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Support Article

OutOfMemory exceptions causing production outage



The Pega application is intermittently experiencing Out-Of-Memory (OOM) exceptions. These do not occur every day, but rather happen a few times a week.

Error Messages

OutOfMemory: Java heap space

Steps to Reproduce

There is not a specific set of steps to reproduce. 

Root Cause

An issue in the custom application code or rules: The application was creating thread-level data pages on each interaction. Under certain circumstances, these thread-level data pages were of moderate size (2 - 5 MB), and because there were such a high number of them created for each user on each thread, the aggregate accumulation of data pages led to a memory outage.


User application has been modified to restrict the amount of content returned to the thread-level, per interaction data pages.

​This has reduced memory consumption and has avoided outages.


Published July 27, 2016 - Updated October 8, 2020

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