High CPU usage for mysqld_safe

Set up a combo FE/BE on a fresh install of Mythbuntu 9.04 on an Acer X1200 (2300+ Sempron X2 / 3 GB RAM / GeForce 8200 / HDMI).

Everything works fine, minus very high CPU usage for the 'mysqld_safe' process. I've ran the 'optimize_mythdb.pl' script, as well as running MySQL repairs. Even when MythTV backend and Apache are stopped, the process pegs one of my cores at 100%.

Output from syslog at start of process, with no further data following for five minutes following start:

*****
Apr 30 15:14:14 mythtv mysqld_safe[32560]: started
Apr 30 15:14:14 mythtv mysqld[32563]: 090430 15:14:14 InnoDB: Started; log sequence number 0 112623
Apr 30 15:14:14 mythtv mysqld[32563]: 090430 15:14:14 [Note] /usr/sbin/mysqld: ready for connections.
Apr 30 15:14:14 mythtv mysqld[32563]: Version: '5.0.75-0ubuntu10' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32601]: Upgrading MySQL tables if necessary.
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32607]: Looking for 'mysql' as: /usr/bin/mysql
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32607]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32607]: This installation of MySQL is already upgraded to 5.0.75, use --force if you still need to run mysql_upgrade
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32612]: Checking for insecure root accounts.
Apr 30 15:14:15 mythtv /etc/mysql/debian-start[32616]: Triggering myisam-recover for all MyISAM tables
*****

Process info:

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 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 2730 root 20 0 1872 496 468 R 100 0.0 1240:18 mysqld_safe
*****

Again, this is with MythTV backend/frontend and Apache (for MythWeb) all stopped.

I'm more than happy to do any troubleshooting/testing as necessary.