Re: Speed up COPY FROM text/CSV parsing using SIMD

Hi,

On Tue, 8 Sept 2026 at 18:25, Nathan Bossart <nathandbossart(at)gmail(dot)com> wrote:
>
> On Tue, Sep 08, 2026 at 01:11:00PM +0300, Nazir Bilal Yavuz wrote:
> > Here is an attempt to solve this problem. I ran Manni's script and saw
> > a 1-2% slowdown on TEXT-wide inputs. It is still faster compared to
> > the version without the SIMD patch; the slowdown is relative to the
> > current master branch (which includes the SIMD patch).
>
> Thanks for reporting. Fable 5.1 suggests moving the check to
> CopyLoadInputBuf() to avoid this small regression, which makes sense to me.
> I've attached a new patch that does that. This is definitely a bit of
> hack, and I'm assuming we'll need to revisit this if we want to re-attempt
> more sophisticated heuristics for when to use the SIMD path. But IMHO this
> is self-contained enough to be reasonable for v19.

Thanks for v2; I agree that it is better. I confirm that it solves the
problem and doesn't cause the 1-2% regression I mentioned.

--
Regards,
Nazir Bilal Yavuz
Microsoft