
> > constraint exclusion without having to use contorted expressions ...
> > An immutable extract_epoch(timestamptz) would fit the bill.
>
> What exactly would you do with it there that you couldn't do more easily
> and clearly with plain timestamp comparisons? I'm willing to be
> convinced, but I want to see a case where it really is the best way.

You mean, having the constraint declaration rotate the timestamptz
column to timestamp and then extract the epoch from that? If you go
that route, then the queries that wish to take advantage of constraint
exclusion would have to do likewise, which becomes ugly rather quickly.

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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