Join performance for heterogeneous data sources
To improve performance when querying heterogeneous data sources in IBM® Cognos® Analytics, you can specify join filters in data modules, Framework Manager, or Reporting.
By using this feature, you can push predicates (the filter values) from the table on the 1 side of the query into the filter expression of the SQL of the table on the n side of the query. For information about setting the join filters, see the related component documentation.
For information about setting the join filters in the different Cognos Analytics components, see the following documentation:
- Data modules: Join optimization
- Framework Manager: Optimizing joins by applying filters
- Reporting: Create a Join Relationship
There are some additional considerations when working with multiple data sources. For more in-depth information on this subject, and to learn how to improve performance, see this article (www.ibm.com/support/pages/node/6258353).