We are not experiencing any load/performance issues with any other functions, including functions that have images such as assignments, web pages, forums etc. The issues seem to be related the quiz function. We recently migrated our system to a new server as outlined above. Any direction would be appreciated.
Can we get some more detail of the architecture. Is this a single machine? Is it a VM? Anything else you can think of. What, if anything, have you done to tune Apache and Postgres? What monitoring have you got (e.g. munin) so that you can see if anything odd is happening during quizzes? Do you have any non-core quiz questions?
On the face of it (from the information given) there's nothing jumping out that would explain this, so it's going to be something you haven't told us?
How did you test the performance, how large is your database (in memory?) and do you use a caching server like Redis or Memcache?
Thanks for following up. We identified the issue as we had moved servers and the Postgres autovacuum was off. We now have it configured to run daily.
Mind to share what is the issue and how you have solved it? Our university faced the quizzes slow issue as well, but we're clueless now. Appreciate if you can share some tips here.