Automatic maintenance
The database manager provides automatic maintenance capabilities for performing database backups, keeping statistics current, and reorganizing tables and indexes as necessary. Performing maintenance activities on your databases is essential in ensuring that they are optimized for performance and recoverability.
- Backups. When you back up a database, the database manager takes a copy of the data in the database and stores it on a different medium in case of failure or damage to the original. Automatic database backups help to ensure that your database is backed up properly and regularly so that you don't have to worry about when to back up or know the syntax of the BACKUP command.
- Data defragmentation (table or index reorganization). This maintenance activity can increase the efficiency with which the database manager accesses your tables. Automatic reorganization manages an offline table and index reorganization so that you don't need to worry about when and how to reorganize your data.
- Data access optimization (statistics collection). The database manager updates the system catalog statistics on the data in a table, the data in indexes, or the data in both a table and its indexes. The optimizer uses these statistics to determine which path to use to access the data. Automatic statistics collection attempts to improve the performance of the database by maintaining up-to-date table statistics. The goal is to allow the optimizer to choose an access plan based on accurate statistics.
It can be time-consuming to determine whether and when to run maintenance activities, but automatic maintenance removes the burden from you. You can manage the enablement of the automatic maintenance features simply and flexibly by using the automatic maintenance database configuration parameters. By setting the automatic maintenance database configuration parameters, you can specify your maintenance objectives The database manager uses these objectives to determine whether the maintenance activities need to be done and runs only the required ones during the next available maintenance window (a time period that you define).
In IBM® Data Studio Version 3.1 or later, you can use the task assistant for configuring automatic maintenance. Task assistants can guide you through the process of setting options, reviewing the automatically generated commands to perform the task, and running these commands. For more details, see Administering databases with task assistants.