This is similar to example, but it illustrates the use of the coordinator
  database.
To demonstrate, do:  make check    [Checkpoints every 5 seconds]
After killing it, try:  ./dmtcp_restart_script.sh

This uses the database service of DMTCP.  At checkpoint or restart time,
each process can install a key-value pair, and then optionally query a value
for a given key.  This type of facility can be used internally by DMTCP
for such things as registering an old_pid/new_pid pair at restart time,
and then querying the new_pid of a remote process given its old_pid.
