code: public static Deferred<Boolean> metaExistsInStorage(final TSDB tsdb, 
        final String tsuid) {
      final GetRequest get = new GetRequest(tsdb.metaTable(), 
          UniqueId.stringToUid(tsuid));
      get.family(FAMILY);
      get.qualifier(META_QUALIFIER);
      
      /**
       * Callback from the GetRequest that simply determines if the row is empty
       * or not
       */
      final class ExistsCB implements Callback<Boolean, ArrayList<KeyValue>> {
  
        @Override
        public Boolean call(ArrayList<KeyValue> row) throws Exception {
          if (row == null || row.isEmpty() || row.get(0).value() == null) {
            return false;
          }
          return true;
        }
        
      }
      
      return tsdb.getClient().get(get).addCallback(new ExistsCB());
    }
docs: Determines if an entry exists in storage or not.
  This is used by the UID Manager tool to determine if we need to write a
  new TSUID entry or not. It will not attempt to verify if the stored data is
  valid, just checks to see if something is stored in the proper column.
  @param tsdb  The TSDB to use for storage access
  @param tsuid The UID of the meta to verify
  @return True if data was found, false if not
  @throws HBaseException if there was an issue fetching