Maintenance of Good Performance

Performance is affected in some way by all system users: the database server administrator, the database administrator, the application designers, and the client application users.

The database server administrator usually coordinates the activities of all users to ensure that system performance meets overall expectations. For example, the operating-system administrator might need to reconfigure the operating system to increase the amount of shared memory. Bringing down the operating system to install the new configuration requires bringing the database server down. The database server administrator must schedule this downtime and notify all affected users when the system will be unavailable.

The database server administrator should:

• Be aware of all performance-related activities that occur.
• Educate users about the importance of performance, how performance-related activities affect them, and how they can assist in achieving and maintaining optimal performance.

The database administrator should pay attention to:

• How tables and queries affect the overall performance of the database server
• The placement of tables and fragments
• How the distribution of data across disks affects performance

Application developers should:

• Carefully design applications to use the concurrency and sorting facilities that the database server provides, rather than attempt to implement similar facilities in the application.
• Keep the scope and duration of locks to the minimum to avoid contention for database resources.
• Include routines within applications that, when temporarily enabled at runtime, allow the database server administrator to monitor response times and transaction throughput.

Database users should:

• Pay attention to performance and report problems to the database server administrator promptly.
• Be courteous when they schedule large, decision-support queries and request as few resources as possible to get the work done.