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help / color / mirror / Atom feedFrom: Nathan Bossart <[email protected]>
To: Nazir Bilal Yavuz <[email protected]>
Cc: Manni Wood <[email protected]>
Cc: KAZAR Ayoub <[email protected]>
Cc: Neil Conway <[email protected]>
Cc: Andrew Dunstan <[email protected]>
Cc: Shinya Kato <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
Date: Mon, 2 Mar 2026 13:55:05 -0600
Message-ID: <aaXrGSyq4u2d9qEC@nathan> (raw)
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On Wed, Feb 25, 2026 at 05:24:27PM +0300, Nazir Bilal Yavuz wrote:
> If anyone has any suggestions/ideas, please let me know!
A couple of random ideas:
* Additional inlining for callers. I looked around a little bit and didn't
see any great candidates, so I don't have much faith in this, but maybe
you'll see something I don't.
* Disable SIMD if we are consistently getting small rows. That won't help
your "wide & CSV 1/3" case in all likelihood, but perhaps it'll help with
the regression for narrow rows described elsewhere.
* Surround the variable initializations with "if (simd_enabled)".
Presumably compilers are smart enough to remove those in the non-SIMD paths
already, but it could be worth a try.
* Add simd_enabled function parameter to CopyReadLine(),
NextCopyFromRawFieldsInternal(), and CopyFromTextLikeOneRow(), and do the
bool literal trick in CopyFrom{Text,CSV}OneRow(). That could encourage the
compiler to do some additional optimizations to reduce branching.
--
nathan
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Subject: Re: Speed up COPY FROM text/CSV parsing using SIMD
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