Horton

Re: Cost of XLogInsert CRC calculations

Bruce Momjian <pgman@candle.pha.pa.us>

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From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Manfred Koizar <mkoi-pg@aon.at>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Mark Cave-Ayland <m.cave-ayland@webbased.co.uk>, pgsql-hackers@postgresql.org
Date: 2005-05-17T22:29:54Z
Lists: pgsql-hackers 
Manfred Koizar wrote:
> On Mon, 16 May 2005 12:35:35 -0400, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >Anyone want to try it with non-gcc compilers?
> 
> MS VC++ 6.0 with various predefined optimizer settings
> 
>                                 2x32        64
> Default (without any /O)     0.828125   0.906250
> MinSize (contains /O1)       0.468750   0.593750
> MaxSpeed (contains /O2)      0.312500   0.640625
> 
> Not that it really matters -- but at least this looks like another hint
> that letting the compiler emulate 64 bit operations on non 64 bit
> hardware is suboptimal.

I don't understand why we are testing 64-bit CRC when I thought we
agreed that 32-bit was good enough for our purposes.

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