From: | Andrew Gould <andrewgould(at)yahoo(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Postgres Mailing List <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: requesting features in PostgreSQL |
Date: | 2002-04-26 16:49:29 |
Message-ID: | 20020426164929.8716.qmail@web13407.mail.yahoo.com |
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Thread: | |
Lists: | pgsql-general |
One request is certainly not sufficient for a new
standard feature. As I see more industries becoming
data savvy, however, I think it's time will come.
Until then....
Simple python scripts are the extent of my coding
experience. As I will be processing 2 to 6 million
records within one query, I guess I should learn some
C.
Once I untar PostgreSQL's source, where can I find the
code for avg()? Will it have it's own file?
Thanks,
Andrew
--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Andrew Gould <andrewgould(at)yahoo(dot)com> writes:
> > I need an aggregate function that calculates
> geometric
> > mean, and can be used in SQL statements the same
> as
> > any other aggregate function such as count(),
> sum()
> > and avg(). Rather than have a custom function,
> I'd
> > like to see it added as a standard PostgreSQL
> feature.
>
> One request does not strike me as sufficient reason
> to make it a
> standard feature. Extensibility is what Postgres is
> all about
> --- so go ahead and write your own.
>
> AFAICS this should take about ten minutes to
> prototype (two simple
> plpgsql or pltcl functions and a user-defined
> aggregate). If you intend
> to process very large volumes of data, it might be
> worth rewriting the
> transition function in C for speed. (You could
> steal the existing
> transition function for avg() as a model.)
>
> regards, tom lane
>
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