9.7

The netstat command (available on Linux and on Windows) shows the active network connections on a computer. Explain how this command can be used to find out if a particular web page is not closing connections that it opened, or if connection pooling is used, not returing connections to the connection pool. You should account for the fact that with connection pooling, the connection may not get closed immediately.

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The tester should run netstat to find all connections open to the machine/socket used by the database. (If the application server is separate from the database server, the command may be executed at either of the machines). Then the web page being tested should be accessed repeatedly (this can be automated by using tools such as JMeter to generate page accesses). The number of connections to the database would go from 0 to some value (depending on the number of connections retained in the pool), but after some time the number of connections should stop increasing. If the number keeps increasing, the code underlying the web page is clearly not closing connections or returning the connection to the pool.