Actually its seems that there is no activity captured in the /var/log/postgresql/postgresql-9.5-main.log
root@Master:~# tail -f /var/log/postgresql/postgresql-9.5-main.log
2018-09-19 17:32:41 IST [325-9] dhis@up HINT: In a moment you should be able to reconnect to the database and repeat your command.
2018-09-19 17:32:41 IST [31038-1] dhis@dhis WARNING: terminating connection because of crash of another server process
2018-09-19 17:32:41 IST [31038-2] dhis@dhis DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2018-09-19 17:32:41 IST [31038-3] dhis@dhis HINT: In a moment you should be able to reconnect to the database and repeat your command.
2018-09-19 17:32:41 IST [324-49] dhis@up WARNING: terminating connection because of crash of another server process
2018-09-19 17:32:41 IST [324-50] dhis@up DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2018-09-19 17:32:41 IST [324-51] dhis@up HINT: In a moment you should be able to reconnect to the database and repeat your command.
2018-09-19 17:32:41 IST [27616-3] dhis@up WARNING: terminating connection because of crash of another server process
2018-09-19 17:32:41 IST [27616-4] dhis@up DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2018-09-19 17:32:41 IST [27616-5] dhis@up HINT: In a moment you should be able to reconnect to the database and repeat your command.