MySQL hangs server completely

[Michael Ross]

On Wed, 22 May 2013 15:52:45 +0200, Alejandro Imass <aimass at yabarana.com>  
wrote:

> Hi,
>
> We've been having this problem with a customer for a while and it
> seems that some funky query makes MySQL use 100% of CPU. Nevertheless,
> even though you can see in top that it's only 1 CPU in 100% (out of 8)
> the server eventually becomes useless and stops responding completely.
>
> So my question is, how does a user process hang the whole server? What
> system resources could MySQL be draining to make the server stop
> responding completely?
>

In laymans terms - can't do better - MySQL racing itself to obtain a (  
table | memory | file ) lock?

I know I can death-stall the MySQL server at a customer's site if I give  
it a big enough query ( like, DROPping a table, recreating it and pushing  
backup data inside ) while cron's hourly backup-dump is running on the  
database. Just the MySQL server, the machine itself hasn't stalled yet -  
but I'm sitting at the console while doing this, so I don't know what  
would eventually happen if I'd let it sit for a while.


Regards,

Michael