This option clears the in-memory cache that Mondrian builds; caching is used to improve query performance. Flushing the cache is not usually necessary except when underlying data in the database changes. For example, after running an ETL process, the cache is out of date; it may not match the data in the database.

Such data changes are not reflected in OLAP views until the application server is restarted or until the cache is flushed.

To flush the cache, click Manage > Server Settings, click OLAP Settings, and click Flush OLAP Cache near the top of the page.

The OLAP cache is also automatically flushed when an existing Mondrian connection or one of its components (such as the schema or data source) is changed in the repository.

For more information on caching, see the Jaspersoft OLAP Ultimate Guide and the JasperReports Server Administrator Guide.