@Override
  public void drop_dataconnector_req(final DropDataConnectorRequest dropDcReq) throws NoSuchObjectException, InvalidOperationException, MetaException {
    boolean success = false;
    DataConnector connector = null;
    Exception ex = null;
    RawStore ms = getMS();
    String dcName = dropDcReq.getConnectorName();
    boolean ifNotExists = dropDcReq.isIfNotExists();
    boolean checkReferences = dropDcReq.isCheckReferences();
    startFunction("drop_dataconnector_req", ": " + dcName);
    try {
      connector = getMS().getDataConnector(dcName);
      DataConnectorProviderFactory.invalidateDataConnectorFromCache(dcName);
    } catch (NoSuchObjectException e) {
      if (!ifNotExists) {
        throw new NoSuchObjectException("DataConnector " + dcName + " doesn't exist");
      } else {
        return;
      }
    }
    try {
      ms.openTransaction();
      // TODO find DBs with references to this connector
      // if any existing references and checkReferences=true, do not drop

      firePreEvent(new PreDropDataConnectorEvent(connector, this));

      if (!ms.dropDataConnector(dcName)) {
        throw new MetaException("Unable to drop dataconnector " + dcName);
      } else {
/*
          // TODO
          if (!transactionalListeners.isEmpty()) {
            transactionalListenerResponses =
                MetaStoreListenerNotifier.notifyEvent(transactionalListeners,
                    EventType.DROP_TABLE,
                    new DropTableEvent(tbl, true, deleteData,
                        this, isReplicated),
                    envContext);
          }
 */
        success = ms.commitTransaction();
      }
    } finally {
      if (!success) {
        ms.rollbackTransaction();
      }
/*
        if (!listeners.isEmpty()) {
          MetaStoreListenerNotifier.notifyEvent(listeners,
              EventType.DROP_TABLE,
              new DropTableEvent(tbl, success, deleteData, this, isReplicated),
              envContext,
              transactionalListenerResponses, ms);
        }
 */
      endFunction("drop_dataconnector", success, ex);
    }
  }
Checks whether the repl.last.id is being updated.
@param oldDb the old db object
@param newDb the new db object
@return true if repl.last.id is being changed.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/HMSHandler.java