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help / color / mirror / Atom feedFrom: Nathan Bossart <nathandbossart@gmail.com>
To: Nazir Bilal Yavuz <byavuz81@gmail.com>
Cc: Manni Wood <manni.wood@enterprisedb.com>
Cc: KAZAR Ayoub <ma_kazar@esi.dz>
Cc: Neil Conway <neil.conway@gmail.com>
Cc: Andrew Dunstan <andrew@dunslane.net>
Cc: Shinya Kato <shinya11.kato@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
Date: Wed, 11 Mar 2026 15:42:38 -0500
Message-ID: <abHTvkeIK37hj9oS@nathan> (raw)
In-Reply-To: <CAN55FZ0yfETy4UEA5rOJ9S06JSOtiWF8TW_+yi3yjVAcrLqKLA@mail.gmail.com>
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<CAN55FZ2DNaKCK3Kf_kHizb2pAbQvULeDYtzaiz97B_xz7YbrkQ@mail.gmail.com>
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<CAN55FZ3gdK8dGrEo0M6KFW97OaF8TUbjO_dFoxQKi63davE-jA@mail.gmail.com>
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On Wed, Mar 11, 2026 at 10:22:18PM +0300, Nazir Bilal Yavuz wrote:
> Here is v14 which is v13-0001 + v13-0002.
Thanks! It's getting close.
> + /*
> + * Temporary variables are used here instead of passing the actual
> + * variables (especially input_buf_ptr) directly to the helper. Taking
> + * the address of a local variable might force the compiler to
> + * allocate it on the stack rather than in a register. Because
> + * input_buf_ptr is used heavily in the hot scalar path below, keeping
> + * it in a register is important for performance.
> + */
> + int temp_input_buf_ptr;
> + bool temp_hit_eof = hit_eof;
A few notes:
* Does using a temporary variable for hit_eof actually make a difference?
AFAICT that's only updated when loading more data.
* Does inlining the function produce the same results?
* Also, I'm curious what the usual benchmarks look like with and without
this hack for the latest patch.
--
nathan
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Cc: nathandbossart@gmail.com, byavuz81@gmail.com, manni.wood@enterprisedb.com, ma_kazar@esi.dz, neil.conway@gmail.com, andrew@dunslane.net, shinya11.kato@gmail.com
Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
In-Reply-To: <abHTvkeIK37hj9oS@nathan>
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