[TEZ-1075] 0 vertex dags should succeed

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Labels: newbie++
• Assignee: Chen He
• Reporter: Bikas Saha
• Created: 21/Apr/14 21:08
• Updated: 19/Jun/15 23:41

Description

Currently 0 vertex dags fail because of the following code in DAGImpl

    if (numVertices == 0) {
      addDiagnostic("No vertices for dag");
      trySetTerminationCause(DAGTerminationCause.ZERO_VERTICES);
      if (event != null) {
        return DAGState.FAILED;
      }
      return finished(DAGState.FAILED);
    }

IMO a 0 vertex DAG is a legitimate construct and should just pass. Similar to a 0 task vertex. Its essentially a no-op operation.