How to analyse a .phd heap dump from an IBM JVM

If you have been handed a .phd file which is a dump of the heap of an IBM Java virtual machine, you can analyse it using the Eclipse Memory Analyzer Tool (MAT), but you must install the IBM Monitoring and Diagnostic Tools first.

Download MAT from I suggest the Standalone version.

Unzip it and run the MemoryAnalyzer executable inside the zip. Add an argument to control how much memory it gets e.g. to give it 4GB:

./MemoryAnalyzer -vmargs -Xmx4g

Once it’s started, go to Help -> Install new software.

Next to “Work with” paste in the URL for the IBM Developer Toolkit update site:

Click Add…

Type in a name like “IBM Monitoring and Diagnostic Tools” and click OK.

In the list below, an item should appear called IBM Monitoring and Diagnostic Tools. Tick the box next to it, click Next, and follow the wizard to accept the license agreements and install the toolkit.

Restart Eclipse when prompted.

Choose File -> Open Heap Dump and choose your .phd file. It should open in MAT and allow you to figure out who is using all that memory.

9 thoughts on “How to analyse a .phd heap dump from an IBM JVM”

  1. When I tried to update ini file to 4g, it did not open MAT. I needed to reset to what it was that is 1024m and then when I opened this phd file, it gave an error that Error opening heap dump is encountered. Does someone know what to do?

  2. Very helpful , thanks.

    Hi Poonam
    If you are on windows, type
    in the search , go into command prompt. In the command prompt , change directory (cd) to the directory that MemoryAnalyser.exe is in. Then type
    MemoryAnalyzer -vmargs -Xmx4g
    and press enter.

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