The database statistics function of System i Navigator provides the ability to manage statistical information for a table. This statistical information and other factors can then be used by the query optimizer to determine the best access plan for a query.
To be of value, this statistical information must be accurate and complete. Since the query optimizer bases its choice of access plan on the statistical information found in the table, it is important that this information be current.
On many platforms, statistics collection is a manual process that is the responsibility of the database administrator. With i5/OS, the database statistics collection process is handled automatically, and it is rarely necessary for the statistics to be manually updated, even though it is possible to manage statistics manually.
If you collect the statistics manually and you explicitly set the statistics to be maintained manually, not allowing the system to perform automatic updates, or if you want to speed up the automatic update process, then the statistics should be updated when:
You can perform the following statistics related tasks:
View details or error data of a statistics request
View and change the background collection status
Refresh the statistics requests lists