Horton

Re: define pg_structiszero(addr, s, r)

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Ranier Vilela <ranier.vf@gmail.com>, Michael Paquier <michael@paquier.xyz>, Peter Smith <smithpb2250@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers@lists.postgresql.org
Date: 2024-11-05T05:49:22Z
Lists: pgsql-hackers 
Hi,

On Tue, Nov 05, 2024 at 05:08:41PM +1300, David Rowley wrote:
> I was happy enough with my patch with Bertrand's comments.  I'm not
> sure why unsigned chars are better than chars. It doesn't seem to have
> any effect on the compiled code.
> 

I think that unsigned chars is better than char for byte level memory
operations (no sign extension issues).

Though I agree that using char in this function is not an issue as p is only
compared with 0. This is more a matter of taste here.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

Commits

  1. Use pg_memory_is_all_zeros() in PageIsVerifiedExtended()

  2. Optimize pg_memory_is_all_zeros() in memutils.h

  3. Remove use of pg_memory_is_all_zeros() in bufpage.c

  4. Add pg_memory_is_all_zeros() in memutils.h