After following the AsyncExecutionDbTest I was able to get Async execution to work.
I then modify the testcase a little such that I fork out 3 async nodes and hoping they will run in parallel. But they run in serial.
I looked at the code for CommandExecutorThread, it seems the thread will consume the messages one by one. Thus the serial execution.

I created two CommandExecutorThread and hoping the thread pool will consume the messages in turns. But the Command Executor does not remove the message from the queue until it has finished executing it. The two threads simply repeats the message.

Can you suggest a solution to this?

Thanks.