Thread Dumps and Heap Dumps on Linux

Dan Robichau

November 15, 2023 17:52

Overview

Sometimes during the course of troubleshooting an issue thread dumps and/or heap dumps will be needed.

Environment

XL Deploy, XL Release, Linux, Unix, Java

Generate a Thread Dump

Identify the java process that XLD/R is running in:
```
ps -ef | grep java
```
Use the process ID from the above to generate a thread dump:
```
kill -3 <pid>
```
This won't kill the process as long as you have included the -3 option

Generate a Heap Dump

Identify the java process that XLD/R is running in:
```
ps -ef | grep java
```
Use the process ID from the above with a tool called jmap (bundled with JDKs):
```
$JAVA_HOME/bin/jmap -dump:format=b,file=heap.bin <pid>
```

Additional Information

These are the simplest ways to get dumps and work well with the out of the box configuration of XLD/R. If you have trouble with the above, there are many tools for getting these dumps.