Eclipse MAT Parsing 11GB Heap dump - Out Of Memory. Unable to parse the heap dump

Question

I was trying to parse the 11GB heap dump using Eclipse MAT and I am getting the following error

  An internal error occurred during: "Parsing heap dump" 

I think the MAT is unable to parse such a huge heap dump. I read some posts and increase the VM configurations to more than 80% of the dump size. Following are my vm configurations

      -vmargs -Xms8192m -Xmx10240m 

and I am still not able to load the dump. I tried with ParseHeapDump.bat with no changes ...

Biggs

I have more large heap dump, just create an ec2 instance to run mat in the vnc. In this case m1.xlarge or m3.2xlarge may be enough. – Tanah

See also #7254517 – Enclosure

In general, you need more memory to parse the heap dump then is the size of the heap dump itself. 150% percent is usually enough in my experience. – Stalker

Answer 1

Keep increasing Xmx till the JVM complains, then increase your swap file size, then increase Xmx again, etc.

At that stage it will take ages because it will be using disk as RAM.

Nyasaland

After posting this question I tried with 12gb of heap and the dump processed but its taking very long to remove the unreachable objects. It started it since more than a day now and its still 34%. So my next question is how to speed up this process? – Biggs

Answer 2

I recently installed Eclipse MAT (Eclipse Memory Analyzer Version 1.9.1) on Mac OS Catalina (10.15.3). I needed to review a 4g heap dump. The default JVM heap size for MAT is 1024m.

I think the easiest way to increase the JVM's heap size is to use a shell window - go to the /Applications/mat.app/Contents/Eclipse/ folder. Then vi MemoryAnalyzer.ini and change -Xmx1024m to your required value, in my case I went with -Xmx10g.

To review the change, restart MAT and go to the help -> About Eclipse Memory Analyzer then click installation details, and look for the entry: eclipse.vmargs=-Xmx10g about 50 lines down.

Spirochaetosis

Answer 3

This setup worked for me.

I also recently installed Eclipse MAT to analyze a 4.85GB heap dump file.

Eclipse Memory Analyzer Version: 1.11.0
MacOS Catalina: 10.15.7
Hardware Memory: 16GB
Heap dump file size: 4.85GB 
Heap dump file type: PHD
Classes: 33.6k
Objects: 4.8m
Class Loader: 575

I changed the MemoryAnalyzer.ini to 14GB as follows:

-vmargs
-Xmx14g

I also confirmed the configuration as follows:

1. Help -> About Eclipse Memory Analyzer 1.11.0
2. Clicked on Installation Details
3. Clicked on Configuration tab
4. Looked for eclipse.vmargs=-Xmx14g.

It took some minutes to load this 4.85 heap dump file.

Note: I unsuccessfully tried Xmx setup with 2g, 4g, 8g, 10g, 12g - all failed with JVM out-of-memory in the Eclipse MAT tool.

Aargau

Answer 4

On the Windows install of Eclipse Photon, I got around the problem by updating the memory parameters in the eclipse.ini file. This was directly under my c:\eclipse folder.

-Xms6g 
-Xmx6g

I tried setting it to 4 gigs for a memory dump that was about 4.1GB and it failed. So, the rule of thumb is to set it to a higher value than the size of the memory dump.

Dole