Custom reports are inefficient in requesting persistent element data

Automated (both Behat & PHPUnit) will test everything still works

Manual test prerequisites

1. MySQL (or the knowledge to enable query logging on another DB )
   • Root CLI access to database

Manual test

1. Log in to MySQL terminal as root user, issue the following commands:

   mysql> SET global log_output = 'FILE';

   Query OK, 0 rows affected (0.00 sec)

   mysql> SET global general_log_file='/tmp/mysql.log';

   Query OK, 0 rows affected (0.01 sec)

   mysql> SET global general_log = 1;

   Query OK, 0 rows affected (0.00 sec)

   mysql> quit

   Bye

2. Tail the resulting log file:

   $ tail -f /tmp/mysql.log

3. Log in to Moodle as admin
4. Navigate to Reports from user menu
5. Create new report from Users report source
   • Include default setup
6. Examine the DB query log for the last page request
   • Confirm there is only one logged query matching FROM m_reportbuilder_column (down from ~10)
   • Confirm there are only two logged queries matching FROM m_reportbuilder_filter (down from ~7)
   • Note: replace m_ in table names with appropriate $CFG->prefix according to your own site