Memory Analyzer can currently work with three dump types:
- IBM Portable Heap Dump (PHD): This proprietary IBM format contains
only the type and size of each Java object in the process, and the
relationships among the objects. This dump-file format is
significantly smaller than the other formats and contains the least
information. The data is usually sufficient, though, for diagnosing
memory leaks and getting a basic understanding of the application's
architecture and footprint.
- HPROF binary dump: The HPROF binary format contains all the data
present in the IBM PHD format as well as the primitive data held
inside the Java objects, and the thread details. You can look at the
values held in fields inside the objects and see which methods were
being executed at the time the dump was taken. The additional
primitive data makes HPROF dumps significantly larger than
PHD-format dumps; they are approximately the same size as the used
- IBM system dumps: When the IBM Java runtime is being used, the
native operating-system dump file — a core file on AIX® or Linux, a
minidump on Windows®, or a SVC dump on z/OS®— can be loaded into
Memory Analyzer. These dumps contain the entire memory image of the
running application — all the information and data in the HPROF
format, as well as all of the native-memory and thread information.
This is the largest and most comprehensive dump-file format.
Both IBM dump types are available only with the Diagnostic Tool Framework for Java (DTFJ) plug-in installed