public void initializeNumOfDrivers(int numOfDrivers) {
    // initialize with the num of Drivers
    allDriversClosed = new CountDownLatch(numOfDrivers);
  }
Increase the usage reference of filePath of job id. Before the invoking of this method, <code>
this.setqueryIdForCurrentRequestThread</code> has been invoked, so <code>
sealedFilePathsMap.get(queryId)</code> or <code>unsealedFilePathsMap.get(queryId)</code> must
not return null.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/fragment/FragmentInstanceContext.java