In the author tab, there is a SQL query to retrieve the learn resources. It has a relatively complex access check. This part need to be optimised. The issue is especially for administrators of large instances with more than 10'000 resources.
To do (checked with more than 40'000 resources):
- Replace the sub select in with exists (from unknown number of minutes to 3 seconds)
- Compact the check in one sub select instead of three (it's really 3 times quicker and a little more)
- Use an inner join in the sub select instead of the cross join (40% quicker)
- AND fix the comma bug for the author sub select