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From: Nathan Bossart <nathandbossart@gmail.com>
To: Nazir Bilal Yavuz <byavuz81@gmail.com>
Cc: Andrew Dunstan <andrew@dunslane.net>
Cc: Shinya Kato <shinya11.kato@gmail.com>
Cc: Manni Wood <manni.wood@enterprisedb.com>
Cc: KAZAR Ayoub <ma_kazar@esi.dz>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
Date: Mon, 24 Nov 2025 15:59:21 -0600
Message-ID: <aSTVOe6BIe5f1l3i@nathan> (raw)
In-Reply-To: <CAN55FZ0e_L_O2O5W4E39vap1rz=OJjVqT7w--7gYeHpHK0a2aQ@mail.gmail.com>
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On Thu, Nov 20, 2025 at 03:55:43PM +0300, Nazir Bilal Yavuz wrote:
> On Thu, 20 Nov 2025 at 00:01, Nathan Bossart <nathandbossart@gmail.com> wrote:
>> +            /* Load a chunk of data into a vector register */
>> +            vector8_load(&chunk, (const uint8 *) &copy_input_buf[input_buf_ptr]);
>>
>> In other places, processing 2 or 4 vectors of data at a time has proven
>> faster.  Have you tried that here?
> 
> Sorry, I could not find the related code piece. I only saw the
> vector8_load() inside of hex_decode_safe() function and its comment
> says:
> 
> /*
>  * We must process 2 vectors at a time since the output will be half the
>  * length of the input.
>  */
> 
> But this does not mention any speedup from using 2 vectors at a time.
> Could you please show the related code?

See pg_lfind32().

-- 
nathan

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  Cc: nathandbossart@gmail.com, byavuz81@gmail.com, andrew@dunslane.net, shinya11.kato@gmail.com, manni.wood@enterprisedb.com, ma_kazar@esi.dz
  Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
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