Effects of Performance Tuning on Availability

Performance tuning is one of the most beneficial functions that a database administrator can perform. Fortunately, these efforts not only improve performance, but may also have some impact on improving availability.

As has been previously cited, when machine resources are utilized to their absolute maximum, instabilities have a greater likelihood of surfacing and resulting in instance crashes and "blue screens". Effective performance tuning tends to reduce the resource demands considerably, thus reducing process errors resulting from over-extended resources. For instance, tuning an application with indexes will typically allow queries associated with the application to execute much faster. In addition to faster query execution, tuning via indexing tends to improve buffer cache hit percentage and, especially in DSS-type applications, sort area hit percentages. Since tuned queries execute faster, it should quite obvious that fewer machine-level resources are required to execute the queries. If a reasonable level of application tuning is performed on all applications in an instance, then the instance can utilize machine-level resources much more efficiently. In turn, keeping the machine-level resources from over-extending contributes to a more stable installation.

Please see the section regarding performance tuning and analysis for more detailed information.