Comments on: MySQL: what read_buffer_size value is optimal ?

By: A Brief Introduction to MySQL Performance Tuning | Gary Pendergast

A Brief Introduction to MySQL Performance Tuning | Gary Pendergast — Tue, 01 Sep 2009 12:58:19 +0000

[...] – Another one that shouldn’t be set too large. Peter Zaitsev did some testing a while back showing that increasing sort_buffer_size can in fact reduce the speed of the [...]

By: Project 2061 Techlog » Best Practices for Setting MySQL Server Runtime Parameters

Wed, 08 Oct 2008 21:00:03 +0000

[...] MySQL Performance Blog: MySQL: what read_buffer_size value is optimal? [...]

By: peter

peter — Wed, 24 Sep 2008 20:04:55 +0000

Thanks Apachez,

I guess this is how rounding works.

By: Apachez

Apachez — Wed, 24 Sep 2008 19:51:47 +0000

I have now filed the above as bug http://bugs.mysql.com/39634

By: Apachez

Apachez — Sun, 21 Sep 2008 11:18:33 +0000

Is it just me or how do you properly set the buffers to 128 kbyte?

I put this in my my.cnf:

key_buffer_size = 256M
sort_buffer_size = 128K
read_buffer_size = 128K
read_rnd_buffer_size = 128K
join_buffer_size = 128K
myisam_sort_buffer_size = 128K

and restarted the mysql process, the result when running “SHOW VARIABLES LIKE ‘%buffer%’;” is the following (only including the rows regarding to the my.cnf):

key_buffer_size 268435456
sort_buffer_size 131064
read_buffer_size 126976
read_rnd_buffer_size 126976
join_buffer_size 126976
myisam_sort_buffer_size 131072

The key_buff shows the proper “268435456″ which is 256*1024*1024, but what about the rest? Shouldnt they all show 131072 which is 128*1024 or am I missing something here?

By: Son Nguyen

Son Nguyen — Wed, 10 Sep 2008 21:40:58 +0000

Wow, I’m glad I found this benchmark and not wasting investing into more memory (I’m just begin to see swap with one of our servers)

By: Bigger isn’t always better for MySQL at Jason Clawson

Bigger isn’t always better for MySQL at Jason Clawson — Tue, 20 May 2008 00:40:16 +0000

[...] looks like the guys over at the MySQL Performance Blog came to the same conclusion I did: Leave read_buffer_size to its default value. Changing it [...]

By: 记录/分享/…… » Blog Archive » A Few Common Performance Mistakes

记录/分享/…… » Blog Archive » A Few Common Performance Mistakes — Fri, 07 Mar 2008 01:33:43 +0000

[...] http://www.mysqlperformanceblog.com/2007/09/17/mysql-what-read_buffer_size-value-is-optimal/ http://www.mysqlperformanceblog.com/2006/06/06/are-larger-buffers-always-better/ [...]

By: Big DBA Head! - Database Brain Power! » A Few Common Performance Mistakes

Big DBA Head! - Database Brain Power! » A Few Common Performance Mistakes — Thu, 06 Mar 2008 16:19:35 +0000

[...] http://www.mysqlperformanceblog.com/2007/09/17/mysql-what-read_buffer_size-value-is-optimal/ [...]

By: Data Management Today by Craig Mullins

Data Management Today by Craig Mullins — Fri, 21 Sep 2007 16:01:14 +0000

Log Buffer #63: a Carnival of the Vanities for DBAs…

Welcome to the 63rd edition of Log Buffer, the weekly review of database blogs. For those of you reading…