# File lib/new_relic/agent/instrumentation/active_record_helper.rb, line 229
          def host(config)
            return UNKNOWN unless config

            configured_value  = config[:host]
            adapter = PRODUCT_SYMBOLS[config[:adapter]]
            if configured_value.nil? ||
              postgres_unix_domain_socket_case?(configured_value, adapter)

              LOCALHOST
            elsif configured_value.empty?
              UNKNOWN
            else
              configured_value
            end

          rescue => e
            NewRelic::Agent.logger.debug "Failed to retrieve ActiveRecord host: #{e}"
            UNKNOWN
          end