Apache::AuthenDBI NOTICE message

[George Sanderson]

It turns out that I am learning about DBI and Apache::DBI.
So far, using Apache::AuthenDBI, I get an error_log message:

NOTICE:  Unrecognized variable client_encoding

Every time the DBI ping is called.
I have not been able to tack down the origin of this message.
Any ideas or suggestions?