Re: Greatest Common Divisor

On Fri, Jan 3, 2020 at 10:23 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Now, those functions were just exposing libc functionality, so there
> wasn't a lot of code to write. There might be a good argument that
> gcd isn't useful enough to justify the amount of code we'd have to
> add (especially if we allow it to scope-creep into needing to deal
> with "numeric" calculations). But I'm not on board with just
> dismissing it as uninteresting.

Yeah. There's always the question with things like this as to whether
we ought to push certain things into contrib modules that are not
installed by default to avoid bloating the set of things built into
the core server. But it's hard to know where to draw the line. There's
no objective answer to the question of whether gcd() or sinh() is more
useful to have in core; each is more useful to people who need that
one but not the other, and trying to guess whether more or fewer
people need gcd() than sinh() seems like a fool's errand. Perhaps in
retrospect we would be better off having a 'math' extension where a
lot of this stuff lives, and people who want that extension can
install it and others need not bother. But, to try to create that now
and move things there would break upgrades for an exceedingly marginal
benefit. I don't really like the namespace pollution that comes with
accepting feature requests like this, but it's hard to argue that it's
a serious show-stopper or that the cure is any less bad than the
disease. And I'm sure that I'd be much more likely to use gcd() or
lcm() in a query than tanh()...

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company