One day like many, on a JBoss AS Forum:
I am running the Acme project using JBoss 5.1.0. My requirement is to allow 1000 concurrent users to access the application. But when I try to access the application with 250 users, the server slows down and finally throws an exception "Could not establish a connection with the database. Does anyone have an idea please help me to solve my problem."
In the beginning, performance was not a concern for software. Early programming languages like C or Cobol were doing a decent job of developing applications and the end user was just discovering the wonders of information technology that would allow him to save a lot of time.
Today we are all aware of the rapidly changing business environment in which we work and live and the impact it has on business and information technology. We recognize that an organization needs to deliver faster services to a larger set of people and companies, and that downtime or poor responses of those services will have a significant impact on the business.
To survive and thrive in such an environment, organizations must consider it an imperative task for their businesses to deliver applications faster than their competitors or they will risk losing potential revenue and reputation among customers.
So tuning an application in today's market is firstly a necessity for survival, but, there are even more subtle reasons, like using your system resources more efficiently. For example, if you manage to meet your system requirements with fewer fixed costs (let's say by using eight CPU machine instead of a 16 one) you are actually using your resources more efficiently and thus saving money. As an additional benefit you can also reduce some variable costs like the price of software licenses, which are usually calculated on the amount of CPUs used.
On the basis of these premises, it's time to reconsider the role of performance tuning in your software development cycle, and that's what this book aims to do.