@Override
      public void apply(FileSinkOperator fsOp) {
        if (fsOp.getConf().isGatherStats()) {
          statKeys.add(fsOp.getConf().getStatsAggPrefix());
        }
      }
Checks if a task can be launched.

@param tsk
         the task to be checked
@return true if the task is launchable, false otherwise
ql/src/java/org/apache/hadoop/hive/ql/TaskQueue.java