We have just noticed that some submissions to the assignment module (can be files, or online text) are invisible to the instructor (1.9.5 and 1.9.8)
Student can see his own submission just fine.
Instructor/admins can see all other submissions in the same assignment OK as well, but not this particular one, unless(!) they re-sort assignment submissions page by any other column, e.g. by Last Modified.
We found out that the cause of the bug is multiple entries into the database.
We have tried to reproduce the bug, but we were not able to. It seems that certain conditions need to be just right for the bug to happen. It might be server lagging, or pushing the submit button at a specific interval.
Querying the database found 67 duplicate entries by users from 200,000 entries in the assignment_submissions table that have been submitted in total. So, it seems to be a very rare bug. However, it does happen
We have encountered similar issue with the gradebook, when instructor was deleting columns, and managed to click submit button twice.
Anyone encountered the same issue? Or is it just us? Any code tips?
We do not want to change anything in the database to fix existing problems, we would rather fix the cause