The following table illustrates some of the monitoring statistics that may be used and what adjustments to (or tuning of) the database environment may result.

Changes in	May require tuning of ...
	Database Structure	Access Method Used	Hardware or Software Configuration	Processing Priority	Disk Storage Allocation
Terminal and line traffic		X	X	X	X
Response times (application performance)	X	X	X	X	X
Access totals by user and descriptor	X	X			X
Database size	X	X	X		X
Database growth rate	X	X	X		X

When any alteration is made to a production database, great care must be taken to ensure a continued high level of reliability and integrity. Whatever the change, the DBA must make sure that the decision is the right one and that it is properly and accurately implemented. He should retain absolute control over the tuning process and ensure that it follows the formal acceptance procedures.

The DBA must be very careful not to over-react to changes in the items listed in the table. A sudden change in line traffic, response times, etc., may only be a temporary affair. It is far better to wait for a while to see whether this is a permanent trend or a temporary disturbance to the normal way of operating. Another way of viewing the table is that the tuning required may be necessary when a new project will cause a significant change in terminal and line traffic, response times, etc. The DBA can then act in advance to minimize these effects before the new application system is implemented.