Re: Make COPY format extendable: Extract COPY TO format implementations

Hi,

In <b1c8c9fa-06c5-4b60-a2b3-d2b4bedbbde9(at)enterprisedb(dot)com>
"Re: Make COPY format extendable: Extract COPY TO format implementations" on Tue, 30 Jul 2024 11:51:37 +0200,
Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> wrote:

> I decided to do the benchmark for individual parts of the patch series.
> The attached PDF shows results for master (label 0000) and the 0001-0005
> patches, along with relative performance difference between the patches.
> The color scale is the same as before - red = bad, green = good.
>
> There are pretty clear differences between the patches and "direction"
> of the COPY. I'm sure it does depend on the hardware - I tried running
> this on rpi5 (with 32-bits), and it looks very different. There might be
> a similar behavior difference between Intel and Ryzen, but my point is
> that when looking for regressions, looking at these "per patch" charts
> can be very useful (as it reduces the scope of changes that might have
> caused the regression).

Thanks.
The numbers on your environment shows that there are
performance problems in the following cases in the v18 patch
set:

1. 0001 + TO
2. 0005 + TO

There are +-~3% differences in FROM cases. They may be noise.
+~6% differences in TO cases may not be noise.

I also tried another benchmark with the v19 (not v18) patch
set with "Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz" not "AMD
Ryzen 9 3900X 12-Core Processor".

The attached PDF visualized my numbers like your PDF but red
= bad, green = good. -30 (blue) means 70% (faster) and 30
(red) means 130% (slower).

0001 + TO is a bit slower like your numbers. Other TO cases
are a bit faster.
0002 + FROM is very slower. Other FROM cases are slower with
less records but a bit faster with many records.

I'll re-run it with "AMD Ryzen 9 3900X 12-Core Processor".

FYI: I've created a repository to push benchmark scripts:
https://gitlab.com/ktou/pg-bench

Thanks,
--
kou