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From: Nazir Bilal Yavuz <byavuz81@gmail.com>
Date: Thu, 26 Feb 2026 15:19:32 +0300
Message-ID: <CAN55FZ1inW-w-oqDwU32bLpC05XWQMY=SEMOtim74BNRekSjHQ@mail.gmail.com>
Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Manni Wood <manni.wood@enterprisedb.com>, KAZAR Ayoub <ma_kazar@esi.dz>, 
	Neil Conway <neil.conway@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, 
	Shinya Kato <shinya11.kato@gmail.com>, 
	PostgreSQL-development <pgsql-hackers@postgresql.org>
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Hi,

On Wed, 25 Feb 2026 at 17:24, Nazir Bilal Yavuz <byavuz81@gmail.com> wrote:
>
> I agree with you. However, unfortunately, I see regression on master +
> v10 compared to REL_18_3 (62d6c7d3df6).
>
> Thank you Kazar and Manni for benchmarks in [1] and [2]!

Kazar and Manni, if possible could you please share the build commands
you use? I see regressions for an inlining patch (dc592a4155) too when
I build postgres with -O2.

My build commands are:

-O2: meson setup buildtype=debugoptimized ...

-O3: meson setup buildtype=release ...

This is a wide benchmark only, old master means b2ff2a0b529 without
0001 inlining patch (dc592a4155):

+--------------------------+---------------+---------------+
|                          |      Text     |      CSV      |
+--------------------------+-------+-------+-------+-------+
|            -O2           |  None |  1/3  |  None |  1/3  |
+--------------------------+-------+-------+-------+-------+
|        Old Master        | 10440 | 11000 | 11940 | 13600 |
+--------------------------+-------+-------+-------+-------+
|     Old Master + 0001    | 10140 | 10800 | 11600 | 14300 |
+--------------------------+-------+-------+-------+-------+
| Old Master + 0001 + 0002 |  9000 | 11000 |  8850 | 15300 |
+--------------------------+-------+-------+-------+-------+
|                          |       |       |       |       |
+--------------------------+-------+-------+-------+-------+
|                          |      Text     |       |  CSV  |
+--------------------------+-------+-------+-------+-------+
|            -O3           |  None |  1/3  |  None |  1/3  |
+--------------------------+-------+-------+-------+-------+
|        Old Master        | 10440 | 11200 | 12200 | 14390 |
+--------------------------+-------+-------+-------+-------+
|     Old Master + 0001    | 10000 | 10700 | 11540 | 13960 |
+--------------------------+-------+-------+-------+-------+
| Old Master + 0001 + 0002 |  8880 | 10900 |  8900 | 15100 |
+--------------------------+-------+-------+-------+-------+

This result shows that when we compare v18 and v18 + SIMD (0001 +
0002), there is only regression for the CSV 1/3 case. The regression
is %12.5 for the -O2 and %5 for the -O3.

--
Regards,
Nazir Bilal Yavuz
Microsoft