Eclipse MAT in Docker

Runs Eclipse MAP heap dump analysis in command line. Report will be generated along side the heap dump file.

Basic usage

docker run \
       --mount type=bind,source="$(pwd)",target=/dump \
       docker-mat \
       heapdump-podname-347602788-9l0z9.hprof

One the parsing is done, the reports are ready and just open the hprof file in Eclipse MAT, no parsing is necessary one just navigate the reports.

But Eclipse MAT is not necessary if one want to just consults the report without having to open Eclipse MAT application.

The script currently generates the 3 type of reports that Eclipse MAT can perform, and it’s probably those to look at anyway :

• System overview

• Leak suspects

• Top components

heapdump-podname-347602788-9l0z9_Leak_Suspects.zip
heapdump-podname-347602788-9l0z9_System_Overview.zip
heapdump-podname-347602788-9l0z9_Top_Components.zip

Inside each of these zip files there is a simple HTML structure, that can be opened and navigated in a browser.

> unzip -d leak_suspects-podname-347602788-9l0z9 heapdump-podname-347602788-9l0z9_Leak_Suspects.zip
Archive:  heapdump-podname-347602788-9l0z9_Leak_Suspects.zip
  inflating: leak_suspects-podname-347602788-9l0z9/styles.css
  inflating: leak_suspects-podname-347602788-9l0z9/img/fork.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/nochildren.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/line.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/warning.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/open.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/closed.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/success.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/error.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/corner.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/opened.gif
  inflating: leak_suspects-podname-347602788-9l0z9/img/empty.gif
  inflating: leak_suspects-podname-347602788-9l0z9/toc.html
  inflating: leak_suspects-podname-347602788-9l0z9/index.html
  inflating: leak_suspects-podname-347602788-9l0z9/code.js
  inflating: leak_suspects-podname-347602788-9l0z9/pages/Class_Histogram7.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/Thread_Overview5.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/23.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/Top_Consumers6.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/System_Overview2.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/20.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/System_Properties4.html
  inflating: leak_suspects-podname-347602788-9l0z9/pages/21.html
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i5.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i0.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i3.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i8.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i9.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i2.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i6.gif
  inflating: leak_suspects-podname-347602788-9l0z9/icons/i1.gif
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  inflating: leak_suspects-podname-347602788-9l0z9/icons/i7.gif

In fact when Eclipse MAT is running after it generated the reports, it barely loads these reports in tabs.

While this approach usually suffice but there’s some caveats :

1. These reports are may have links with the mat:// sheme, e.g. mat://query/leakhunter, those links do not work in the browser.

2. Memory since the analyzer runs in a container the process can be a bit more constrained. If the heap dump is 3gb it is necessary to tweak the` JAVA_OPTS` with -Xmx and -Xms but not only! For example if docker is running on OSX it may be necessary to increase hyperkit memory to allow such memory. (Docker > Preferences > Advanced tab > Memory).

Other files are generated along, those allows the UI to navigate through other elements available in the heap dump, and should be kept in order to open the analysis in Eclipse MAT.

heapdump-podname-347602788-9l0z9.a2s.index
heapdump-podname-347602788-9l0z9.domIn.index
heapdump-podname-347602788-9l0z9.domOut.index
heapdump-podname-347602788-9l0z9.hprof
heapdump-podname-347602788-9l0z9.i2sv2.index
heapdump-podname-347602788-9l0z9.idx.index
heapdump-podname-347602788-9l0z9.inbound.index
heapdump-podname-347602788-9l0z9.index
heapdump-podname-347602788-9l0z9.o2c.index
heapdump-podname-347602788-9l0z9.o2hprof.index
heapdump-podname-347602788-9l0z9.o2ret.index
heapdump-podname-347602788-9l0z9.outbound.index
heapdump-podname-347602788-9l0z9.threads

Need more memory

If the parser fails with an OOME in the log, then declare bigger -Xms -Xmx options usually at least of the size of the heap dump. And eventually increase the memory to the matching amount in your Docker settings.

ommand-line arguments:  -consolelog -application org.eclipse.mat.api.parse /dump/heapdump-podname-305475067-cfnp4.hprof org.eclipse.mat.api:suspects org.eclipse.mat.api:overview org.eclipse.mat.api:top_components

!ENTRY org.eclipse.osgi 4 0 2019-05-30 08:58:27.146
!MESSAGE Application error
!STACK 1
java.lang.OutOfMemoryError: Java heap space
...

Analyzing heapDump-edge-api-305475067-cfnp4.hprof
Task: Parsing heapDump-edge-api-305475067-cfnp4.hprof
[Task: Parsing /dump/heapDump-edge-api-305475067-cfnp4.hprof
[
Subtask: Scanning /dump/heapDump-edge-api-305475067-cfnp4.hprof
[
[INFO] Detected compressed references, because with uncompressed 64-bit references the array at 0xd5581fd0 would overlap the array at 0xd5581f80
[....................
[INFO] Wrote threads call stacks to /dump/heapDump-edge-api-305475067-cfnp4.threads
[....................
[INFO] Heap /dump/heapDump-edge-api-305475067-cfnp4.hprof contains 35,434,200 objects
[....................
Subtask: Extracting objects from /dump/heapDump-edge-api-305475067-cfnp4.hprof
Killed
[................................................................................

If the process appears to suffer, it may be due to the GC, but it’s not possible to use jmap if the container has not be started with the following option (Docker 1.18+)

--cap-add SYS_PTRACE

See this issue thread for more details.

Who is it for ?

• People that do not want to download manually Eclipse MAT

• People that do not want to use Eclipse MAT user interface

• People that need to analyze a lot of heap dumps

• People that want to to automate heap dump reports

Licenses

• Eclipse MAT belongs to Eclipse

• Docker belongs to Docker