[HBASE-19337] AsyncMetaTableAccessor may hang when call ScanController.terminate many times

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0-beta-1, 2.0.0
• Assignee: Guanghao Zhang
• Reporter: Guanghao Zhang
• Created: 23/Nov/17 09:24
• Updated: 01/Aug/18 06:22
• Resolved: 25/Nov/17 11:55

Description

Code in ScanControllerImpl.

    private void preCheck() {
      Preconditions.checkState(Thread.currentThread() == callerThread,
        "The current thread is %s, expected thread is %s, " +
            "you should not call this method outside onNext or onHeartbeat",
        Thread.currentThread(), callerThread);
      Preconditions.checkState(state.equals(ScanControllerState.INITIALIZED),
        "Invalid Stopper state %s", state);
    }

    @Override
    public void terminate() {
      preCheck();
      state = ScanControllerState.TERMINATED;
    }

So if call terminate on a already terminated scan, it will throw IllegalStateException.