# mysql (mis?)configuration: "thread_concurrency"



## cbrace (Apr 25, 2011)

Hi all,

I have installed Joomla v1.6 on my FreeBSD server. It seems _really_ slow, even though the server hardware should be adequate: AMD Athlon II X2 250 with 2GB RAM. 

Googling this, I discover a few hits in which people mention that some MySQL tuning improves Joomla 1.6 performance, such as this one on a Joomla forum.

Further searches reveal that the FreeBSD port does not automatically include a default my.cnf for MySQL. So I copied one of the sample config files in /usr/local/share/mysql to /usr/local/etc/my.cnf and restarted mysql.

However, mysql wouldn't restart. Looking in the error log /var/db/mysql/venus.err, I found this:


```
110425 10:42:50 [ERROR] /usr/local/libexec/mysqld: unknown variable 'thread_concurrency=8'
110425 10:42:50 [ERROR] Aborting
```

I commented this out of my.cnf and then mysql started properly.

I am curious whether anyone knows why this apparently *invalid* parameter would be included in the sample configuration files.

I am running MySQL version 5.5.4, which I installed via a package.


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## vivek (Apr 25, 2011)

I think thread_concurrency only works on OpenSolaris / Solaris UNIX. So you will not see this on Linux or FreeBSD or other UNIX like oses.


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## quintessence (Apr 28, 2011)

vivek said:
			
		

> I think thread_concurrency only works on OpenSolaris / Solaris UNIX. So you will not see this on Linux or FreeBSD or other UNIX like oses.



Hello,
not true. 

On 5.1 it works, now I'm installing 5.5.x from yesterday ports to test and will edit the post.

http://bugs.mysql.com/bug.php?id=55001

On 5.5.11 mysql doesn't return this error, you can search for the fix for your version in the URL above.


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