Kevin Grigorenko's IBM WebSphere SWAT Blog

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Be careful when diagnosing Java memory leaks

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I was recently at a customer who believed that they had a Java memory leak. They compared heapdumps and couldn't find anything. They had experienced production OutOfMemoryErrors (OOMs) before (for a different reason), and they were so worried about what they perceived, that they increased the maximum heap size to 4GB so that the JVM could handle a day's worth of work, and then they put in a process to restart the JVMs every night. At a first glance of verbose garbage collection, I agreed with them (loaded in the wonderful Garbage... [More]

How to compare verbose garbage collection from two different runs using GCMV

kgibm Visits (2841)

Garbage Collection and Memory Visualizer (GCMV) is a great tool to visualize verbosegc and it is available for free in the IBM Support Assistant . One of its lesser well known features is the ability to compare verbosegc from two different JVM runs. This is particularly useful if you changed something and you want to see the effect. First, load the baseline verbosegc as normal. Next, right click anywhere in the plot area and click 'Compare File...': Next, ensure that the X-axis uses a relative format such as hours, instead of date. Otherwise,... [More]

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