@Override
  public boolean canExecuteInParallel() {
    // ReplStateLogTask is executed only when all its parents are done with execution. So running it in parallel has no
    // benefits.
    return false;
  }
ReplStateLogTask.

Exists for the sole purpose of reducing the number of dependency edges in the task graph.
ql/src/java/org/apache/hadoop/hive/ql/exec/repl/ReplStateLogTask.java