Difference between connection pooling and simple connection

Question

Anybody please tell me what is the Difference between connection pooling and simple connection and also where we define connection pooling and how.
Thanks
Please reply soon
amitindia

Answer 1

Creating and closing connection to the database is a relatively slow process. Equally connections use database resources so you can't just open as many as you want.
A connection pool maintains a number of open connections throughout the lifetime of the application. Instead of opening and closing the connections your application just "borrows" them from the pool when they're needed.
If the pool runs out of connections it will usually create new ones as needed until you reach some predefined upper limit.
A good connection pool will also manage connections which have failed for any reason, and report code which fails to return connections to the pool (ie connection leaks).
The number of connections created at startup is referred to as the "low water mark" and the maximum number that the pool will allow to be opened at any given time is the "high water mark". If no connections are available client code will generally block until one is released.
If by "defined" you mean where can you get a working implementation then your database or application server vendor is likely to provide one. Also the Apache Jakarta Commons includes [url http://jakarta.apache.org/commons/dbcp/]an implementation which you can use with any JDBC driver.
Dave.