In some cases, you may need more information about the behavior of the Indexima Core Engine (Galactica).

In order to do this you can retrieve a "thread dump" of the Galactica instance.

You can retrieve a thread dump like this:

  • Log in on a master with the same user you used to run Indexima
  • Use the jps tool to determine the pid of the Galactica instance (NodeServer)

On HortonWorks


It will return the following list:

9536 NodeServer
17457 GaYarnLauncher
6984 Jps
18392 NodeServer
10381 Visualdoop
8911 GaYarnLauncher

If you have many NodeServer instances, you can search for the one you want to investigate by doing a pstree and looking for the applicationId.

  • When you have the pid of the correct NodeServer :

On Hortonworks

/usr/jdk64/jdk1.8.0_112/bin/jstack (PID of NodeServer)
  • You can now redirect the output into a file.

How to get a "thread dump" at regular intervals

On Hortonworks :

  • Create a directory.
  • Launch the thread dump every 300 seconds, 10 times.
for I in `seq 0 10` ; do /usr/jdk64/jdk1.8.0_112/bin/jstack (PID of NodeServer) > threaddump.$(date +"%Y-%m-%d_%H:%M:%S").txt ; sleep 300 ; done

This command uses a lot of processing power so be careful not to execute this command too quickly.