The setup is Hibernate 3.1 / MySQL 4 / Spring. MySQL Monitor shows about 100 queries/second, and everything works just fine. However, I've noticed that the network traffic has increased tremendously, following a very weird pattern. While my application server is receiving about 1.5MB/s of traffic from the database, it is sending in excess of 10MB/s of traffice to the database.

This is weird because there is very little writing going on for the dataset, and I'd say 99% of the time data is being read rather than written. To find out what's going on, I run tcpdump and sniff around. And much to my surprise, I've found out that most of the outgoing traffice form the application server isn't SQL queries at all, but more like a lot of environmental queries and setting going on, things like setting AUTO_COMMIT=on, setting the character set and so on and so forth.

I am wondering if I have set anything wrong.