Support Article
High memory utilization with summary type report definition
SA-8031
Summary
Developer created a summary type report definition with a large number of group by columns, and observes very high memory utilization during the report execution.
Error Messages
Not Applicable.
Steps to Reproduce
Run a summary type report definition having large number of group by columns, which retrieves thousands of records (large dataset).
Root Cause
The root cause of this problem is software use or operation error.
A nested page structure will be generated for the groupings, by the report definition.
Report definition (summary type) with high numbers of "group bys" for the columns generate a large amount of virtual memory overhead.
This is exacerbated in cases where the order of the groupings is not "most general" to "most specific", as more nodes are generated in the nested page structure.
Resolution
Pega recommends user to review the groupings and eliminate any unnecessary ones, and reorder the remaining ones if possible to reduce the overhead.
For example, pyID is not a good candidate for a group by (or) a first group by, as it will always give a group of 1.
Published January 31, 2016 - Updated October 8, 2020
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