When duplicating module the course cache is rebuilt twice

Duplicate last module in a section Refresh course page and make sure the duplicated module is still in the correct position Duplicate another module (not the last one) Refresh course page and make sure the duplicated module is right below the original module If you want to test performance win: Create a course with many modules Open course page in editing mode Add 'logall' => 1 to the $CFG->dboptions in the config.php Duplicate a module Count the number of new records in mdl_log_queries table Revert the commit Duplicate a module Count the number of new records in mdl_log_queries table - it is much larger (the bigger the course the larger is the difference) Remove 'logall'