A notion of empty resource is used by plugins like Hive to check if user has the given access to any resource. A special case of this usage is the 'show databases' command in Hive, which checks if the requesting user has 'any' access to any resource in the system. In this case, the tag enricher should attempt to find if the user has been granted access via a tag associated with any resource in the service i.e. any database/table/column. The algorithm to find the tags that match for the given resource can be optimized to handle this special case by simply retuning all the tags associated with all resources in the service - eliminating the need to attempt resource matching.