Which InnoDB isolation level should be used with Moodle. The default is REPEATABLE READ, is it save, however, to use READ COMMITTED for better performace?
Moodle does not tend to rely on strict transactionality. (It works with MyISAM tables, after all.) So it is probably fairly safe. But worth measuring is some way to make sure it actually makes things faster. If not, safer not to make the change.