Moodle course slow to load

An issue with one of our Moodle instances - one of the courses was loading very slowly in Edit Mode, and was timing out. Another issue - the question bank was not loading at all.

1. Question bank issue - The database table prefix_question_statistics showed a(n abnormally?) high number of entries -  that table alone is 49 MB,  with more being added every day. Apparently that was the issue. Statistics was disabled for the question bank, and the question bank started loading again. 

Some suggestions to make the course(s) load faster:

a. Currently, if you click on one of the courses, a huge page, with many images, for all weeks, loads in the browser. We can make it load a bit faster using Cloudflare, but such a large page is bound to cause problems with older computers / machines with less RAM / on slower networks / etc. It would be better to show a collapsed view, with each week opening up only on clicking. (the collapse all link on the top right). Or on separate pages.

b. Use jpg, of quality = 70 to 75 instead of png. 

c. Turn on cloudflare proxying. 

d. Clicking on question bank also loads up 1000 questions at once. This would cause problems as the number of questions / size of each question increase. It would be desirable to load up fewer questions - maybe 100 at a time as with the link at the bottom, "Show 100 at a time" - I have clicked it now. 

2. Course not loading / slow to load - Further troubleshooting tips -
Moodle in English: Very large course takes a minute to load unless "editing" is on

" It's almost always because somebody is trying to build the learning material on the course page itself rather than in activities/resources "behind" the page. There's nothing wrong with that, of course, but it's does have an effect.

We had a course with 120 videos embedded in labels on the course page. It took 10 minutes plus to load - even on a good connection."

So, probably not a good idea to embed all your content on the course page itself, they should be "activities/resources behind the page".


Also, another person says:
"To track down the culprit I usually switch to one section per page. With one section per page, only the content for that pages loads, so some sections will load normally, but your dragger will still drag."

How to show one topic per page:
Course format types in Moodle · Technology Help · Lafayette College

 

(Apparently the "embedding videos in labels" was one of the issues. Another suggestion which S passed on was: 

another way to improve performance overall is to move out three folders namely (cache, localcache and temp) out of moodle data folder. Here is a tutorial for the same.  https://youtu.be/qXnSlwYzDfU )