Automatic cache clearing

By default, the caches used in the dynamic query mode are cleared every 24 hours to avoid producing reports based on potentially old data. The actual time at which each cache is cleared depends on when the cache was created.

You can override the default interval for automatic cache clearing or disable it entirely for each type of data source. Examples of types of data sources are SAP BW, Oracle Essbase, and OLAP over relational. You can also override or disable the interval for specific data sources, catalogs, and cubes.

To override the default interval, edit the configuration file c10_location\configuration\xqe.securecache.config.xml. This file contains comments that describe each parameter, their possible values, and their interpretation. Then restart the IBM® Cognos® service. Changes to this file affect only the cache for instances of the query service that are running on the server where the configuration file resides. In a distributed environment, you must change the file on each server.

Important: If you create scheduled jobs to clear the caches for data sources, catalogs, and cubes, disable automatic cache clearing for their corresponding data sets. For more information about creating scheduled jobs to clear the cache, see Create and schedule query service administration tasks.

For more information about how the cache works, see the IBM Cognos 10 Dynamic Query Cookbook in the Cognos Proven Practices section of the IBM website (http://www.ibm.com/developerworks/data/library/cognos/cognosprovenpractices.html).