Question & Answer
Question
How does one trace Large Object Allocation in Websphere?
Answer
When debugging Java Heap fragmentation problems, it can be helpful to find the stack traces of the thread that makes large allocation requests.
To achieve this in WebSphere:
1. Open the Administrative Console.
2. Select Servers > Application Servers > server_name > Java and Process Management > Process Definition > Environment Entries > New.
3. In Application Server 6.0.2 or greater, navigate in the Administrative Console to: Servers >Application servers > server_name > (Expand Java and Process Management) > Process Definition > Custom Properties > New
4. Add the following Name/Value pairs:
Name: ALLOCATION_THRESHOLD
Value: value
Name: ALLOCATION_THRESHOLD
Value: value
5. Make sure that you save your changes to the master configuration and restart the Application Server.
If you set this option to a value nnn (bytes), whenever an allocation request is made for an object size >= nnn (bytes), the Java stack trace corresponding to the thread requesting the allocation is printed into the standard error log.
This will be helpful to find out any Large Object Allocation requests.
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Historical Number
FAQ3454
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Document Information
Modified date:
16 June 2018
UID
swg21519838