"MySQL has a wonderful facility for capturing slow queries
called the slow query log. However if yours is not enabled when
trouble occurs, and restarting the database is not an option,
you'll need another solution. This is where a tcpdump can come in
handy. It can be used to watch a network interface and display the
packets and traffic. What Is A Tcpdump?
"Tcpdump is a Linux command for watching a network interface,
and displaying traffic that moves across it.
"On my Mac, the airport network interface (en1) is my main
connection to the internet. You may well want to use eth0 there.
So, I can do some packet sniffing with tcpdump as follows:"