The DB2 UDB database monitor offers some functions for finding storage management problems in the database.

Using these functions, you can trace tablespaces of the database that need more disk space and find out whether tables or indexes are fragmented and require reorganization.

To access these functions, select Tools ® Administration ® Monitoring ® Performance ® Database ® Tables/Indexes or call Transaction DB02.

Storage management problems generally develop so slowly that they are detected in time and can be eliminated. However, such problems can also turn up very quickly during the data transfer phase of the R/3 System implementation if you transfer mass data from an old system into a new one.

A tablespace consists of one or more tablespace containers in which the database objects are stored. A container can be a directory, a file or a raw device. Each container can be put on a different disk. The database manager attempts to balance the load of the data across the containers of one tablespace. All containers will be used to store data. The number of pages written to a container before the next container is used is called the Extent Size.

Two different tablespace types can be used with a DB2 UDB database:

• the System Managed Space (SMS) tablespace type, where the operating system's file manager controls the storage space

• the Database Managed Space (DMS) tablespace type, where the database manager controls the storage space.

The DB2 UDB database monitor offers functions for examining the allocated and free storage space of the database.

The state overview screen, Database performance: tables and indexes, shows the total number of table spaces, the total allocated space and the freespace in the database. Furthermore, the amount of freespace of the fullest tablespace is shown (Minimum free/kB).