Re: Semi OT: MySQL memory probs...

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Author: alex@crackpot.org
Date:  
To: plug-discuss
Subject: Re: Semi OT: MySQL memory probs...
Quoting Randy Melder <>:

> 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
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