Determining actions to resolve exceptions
After you identify the possible causes of the exceptions, you can determine the best approach for tuning the areas.
Before you begin
About this task
In this task, you will determine the best approach for resolving exceptional states of a DEDB area. Key decision indicators are the database record profile of the area, the distribution of randomizing synonyms, and their effects on the root I/Os and database record I/Os.
By completing this task, you will be able to determine whether reorganizing the free space in the area will resolve the exceptional state or whether elaborate tuning tasks, such as tuning database definitions or randomizer, are required.
Procedure
The approach for database tuning varies depending on whether the record profile and the
number of database records have changed or not.
- If the record profile and the number of database records have been relatively unchanged
- If exceptions that are related to free space fragmentation, free space usage,
or overflow usage were reported earlier than you expected, consider reviewing the current criteria
for reorganization or the current reorganization schedule, and refine them if necessary. If the
exceptions are related to free space fragmentation, free space usage, or overflow usage, and if the
number of database records in the area has been relatively unchanged, consider reorganizing free
space, which does not require changes to the DBD definitions.Free space reorganization is especially recommended if a free space fragmentation exception was reported or if the Freespace Analysis report indicates either or both of the following conditions:
- Free space elements are fragmented, and the number of free space fragments that are smaller than the segment size has increased
- The percentage of CIs that have enough total free space but that have many references to other sections of the database has increased
- If the record profile or the number of database records have significantly changed
- Determine if tuning of the DBD definitions or the randomizer is required.