Random Connection Issues - Error Log Lockups?

[Sam Kimmel]

Over the past week we've had a couple times when our IIS web server has been randomly and intermittently unable to communicate with the MySQL database server. They are VMs on the same physical box, so it shouldn't be a networking thing. There are no hops when doing a tracert.

The error being reported in our ASP.net logs is that the sites are unable to connect to MySQL. So I went to the MySQL error log to see if anything was going on there.

What I found is that we are getting thousands of these warnings in our error log:

"Client failed to provide its character set. 'utf8' will be used as client character set"

It appears that this may happening for every MySQL query. The log grows 2-3MB per hour.

1) Is it possible this Warning logging is reaching critical mass during high traffic periods and is essentially tying up the server due to read/write locks?

2) Why is the warning happening?

3) How do I stop it from continuing?

We ported our databases from MySQL 4 using mysqldump. These errors did not exist in the old version of the DB.