Weird - attempt finish time not accurate - lost answers

Weird - attempt finish time not accurate - lost answers

от François Lizotte -
Number of replies: 4
Снимка на Particularly helpful Moodlers

Hello,


Here's what was reported to me and remains a real puzzle so far.

Under Moodle 2.8

A quiz is available between April 19th and April 26th. It lasts for 3 hours and is set so that attempts are sent automatically when time expires. It has 23 questions: 18 are manually graded and 5 are automatic (true/false). Nothing too exotic so far.


The teacher says that some of the students answers were lost. It really looks like it's true. It seems that the problem occured when he marked the manual questions this mornings.


Now, the only unusual thing I observed so far is that the "Attempt finished" time differs from one question to the other in the same attempt. As you can see in the capture below, 19/04/16 at 21:55 really makes sense. But 16/05/16 at 6:09 corresponds to the time the teacher was grading some of the question.

How in the world a same attempt (and there is only one allowed) could have two different finish dates?

capture


Next step will be to restore a backup to confirm that all answers were answered. In the meantime, if anyone has a clue, please help me.


François

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In reply to François Lizotte

Re: Weird - attempt finish time not accurate - lost answers

от Tim Hunt -
Снимка на Core developers Снимка на Documentation writers Снимка на Particularly helpful Moodlers Снимка на Peer reviewers Снимка на Plugin developers

I think you are leaping to conclusions, but putting too much trust in the words that are displayed in that history table.

The history table is an attempt to display, in somewhat human-readable form, the detailed data that is stored about each attempt in the database. However, the translation into human-readable form is imperfect. For example, where it says that Question 7 was 'Started' twice, it does not really mean that. It says that whenever a blank answer is saved (which normally only happens when an attempt is started).

(We ought to try to improve the history display.)

A quiz attempt has only one start and one end time, and you can see that at the top of the review attempt page, or in the quiz reports. (It is stored in the quiz_attempts table in the database.)

The other thing I note is that 21:55 is less than 3 hours after 19:03. Therefore, the student stopped work before Moodle auto-submitted the attempt. In that case, you need to look at the quiz setting for what happens when time expires. I assume that is set to say attempts should be submitted automatically? If so, the attempt should have been submitted the next time cron ran, after time expired.

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In reply to Tim Hunt

Re: Weird - attempt finish time not accurate - lost answers

от François Lizotte -
Снимка на Particularly helpful Moodlers

Here's the quiz header. I assume the student submitted the quiz before reaching 3 hours. So, it was not sent through a cron job.

quiz header

Thank you so much for your time, Tim. 

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In reply to François Lizotte

Re: Weird - attempt finish time not accurate - lost answers

от François Lizotte -
Снимка на Particularly helpful Moodlers

I confirm that some answers were lost. We retreived a back up to compare. 

We also noticed a common detail among the attempts which had lost answers. Two multiple choice questions have an extra answer choice labelled "This choice was deleted after the attempt was started." But both questions were not modified after the quiz start date. This is also pretty strange.




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In reply to François Lizotte

Re: Weird - attempt finish time not accurate - lost answers

от Tim Hunt -
Снимка на Core developers Снимка на Documentation writers Снимка на Particularly helpful Moodlers Снимка на Peer reviewers Снимка на Plugin developers

Something extremely weird is going on with your site. I cannot think how normal execution of the code could produce the symptoms you are seeing, (even allowing for the type of errors that might be caused by typical bugs). The only way you can get to the "This choice was deleted after the attempt was started." message is if the question definition currently in the database is different from how the question was when the quiz attempt was started.

Have you looked through the server logs, and the Moodle logs, to find all accesses to this quiz, and the questions in it?

What caching have you got set up (a particular candidate would be the set-up for the 'Question definition' cache). If that cache is set up wrong, then I suppose that might possibly lead to these symptoms.

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