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Cognos performance can be impacted by multiple factors, therefore you may need to implement more than one best-practice in order to optimize your report performance.

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If your report is interactive and has multiple pages.

If your report has multiple pages for your customer to click through you can break your report into separate reports that can be accessed via hyperlinks or drill-thrus.

If your report has if then else statements.

Replace your if-then-else statements with case-when-else-end statements, Cognos is able to process case statements faster.

If your report has a prompt page.

Queries that populate the prompt page can be sources from views that contain less data. Cognos will be able to return results faster if it is working with a smaller view.

If your report has custom data items / custom calculations.

There are two places that custom calculations can be processed: on the Cognos server or the AH Hana server. Processing custom calculations on the Cognos server requires that all the data be brought to the Cognos server and thus takes more time. You can force Cognos to process custom calculations on the Hana server by using Hana preferred syntex and using calculations before joining queries in Cognos. See Cognos Training for examples.

Custom calculations are assigned auto aggregation. This means Cognos will take it’s best guess as to how to add up the custom calculation, which takes additional processing power and may result in an unwanted outcome. Best practice is to always set the aggregation on custom data items.

If your report is based on a Detail view.

Detail views have the most rows of data related to a topic. Not all reports require all of those rows. If you find your report only needs summary data then repoint your report at a summary view or request a new summary view.