IBM Tivoli Monitoring, Version 6.3

Database maintenance

A regularly scheduled maintenance plan is essential for maintaining peak performance of your system.

Regular maintenance, which involves running the REORG, RUNSTATS, and REBIND facilities in that order on the database tables, is a critical factor in the performance of a database environment. Implement at least a minimum weekly maintenance schedule.

REORG
After many INSERT, DELETE, and UPDATE changes to table data, often involving variable length columns activity, the logically sequential data might be on non-sequential physical data pages. The database manager must perform additional read operations to access data. You can use the REORG command to reorganize DB2 tables, eliminating fragmentation and reclaiming space.
RUNSTATS
The DB2 optimizer uses information and statistics in the DB2 catalog to determine optimal access to the database based on the provided query. Statistical information is collected for specific tables and indexes in the local database when you run the RUNSTATS utility.
REBIND
After running RUNSTATS on your database tables, you must rebind your applications to take advantage of those new statistics.
Dynamic SQL
Dynamic SQL statements are prepared and executed at run time. In dynamic SQL, the SQL statement is contained as a character string in a host variable and is not precompiled. Dynamic SQL statements and packages can be stored in one of the DB2 caches.
Static SQL
Static SQL statements are embedded within a program, and are prepared during the program preparation process before the program is executed. After preparation, a static SQL statement does not change, although values of host variables that the statement specifies can change. These static statements are stored in a DB2 object called a package.

Parent topic: Database design details

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