Horton

Re: Cost of XLogInsert CRC calculations

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Mark Cave-Ayland" <m.cave-ayland@webbased.co.uk>
Cc: "'Manfred Koizar'" <mkoi-pg@aon.at>, "'Greg Stark'" <gsstark@mit.edu>, "'Bruce Momjian'" <pgman@candle.pha.pa.us>, pgsql-hackers@postgresql.org
Date: 2005-05-27T14:00:27Z
Lists: pgsql-hackers 
"Mark Cave-Ayland" <m.cave-ayland@webbased.co.uk> writes:
> Opt	32     32a    32b    2x32   64     64a      64b
> --------------------------------------------------------
> O1	4.91   4.86   5.43   6.00   11.4   11.39    11.39
> O2	4.96   4.94   4.69   5.18   15.86  18.75    24.73
> O3	4.82   4.83   4.64   5.18   15.14  13.77    14.73

Not sure I believe these numbers.  Shouldn't 2x32 be about twice as slow
as just one 32-bit CRC?

			regards, tom lane