tree 54f6e9d9c9bca0fdb1c0d1dce17832c2d321c5e5
parent f89c59b392a3ffd93df05a9d0414bfa8ba37edf7
author Chris Westin <cwestin@yahoo.com> 1427239293 -0700
committer Jacques Nadeau <jacques@apache.org> 1427343083 -0700

DRILL-2547: Don't allow Drill to shut down while queries are still executing
This will cause Drillbit.close() to block until all currently executing
fragments have completed.

WorkManager
- added waitForExit() and indicateIfSafeToExit(), which use a latch to
  wait to shut down if there are active fragments
  - waitForExit() times out after 5 seconds

Drillbit
- call WorkManager.waitForExit() in close()