Java JDBC efficiency: How long should a connection be maintained?

Question

I\'m still working on the same problem mention here. It seems to work fine especially after creating an AbstractModel class shown below:

public abstract class Ab         


        

Answer 1

Your code should never depend on the fact, that your application is currently the only client to the database or that you have only 30 users. So you should handle database connections like files, sockets and all other kinds of scarce resources that you may run ouf of.

Thus you should always clean up after yourself. No matter what you do. Open connection, do your stuff (one or SQL statements) and close connection. Always!

In your code you create your connection and save it into a static variable - this connection will last as long as your AbstractModel class lives, probably forever - this is bad. As with all similar cases put you code inside try/finally to make sure the connection gets always closed.

I have seen application servers running ouf of connections because of web applications not closing connections. Or because they closed at logout and somebody said "we will never have more then that much users at the same time" but it just scaled a little to high.

Now as you have your code running and closing the connections properly add connection pooling, like zaske said. This will remedy the performance problem of opening/closing database connection, which truely is costly. On the logical layer (your application) you doesn't want to know when to open/close physical connection, the db layer (db pool) will handle it for you.

Then you can even go and set up a single connection for your whole session model, which is also supported by DBCP - this is no danger, since you can reconfigure the pool afterwards if you need without touching your client code.