Feedback-ID: i0fe9450f:Fastmail
Date: Wed, 24 Jan 2024 17:11:49 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Sutou Kouhei <kou@clear-code.com>
Cc: sawada.mshk@gmail.com, zhjwpku@gmail.com, andrew@dunslane.net,
	nathandbossart@gmail.com, pgsql-hackers@postgresql.org
Subject: Re: Make COPY format extendable: Extract COPY TO format
 implementations
Message-ID: <ZbDGReKwHGjnGiH-@paquier.xyz>
References: <20240111.102445.1008569098168542133.kou@clear-code.com>
 <20240112.144615.157925223373344229.kou@clear-code.com>
 <20240115.152702.2011620917962812379.kou@clear-code.com>
 <20240124.144936.67229716500876806.kou@clear-code.com>
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On Wed, Jan 24, 2024 at 02:49:36PM +0900, Sutou Kouhei wrote:
> For COPY TO:
>=20
> 0001: This adds CopyToRoutine and use it for text/csv/binary
> formats. No implementation change. This just move codes.

10M without this change:

    format,elapsed time (ms)
    text,1090.763
    csv,1136.103
    binary,1137.141

10M with this change:

    format,elapsed time (ms)
    text,1082.654
    csv,1196.991
    binary,1069.697

These numbers point out that binary is faster by 6%, csv is slower by
5%, while text stays around what looks like noise range.  That's not
negligible.  Are these numbers reproducible?  If they are, that could
be a problem for anybody doing bulk-loading of large data sets.  I am
not sure to understand where the improvement for binary comes from by
reading the patch, but perhaps perf would tell more for each format?
The loss with csv could be blamed on the extra manipulations of the
function pointers, likely.
--
Michael

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