Re: [PATCH] backend: compare word-at-a-time in bcTruelen - Mailing list pgsql-hackers

From Dimitri Fontaine
Subject Re: [PATCH] backend: compare word-at-a-time in bcTruelen
Date
Msg-id 80F3A08D-54AC-4E6B-AAF9-D64F14FD324C@hi-media.com
Whole thread Raw
In response to Re: [PATCH] backend: compare word-at-a-time in bcTruelen  (Jeremy Kerr <jk@ozlabs.org>)
Responses Re: [PATCH] backend: compare word-at-a-time in bcTruelen  (tomas@tuxteam.de)
List pgsql-hackers
Le 26 juin 09 à 14:47, Jeremy Kerr a écrit :
> For the new function to be faster, we need to know that there are more
> than 6 (on average, depending on alignment) trailing spaces.

It's becoming somewhat tricky, but maybe the test to do for the
optimisation to get used is n >= threshold && str[n-6] == 0x20, àla
Boyer/Moore?

I call it tricky because you could have a space here which isn't
followed by spaces, but still, if it's not a space here, you're saying
we should not even try the optimisation.

--
dim

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