Logger to log execution sql time (available on DEBUG level):

You could always enable by (the root appender will be used):

<logger name="NativeCriteriaPerformance" level="DEBUG" />

If you want add additional log output (system log or separate file) configure the appender too:

<logger name="NativeCriteriaPerformance" level="DEBUG">
   <appender-ref ref="stdout" />
</logger>