Using mySQL 5.0.51 on Solaris .
At intermittent times it looks like MySQL is getting 'stuck' . The disk usage on the server spikes to 98% busy from reads. I used dtrace (specifically DTrace toolkit - iosnoop) to track down what processes was using all the reads. Mysql was calling tablename.TDM hundreds of times per second. There was no more than average load on the webserver that could account for this. There were no cronjobs running, and no other utilities like mysqldump or anything. It is a master / slave replication setup.
As a jury-rigged fix, I altered the mysql table from 'tablename' to 'tablename2' and then back to 'tablename'
This fixed the problem temporarily, and "unsticks" mysql. The disk usage goes back down and dtrace is no longer showing hundreds of reads to 'tablename.TDM' / second.
A couple ideas I had are:
1. MySQL version bug 2. Infinite loop somewhere in my application (which i'm not sure how likely this is) 3. ??
Has anybody seen this before or have any insight?