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Function documentation SQL Optimizer Statistics Locate the document in the library structure

Use

The database system determines a series of statistical information when it is running, such as the number of table entries, the sizes of the tables and indexes and the value distribution of indexes and columns. The database system stores these statistics in the database catalog.

The SQL Optimizer requires these statistics to determine the best strategy for processing complex SQL statements. You therefore have to update these statistics at regular intervals.

Recommendation

We recommend that you update the statistics once a week. Always update the statistics whenever the size relationships or values in the database instance change considerably.

Activities

To update the SQL Optimizer statistics use the Database Manager or, in SAP systems, the CCMS. See

·        Database Manager GUI, Update Statistics Information

·        Database Manager CLI,

¡        Updating the Optimizer Statistics

¡        Automatically Updating the Optimizer Statistics

·        Database Administration in CCMS, Structure linkScheduling the Update of the SQL Optimizer Statistics

See also:

Concepts of the Database System, Performance

 

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