Loading a large hprof into jhat
Solution 1
I would take a look at the eclipse memory analyzer. This tool is great, and I have looked at several Gig heaps w/ this tool. The nice thing about the tool is it creates indexes on the dump so it is not all in memory at once.
Solution 2
Use the equivalent of jhat -J-d64 -J-mx16g myheap.hprof
as a command to launch jhat, i.e., this will start jhat in 64-bit mode with a maximum heap size of 16 gigabytes.
If the JVM on your platform defaults to 64-bit-mode operation, then the -J-d64
option should be unnecessary.
Solution 3
I had to load a 11 GB hprof file and couldn't with eclipse memory analyzer. What I ended up doing was to write a program to reduce the size of the hprof file by randomly removing instance information. Once I got the size of the hprof file down to 1GB, I could open it with eclipse memory analyzer and get a clue on what was causing the memory leak.
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Comments
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liam almost 2 years
I have a 6.5GB Hprof file that was dumped by a 64-bit JVM using the
-XX:-HeapDumpOnOutOfMemoryError
option. I have it sitting on a 16GB 64-bit machine, and am trying to get it into jhat, but it keeps running out of memory. I have tried passing in jvm args for minimum settings, but it rejects any minimum, and seems to run out of memory before hitting the maximum.It seems kind of silly that a jvm running out of memory dumps a heap so large that it can't be loaded on a box with twice as much ram. Are there any ways of getting this running, or possibly amortizing the analysis?
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rogerdpack over 6 years
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liam over 14 yearsThis worked. I actually tried it before with some smaller heap dumps and it really didn't give me any helpful info, but once i got it in with the HeapDumpOnOutOfMemoryError hprof it finally pointed out the exact problem.
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BeeOnRope over 10 yearsCare to share the tool or details how how to write a similar one?
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rogerdpack about 9 yearsUnfortunately MAT still used quite a lot of RAM for me ["failure java heap space"], see stackoverflow.com/questions/7254017/…