Semi OT: MySQL memory probs...

[alex at crackpot.org]

Quoting Randy Melder <randymelder at gmail.com>:

> We've got an environment with ALL innodb tables and been forced to use
> OS X servers. They are total memory and CPU hogs. Just hoping there
> were some people that had some insight into OS X server, why it abuses
> virtual memory and how best to deploy mysql on it.
>
> Me thinks that the MySQL binary has memory leaks... but that's just a guess.

If you're using all innodb tables, use a tiny key buffer.  Currently,  
you're allocating 2GB of RAM in a buffer that will probably never be  
used.  Temporary tables will still be created as MyISAM, but I'm  
thinking that they can't benefit much from a key cache anyway (unless  
you have long-running threads that create temp tables and keep them  
around for  along time).

Way back in 2005 there was a pretty interesting report/benchmark which  
basically boiled down to "MySQL on OSX is horribly broken".  The  
testers lay the blame more with the OS (and it's threading  
implementation) than with MySQL.  MySQL has gone through many releases  
since then, and Apple hardware has switched from PowerPC to Intel  
chips, and several OSX updates have been released.  I'm not sure if  
this is still relevant, but it's an interesting read.

"Mac OS X is incredibly slow, between 2 and 5(!) times slower, in  
creating new threads, as it doesn't use kernel threads, and has to go  
through extra layers (wrappers). No need to continue our search: the  
G5 might not be the fastest integer CPU on earth - its database  
performance is completely crippled by an asthmatic operating system  
that needs up to 5 times more time to handle and create threads."

http://www.anandtech.com/mac/showdoc.aspx?i=2436&p=8

alex