Bursting Explained - Part I

I have been asked by so many users what happens behind the scenes when Cognos bursts a report? Why do burst reports take longer to complete? etc. And I have explained about master-detail relationships and its impact on Burst reports in an earlier post. In this post and the next couple of posts I am going to try and cover the various burst scenarios and how many SQLs Cognos fires against the backend in each scenario.

Bursting is made up of 3 components:

The Burst Query or Report Query: The report query that needs to be burst. The report could be a single query report or multi-query report. In case of a multi-query report, each data container in the report needs to have a master-detail relationship set up with the burst group query.



The Burst Group Query: The query that decides the burst group. For each record in the burst group query the report is sliced.

Example: A report needs to be burst for each Sales Regions. In this case the burst group would be the Sales Region. The report is sliced for each Sales Region record generated by the burst group query.

The Burst Recipient Query: The query that provides the recipient information.



Scenario 1: A single Burst Query, Burst Group Query, Burst Recipient Query.

In this case the list in the report, the burst group and the burst recipient information is fed by a single query.

Example: Burst a Sales report based on Sales Regions to be made available to users through Cognos Connection Directory.

Query 1 Data Items: Year, Sales Region, Sales, Recipient.

Recipient - CAMID('Everyone')

In the above Example, since burst group, burst recipient and list report are sourced from a single query, Cognos runs this query once, retrieves the entire data set and then slices the report output for the various sales regions. Hence only 1 query is fired by Cognos in this case.



Links to Part II, Part III