I'm running Ubuntu server 12.04 on a computer at home, granted it's a netbook so there's not a lot of performance to squeeze out of it, but I'm still wondering about the memory usage I'm seeing from /usr/sbin/mysqld.
When I run htop and sort by memory usage, I get 16 processes on top, all of them running from the mysqluser and pointing at the command /usr/sbin/mysqld. Combined, these processes use about 55% of my total memory. Is this normal? The load average looks pretty low otherwise, and the CPUs and swap don't seem to be used much.