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 2E117E25-084A-4B8D-9C59-39F5FD4363DE@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  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
Hi,

Le 26 juin 09 à 05:20, Jeremy Kerr a écrit :
>> Unfortunately, the cases with lots of padding spaces are probably
>> much less probable than the cases with fewer.  It would be unpleasant
>> for example if this patch resulted in a severe performance
>> degradation for a "canonical" example of char(n) being used properly,
>> such as char(2) for US state abbreviations.
>
> Yep, makes sense. The other consideration is stock-ticker symbols, I
> assume they may also be stored in CHAR(small n) columns.


Could this optimisation only kicks in when n is "big enough"?
I'm don't know if this part of the code knows the typmod...

Regards,
--
dim

pgsql-hackers by date:

Previous
From: KaiGai Kohei
Date:
Subject: [PATCH] [v8.5] Security checks on largeobjects
Next
From: Scara Maccai
Date:
Subject: Query progress indication - an implementation