Re: Speed up COPY FROM text/CSV parsing using SIMD - Mailing list pgsql-hackers

On Tue, Jan 13, 2026 at 06:20:27PM -0600, Manni Wood wrote:
> On Tue, Jan 13, 2026 at 1:12 PM Mark Wong <markwkm@gmail.com> wrote:
>
> > On Fri, Jan 09, 2026 at 05:21:45PM +0300, Nazir Bilal Yavuz wrote:
> > > Were you able to understand why Mark's benchmark results are different
> > > from ours?
> >
> > Not yet... I had some guesses, which is why I suggested the processor
> > pinning
> > and using a ramdisk.  But we haven't tried applying all of those to my
> > laptop,
> > which has 3 core types, or the POWER system, which may be interesting to
> > use a
> > ram disk on.
> >
> > I'm curious though, and admittedly haven't tried looking myself yet, about
> > how
> > the SIMD calls might look across different processor architectures.  We'll
> > try
> > to get that on the POWER system soon...
> >
> > Regards,
> > Mark
>
> Hello!
>
> Nazir, I'm glad you are finding the benchmarks useful. I have more! :-)
>
> All of these benchmarks are all-in-RAM, because I do think that is the best
> way of getting closest to the theoretical best and worst case scenarios.
>
> My laptop:
>
> master: (852558b9)
>
> text, no special: 14996
> text, 1/3 special: 17270
> csv, no special: 18274
> csv, 1/3 special: 23852
>
> v3
>
> text, no special: 11282 (24.7% speedup)
> text, 1/3 special: 15748 (8.8% speedup) <-- I don't believe this but it's
> what I got
> csv, no special: 11571 (36.6% speedup)
> csv, 1/3 special: 19934 (16.4% speedup) <-- I don't believe this but it's
> what I got
>
> v4.2
>
> text, no special: 11139 (25.7% speedup)
> text, 1/3 special: 18900 (9.4% regression)
> csv, no special: 11490 (37.1% speedup)
> csv, 1/3 special: 26134 (9.5% regression)
>
> An AWS EC2 t2.2xlarge instance
>
> master: (852558b9)
>
> text, no special: 20677
> text, 1/3 special: 22660
> csv, no special: 24534
> csv, 1/3 special: 30999
>
> v3
>
> text, no special: 17534 (15.2% speedup)
> text, 1/3 special: 22816 (0.6% regression)
> csv, no special: 17664 (28.0% speedup)
> csv, 1/3 special: 29338 (5.3% speedup) <-- I don't believe this but it's
> what I got
>
> v4.2
>
> text, no special: 17459 (15.5% speedup)
> text, 1/3 special: 25051 (10.5% regression)
> csv, no special: 17574 (28.3% speedup)
> csv, 1/3 special: 32092 (3.5% regression)
>
> An AWS EC2 t4g.2xlarge instance (using ARM processor; first test of ARM
> processor!)
>
> master: (852558b9)
>
> text, no special: 22081
> text, 1/3 special: 25100
> csv, no special: 27296
> csv, 1/3 special: 32344
>
> v3
>
> text, no special: 17724 (19.7% speedup)
> text, 1/3 special: 27606 (9.9% regression) <-- yikes! We would want to test
> this more
> csv, no special: 17597 (35.5% speedup)
> csv, 1/3 special: 32597 (0.8% regression)
>
> v4.2
>
> text, no special: 17674 (20% speedup)
> text, 1/3 special: 25773 (2.6% regression) <-- this regression is less than
> for the v3 patch? Atypical...
> csv, no special: 17651 (35.3% speedup)
> csv, 1/3 special: 34055 (5.3% regression)

I'm still lagging behind a little  I ran the v4.2 patches again applied to
71c11369 on the POWER system that I have access to, using Manni's copysimdperf
scripts to use a ramdisk and processor pinning.

text, no special: -2508 (30% speedup)
text, 1/3 special: -1753 (48% speedup)
csv, no special: 9264 (3% regression)
csv, 1/3 special: -4077 (0.3% speedup)