HPjmeter 4.3 User's Guide

Figure 87 Early Indicator of Possible Memory Leak Using Heap Monitor Display

HPjmeter uses the long term linear upward trends in the heap size after garbage collections to

calculate the presence of memory leaks.

Short-term increases in heap size are normal. HPjmeter measures this rate in MB/hour.

HPjmeter does not report a leak in situations in which the heap size increase is only temporary,

or in situations in which the slope of the fitted line is too small to raise an alarm.

However, sometimes a healthy Java application is diagnosed with a memory leak. When the heap

size returns to its previous range, such an erroneous diagnosis is revoked, reverting to its original

state.

Leak detection accuracy improves over time, so if a memory leak alarm fluctuates on and off, or

in value, you should base your analysis on the present alarm state.

With high leak-rate, you can consider having the IT administrator start another JVM and stop the

old one in a controlled way, in a clustered environment, when the garbage collection percentage

becomes excessive. What is considered excessive depends more on the rate of change of garbage

collection percentage or the estimated number of minutes before the heap will run out.