def node_properties
      collection = connection[node_properties_collection]
      result = {}
      collection.find.batch_size(999).each do |values|
        id = values.delete('_id')
        result[id] = values
      end
      result
    end
def node_properties
      collection = connection[node_properties_collection]
      result = {}
      collection.find.batch_size(999).each do |values|
        id = values.delete('_id')
        result[id] = values
      end
      result
    end
initialize access to mongodb

 You might want to adjust the logging level, for example:
   ::Mongo::Logger.logger.level = logger.level

 @param connection        mongodb connection, should already be switched to correct database
 @param nodes             symbol for collection that contains nodes with their facts
 @param node_properties   symbol for collection for nodes with their update timestamps
 @param meta              symbol for collection with update metadata
 get all nodes and their update dates