TO TAKE A THREAD DUMP

• We want to take ten thread dumps every few seconds (maybe 5 seconds apart) so that we can analyze the work of the SymmetricDS instance over time.

• Run jcmd command from the command line on the server running the SymmetricDS instance. This will show the Java processes and their process IDs that are currently running.

# jcmd

3927 sun.tools.jcmd.JCmd
1421 /Users/philipmarzullo/symmetric/lib/symmetric-wrapper.jar exec /Users/philipmarzullo/symmetric/conf/sym_service.conf
1422 org.jumpmind.symmetric.SymmetricLauncher --max-idle-time=90000 --no-log-console

• The line that contains the org.jumpmind.symmetric.SymmetricLauncher class running as the main is the one that you are interested in.

• Run the following command every 5 seconds 10 times.

jstack -l 1422 >/tmp/threaddump.`date +"%Y-%m-%d-%T"`

• Find the files

ls -l /tmp/threaddump.*

-rw-r--r--  1 philipmarzullo  wheel  54233 Dec 20 09:07 /tmp/threaddump.2019-12-20-09:07:57
-rw-r--r--  1 philipmarzullo  wheel  54232 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:01
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:06
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:10
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:16
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:21
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:27
-rw-r--r--  1 philipmarzullo  wheel  55337 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:32
-rw-r--r--  1 philipmarzullo  wheel  55336 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:38
-rw-r--r--  1 philipmarzullo  wheel  55336 Dec 20 09:08 /tmp/threaddump.2019-12-20-09:08:43