Doesn't look like a performance problem. Since nobody replied here's a quick thought. The moderator might want to move the discussion to proper forum, once the issue is resolved.
> Adhoc task failed: core_course\task\course_delete_modules,Coding error detected, it must be fixed by a programmer: The course module 221 could not be deleted. #0
Is it possible that the task was delayed and you deleted the course without waiting? Then just removing the task from the queue or, more risky, deleting the corresponding line in the database could help.
> Adhoc task failed: core_course\task\course_delete_modules,Coding error detected, it must be fixed by a programmer: The course module 221 could not be deleted. #0
Is it possible that the task was delayed and you deleted the course without waiting? Then just removing the task from the queue or, more risky, deleting the corresponding line in the database could help.