Specifying data elements for local caching
If you enabled local caching, you can configure specific data elements to be cached locally. This includes data that is frequently updated during common operations, such as selecting values, sorting, and filtering.
Not every dashboard feature allows data to be cached – and some data should not be cached. However, remote and locally cached data work together to provide consistent results, while reducing the server load.
About this task
To tune your local caching, you can create separate data caches, then apply different caching rules to each one. By enabling and disabling different data caches, you can discover the combination of enabled data caches that works best for you.
When local caching is enabled, Cognos Analytics will leverage the feature where possible. In use cases where local caching is not possible, queries will be remote, but may still leverage query service caching.
The size that is stated in the error message is the amount of browser memory that all caches consume and not the system memory of your client machine. You can add filters to reduce the overall size of your local caches and avoid reaching this size limit by clicking the Filter icon that is beside any categorical column.
Limitations of this feature include the following:
- Crosstab visualizations
- Top or bottom filters
- Navigation paths
- Model Filters and Parameters
- Tables with Ranks applied
- Cognos Explorations/Stories
- Calculations of type
Aggregate then Calculate
- Tables with Average summaries
- Count distinct aggregation type
- Widgets and visualizations that are set to automatically refresh
Click the Properties icon.
If you don't see the Properties icon, click the Switch to edit icon.
- For the entire dashboard or story, ensure that nothing else has focus by clicking the background, away from any visualization or object.
- Expand Advanced, and then next to Configure local cache, click Edit.
- In the Configure data caching pane, click
Auto create data caches.
One or more objects, named Data cache n appear. The number of queries, columns, and filters appears under its name.Troubleshooting : If the Auto create data caches process does not complete, you may need to update certain HTTP Server configuration files. For information about resolving this issue, see 'Auto create data caches' progress starts but does not complete configuring data caches (https://www.ibm.com/support/pages/node/6997029).
- To see details of the columns currently designated for caching, click a
Data cache n link.
The column names are listed.Note: When data caches are auto-created, all available columns are initially listed for caching.
- To remove a column from the list, click the trash can icon next to the column name.
- To restore a column to the list, click the Add icon , select a column from the list, and then click Add, Tip: If nothing happens after you click the Add icon , there are no more columns available to add.
- To see which widgets currently have columns designated for caching – and
will therefore perform faster – click the Widgets tab.
The widget names are listed.Note: When data caches are auto-created, all available widgets with cached columns are initially listed.
- To remove a widget from the list, click the Columns tab and remove any columns associated with the widget.
- To restore a widget to the list, click the Add icon , select a widget with columns not currently in this data cache, and then click
Add. Tip: If nothing happens after you click the Add icon , there are no more widgets with uncached columns available to add.
- To create another data cache, in the Configure data caching pane, click the Action icon , click Add data cache, and then configure another combination of cached columns and widgets.
- After you've determined the combination of data caches that provides the best
overall performance, you can enable them and then disable the rest by choosing one or both of these
Tip: If you created your dashboard in Cognos Analytics 12.0, the Auto-generate on save option is enabled by default. When this option is enabled, the local cache is generated each time you save your dashboard.
- In the Configure data caching pane, click the Action icon , and then click Enable all or Disable all.
- Select the toggle icon next to one or more data caches to enable or disable the caching rules that you configured for that data cache.
If your dashboard was upgraded to version 12.0, the Auto-generate on save option is disabled by default. However, you can enable it if you wish.