How to analyze a large heapdump?

Question

Is there a tool to analyze a large Java Heap dump (2GB), if one only can assign 1,5GB to the JVM? I can't believe the dump must be fully loaded into memory to be analyzed...

Eclipse MemoryAnalyzer fails, and the IBM tool also.

Do I need to use command line tools here now?

Answer 1

If it's a dev server, restrict the max heap size to something a 32-bit OS can handle. If it's in production, demand a 64-bit OS! If you can't get that, you can run jhat on the server (it has a web interface you can access on your own PC).

Answer 2

One solution is to install the MAT tool on the remote server and generate an HTML output of the analysis to download and view locally. This saves the headache of attempting to get X Windows installed on the remote machine and get all of the ssh tunneling sorted out (which is of course an option as well).

First, download and install the stand-alone Eclipse RCP Application. Then transfer to your server and unpack. Then determine how large the heap dump is and, if necessary, modify the MemoryAnalyzer.ini file to instantiate a JVM with enough RAM for your heap dump.

In this example, I have an 11GB heap dump and have modified the last two lines (adding -Xms)

-startup
plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.300.v20150602-1417
-vmargs
-Xmx16g
-Xms16g

Do an initial run to parse the heap dump. This will generate intermediary data that can be used by subsequent runs to make future analysis faster.

./ParseHeapDump.sh /path/to/heap-dump

After that completes, you can run any of a number of different analysis on the data. The following is an illustration of how to search for memory leak suspects.

./ParseHeapDump.sh /path/to/heap-dump org.eclipse.mat.api:suspec