Data caching in dashboards

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Data caching in dashboards

In continued efforts to ensure Dashboards perform at their best we are introducing the ability to control data caching at the overall dashboard level.

You will find Data cache under the properties of the dashboard. The default value is Automatic which picks up the corresponding setting from the data source a widget is connected with. In version 11.0.11 the Automatic setting only applies if you are using a Framework Manager package but it is expected that future versions of Cognos Analytics will support caching properties within data modules. The corresponding setting in Framework Manager is a governor called Allow usage of local cache.

The dashboard data cache property also has options to turn it On (cache is used whenever possible) or Off (never cache data). These apply to live connections to data servers within a package or data module but are not applicable to data sets or uploaded files.

This data cache contains results from SQL queries to data servers that retrieved the data presented in dashboard widgets. In processing a dashboard widget, the system determines whether the widget is a candidate for reusing cached data. If so, the system will check whether the results for a compatible SQL statement have been cached for the same data server connection. If so, that cached data will be reused.

Results that are cached from one user’s dashboard can be reused for a different user’s dashboard only if both users have the same data security profiles. No need to worry about users seeing data that they should not.

This cached data is retained in a Cognos Analytics server’s memory for as long as the original connection to the underlying data server remains open. These connections have a default idle timeout of 300 seconds (5 minutes) which can be modified in the Administration console.

When the dashboard widget property Refresh Automatically is turned on, data caching won’t occur for that widget no matter what.