Official Support and Optimization for Master-Detail Relationships with Data Modules

Currently, master-detail optimization is not officially supported for data modules. While a workaround exists, we require this feature to be officially supported to ensure a reliable and performant analytics experience for our customers.

Business Justification:
Data modules are the future of Cognos, and we aim to build all new applications based on the Trino datasource using data modules instead of Framework Manager packages. However, the lack of official support and performance optimization for master-detail relationships in data modules presents significant challenges:

1. Performance Disparity:

   1. Master-detail optimization with data modules is significantly slower compared to Framework Manager packages.

   2. The performance of master-detail relationships must be optimized to ensure parity between data modules and packages.

2. Crosstab Compatibility:

   1. Master-detail optimization does not currently work with crosstabs, which is a critical feature for our customers.

3. Trino Datasource Challenges:

   1. Master-detail relationships with Trino are not optimized, leading to poor performance. Trino introduces significant overhead to queries, and Cognos sends a large number of detail queries sequentially to the datasource, making report execution much slower compared to databases like DB2.

   2. Concurrent query execution for master-detail relationships is not supported, further exacerbating performance issues.

Proposed Enhancements:

• Officially support master-detail optimization for data modules.

• Optimize master-detail performance in data modules to match the performance of Framework Manager packages or make it even better.

• Enable master-detail optimization for crosstabs.

• Enabling concurrent query execution for use cases where master-detail optimization is not enabled.

Impact on Customers:
Our customers expect a performance-optimized analytics experience. The current limitations result in:

• Significantly slower report execution for master-detail relationships with Trino compared to traditional databases.

• Inability to use crosstabs with master-detail optimization, which is a critical requirement for many use cases.

• A lack of support for master-detail optimization in data modules, despite data modules being the recommended approach for new applications.

Conclusion:
To meet customer expectations and align with the strategic direction of Cognos, it is essential to provide official support and performance optimization for master-detail relationships in data modules. Addressing these issues will enhance the user experience, improve performance, and ensure that data modules can fully replace Framework Manager packages for modern analytics solutions.