This is probably the easiest way to access a MySQL database from Java. Everything seemed to be fine until i recently ran a few days long test of the daemon application on one of our test servers. It did not like me in the long run, i am still not sure why and whether it really was a Conenctor/J problem or not.

In any case, the problem i have faced was CPU usage suddenly started raising to about 50% (in a period of one day) and it wasnt a spike – it was a steady raise. When i checked the log file there were no warnings except one i got a at the end of the day: MySQL connection link failure.

Now one may wonder – how is this related to MySQL Connector. Well, it seems to me that it was due to Statement cancellation timer lockup that it started causing problems. Right now i have modified the code of the application to cancel all statemnts explicitly as well as some forced Garbage Collection, just to make sure that nothing unwanted slips by. The new test has been deployed to the servers and we are about to see if it has any effect.

Another note about Java (not really MySQL related):
It seems to be smart using “-server” option when starting a VM if the application is supposed to run for a very long time. The performance optimization is huge: we are talking about almost 2x performance optimization compared to “-client” VM (default).

There are some bad things about it – but there are even some good ones, and in all honesty — that makes it up for me.

Now you might wonder – what’s so good about that slow, old language? Well, it is widely spread and there are tons of different open-source classes available which makes your life easier. Then there is type-hinting in Java makes it really hard to mess up with wrong data types comming in. And it IS suited for enterprise development.

I have been working with Java for quite some time now, and thou i still dont like it for pure web-app development (probably because i still didnt get a hang of Templating in JSP) it is damn nice and i like it more and more.