https://el.wordpress.org/plugins/query-monitor/
https://el.wordpress.org/plugins/mysql-profiler/

http://php.net/xhprof

http://www.exteon.ro/en/products/php-tools/web3tracer/manual
http://www.exteon.ro/en/products/php-tools/web3tracer/manual/usage/using-kcachegrind/wordpress-example

https://wpperformanceprofiler.interconnectit.com/

https://github.com/soulseekah/wptop
https://spinpress.com/profiling-php-code-wordpress/
http://codeseekah.com/2014/09/05/profiling-php-code-in-wordpress/

===

LIKE P3 WE DO NOT FIND THE DETAIL IN THE PROBLEM
WE DETECT WHERE ONE SHOULD LOOK FOR LOAD AND BLOATS

USEFUL TO EXTRACT MEAN VALUES AND STATISTICS
AS TO WHERE THE BOTTLENECKS ARE
OR WHERE THE OPTIMIZATION IS NECESSARY

===

 - Alert if certain limits are exceeded!!!

 - Check whether installation is setup OK, ie database table exists, 
   but only in the admin area 
   or the plugin settings page

 - Indicate in database which resource consumes the most resources
   a post type, an archive, etc
   the queried object

 - If you put a special ID (identifier) on each request then you will be able to send back browser load statistics to
   the server and associate the backend with the frontend usage.

 - Report database table usage
   Cleanup (periodically? after an amount of rows?)
   Provide a way for manual cleanup

 - Monitor specific urls

 - Aggregate values per type (theme, admin, ajax, cron)
   number of requests

 - Charts! Yes!
   But what kind of charts? Real time? Mean values? Mean values in a specific time window?

 - Daily/monthly/weekly report
   Why not combine it with a total disk usage?

 - Viewer of all requests and sorting.

 - Frontend show resource usage.

===

 - Check if actions return false values
 - Add PHPDoc.