Question & Answer
Question
How can we improve the performance of reports by using cached data when running a report in Cognos Analytics 11?
Answer
When you run a report, the query request is sent to the database and the result set is returned. After the initial report execution, you may decide to make changes to the report. Often, the report can be created without querying the database again. To take advantage of this, you should turn the query reuse feature on.
When query reuse is turned on and you run a report for the first time, the query is stored in the cache of your current session and reused the next time you run the report. The queries are kept in the cache for each user. The cache is cleared when the report consumer exits the Report Authoring tool and returns to the portal or when the report server times out the session.
Query reuse can be set on the model or on individual reports. To specify that all reports using a particular model should use cached data, enable the ‘Allow Usage of Local Cache’ governor on the model in Framework Manager and republish the model. By default, this setting affects all reports that use this model.
Query Reuse in Report Viewer or Cognos Viewer
If you want a report to use a different setting than the model, you can do this in the Report Authoring tool of Cognos Analytics 11. In the Properties section against a specific query, change the ‘Use Local Cache’ property. Set the property to ‘No’ if you want to always execute the query. Set the property to ‘Yes’ if you want to use cached results. If you want the report to use the same setting as the model, change the setting to ‘Default’.
Changing the ‘Use Local Cache’ property for one report will not affect other reports.
Deciding Whether to Use Query Reuse in Your Environment
Before deciding whether or not to turn query reuse on, you should consider the following:
If most report consumers run reports interactively but run them only once, you may not experience a high level of performance improvement by caching data. Note: Regardless of the query reuse settings, reports that are run in batch do not cache data.
The size of the cache may impact scalability. For example, if a report has a large result set, the cache will also be large. This should be taken into account when sizing and configuring your server environment.
Steps to enable/disable the cache in Cognos Analytics 11 Framework Manager:
1. Open up your model in Cognos Analytics 11 Framework Manager.
2. Click on ‘Project’ in the menu and select ‘Edit Governors…’. This will open the Governors Dialog.
3. Check the box beside ‘Allow usage of local cache’ to enable/disable the default use of local cache.
To enable/disable the cache in a specific report in Cognos Analytics 11:
1. Open the report in the Report Authoring tool.
2. Under the ‘Queries’ tab on the left-hand side, click on the query which you want to configure the cache for.
3. Click on the ‘Properties’ tab in the top-right and under ‘Use local cache’, change the setting to either ‘Yes’, ‘No’ or ‘(Default)’.
Related Information
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Document Information
Modified date:
15 June 2018
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