MySQL 5.6 Release Notes
The --log-warnings
option or
log_warnings
system variable
controls warning logging to the error log. The default value is
enabled (1). To disable warning logging, set
--log-warnings
or
log_warnings
to 0. If the value
is greater than 1, aborted connections are written to the error
log, and access-denied errors for new connection attempts are
written. See Section B.3.2.10, “Communication Errors and Aborted Connections”.