Re: Numeric x^y for negative x

From: Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>
To: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Numeric x^y for negative x
Date: 2021-07-07 17:36:56
Message-ID: CAEZATCWAiXp7ocU3AMV6Pyvgv3O8x4-UBY+d=w+pziXXegdyOA@mail.gmail.com
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On Thu, 1 Jul 2021 at 14:17, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
>
> On Tue, 29 Jun 2021 at 12:08, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
> >
> > Numeric x^y is supported for x < 0 if y is an integer, but this
> > currently fails if y is outside the range of an int32
>
> I've been doing some more testing of this, and I spotted another
> problem with numeric_power().
>
> [loss of precision and overflow errors]
>
> I think we should attempt to avoid all such overflow errors,
> that are actually underflows, and return zero instead.
>

Finally getting back to this ... attached is an updated patch that now
includes a fix for the loss-of-precision bug and the overflow errors.
I don't think it's really worth trying to split these up, since
they're all somewhat interrelated.

Regards,
Dean

Attachment Content-Type Size
numeric-power-fixes.patch text/x-patch 7.0 KB

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