Re: Improve compression speeds in pg_lzcompress.c - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Improve compression speeds in pg_lzcompress.c
Date
Msg-id 17407.1357593576@sss.pgh.pa.us
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In response to Re: Improve compression speeds in pg_lzcompress.c  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Improve compression speeds in pg_lzcompress.c
Re: Improve compression speeds in pg_lzcompress.c
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Jan 7, 2013 at 11:16 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Why would that be a good tradeoff to make?  Larger stored values require
>> more I/O, which is likely to swamp any CPU savings in the compression
>> step.  Not to mention that a value once written may be read many times,
>> so the extra I/O cost could be multiplied many times over later on.

> I agree with this analysis, but I note that the test results show it
> actually improving things along both parameters.

Hm ... one of us is reading those results backwards, then.
        regards, tom lane



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