[ale] mysql and high load levels

[Jeff Hubbs]

Jenn -

If it were me - and please understand that I have very, very little
experience with MySQL - but I'd try going back to a 2.2 kernel first. 
You're right in that the size of the tables is trivial, but I know that
the 2.4 kernels do memory management differently.  It seemed to me that
2.4 kernels on high-RAM (>=256MB) machines acted kind of aggressive with
RAM and with swap - at least the kernels that have been coming with RH
7.1 and Mandrake 8.0.  

Do you have a drive fight going on?  Are your indices and tables on
separate drives/arrays or, better yet, different controllers as well? 
What about your swap?  Is it similarly split out?  

- Jeff

P.S.  If you hit on a solution, i'd be intersted to know what it is.

djinn wrote:
> 
> Does anyone out there have experience running mysql in a production
> environment with medium sized tables?  We're talking 80 - 150MB data
> files...
> 
> Mysql's official word is that the tables can be as big as the OS will
> let them but we're having some really hideous problems recently with
> load levels going absolutely thru the roof in seconds...I watch as my
> normal 1 - 3 load level jumps to 20 in 10 seconds...then to 40..then to
> 80...and I have to kill mysql and wait for everything to close and calm
> back down before I can restart it.  Needless to say, this is NOT good.
> 
> I have been successfully running mysql in a production environment for 2
> years now, on lesser boxen than I'm running on.  There's no problem with
> CPU or RAM (tho when the load level gets so high, the CPU utilization
> goes thru the roof too).
> 
> Here are my theories, if someone could help me troubleshoot...I'm in the
> 5th day of this.  I've searched the web and turned up nothing...but I
> know I'm just not asking the right questions.
> 
> 1) Using a new version of mysql...3.23.41.  Installed 3.23.38 and had
> the same problems.  I know they're trying to introduce all sorts of
> "real database" type stuff...could that be a problem?
> 
> 2) I have a handful of heavily hit, large tables.  The load levels seem
> to go insane when two of the large tables are hit about the same time.
> But not consistantly.  I'm taking steps to reduce the size of the
> tables, but the largest one is only about 150Mb and I'm having trouble
> believing that MySQL could be balking at that.
> 
> 3) Using kernel 2.4.7...which is my first time out with the 2.4 kernel.
> Is there possibly something that I'm missing in my config, should I have
> compiled in to use the new mysql (maybe a dumb question, but i'm rnning
> out of thoughts)??
> 
> Any suggestions?
> 
> Thanks
> jenn
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