Gordon,
I see that this thread is a couple of years old but it pertains directly to an issue that has cropped up for me this week as I've been using HotPot to give finals for my students as our term ends.
I've been using HotPot and these exact same jqz, jmatch, and jclz files for over a year on a couple of different moodle installations and have never had any of these problems before. This week, I've seen all the issues this thread discusses. In particular:
This morning, I took a quiz myself. No other users are on line and I got this error when submitting a jmatch:
Hot Potatoes attempt record 516 could not be accessed:
This appears to be the db overload issue you discussed, but nothing else is going on in MySQL right now except for my single HotPot Quiz. I've had 45 students taking a quiz at one time and never seen this before.
Yesterday, I watched several students finish a quiz, show the 'results have been saved screen' and my HotPot report show that their quiz is 'in progress'. More importantly, the details of their attempt will only show some random percentage of the total questions. So out of 48 questions, the attempt record will show only 20 or so and that perhaps the student has answered only 15 of those. This is after I clearly watched them finish the entire test. I also saw scores change with time. For example, I watched a student finish and get a score of 94. However, my report would show perhaps and 82, but then five minutes later show maybe a 79. After about 10 minutes the scores finally stablized and stopped changing. I think MySQL has Alzheimer's.
Out of approximately 74 attempts this week, my reports show only 3 completed. I know that all the attempts were completed because I set up my jqz so that EVERY answer is correct (wrong answers score 0%) so that students won't get 'trapped' in the quiz because they had wrong answers. Even with this protection, some times students still forget to answer questions and I have walk through the entire quiz with them to find whatever is holding them back. I'm very keen on making sure my students don't close the quiz window when they think they are done. I instruct them to wait for it to kick them back to the main moodle class page or their test will be invalid.
Clearly something unhealthy is going on with my MySQL db, but what could it be? This server has been running smoothly for about year and has had no recent configuration changes. I did a restart last night in hopes that might make a change, but I still got the above mentioned error. The error log for MySQL is completely empty.
As a side note, when I set up all these quizzes two or three weeks ago and tested them myself, they worked fine. I also had one student do a linked series of five files (quiz, match, cloze, cross, and quiz) and it worked flawlessly. This was the same set of files that failed on me this morning.
I'm running Moodle 1.9.8 Build 20100325
(Edited by Gordon Bateson - original submission Wednesday, 9 June 2010, 06:52 AM)