Very bad gradebook performance (Moodle 2.8 and 2.9)

Very bad gradebook performance (Moodle 2.8 and 2.9)

Ewout ter Haar -
Vastausten määrä: 7
Our Moodle 2.8 site has become very difficult to use for teachers and admins due to the very long time it takes to re-calculate the gradebook (minutes). The gradebook is also recalculated when putting tutors in cohorts and in many other situations.

Context: Moodle 2.8.8 (i.e., post 2.8.4), MySQL, courses with 300 studentes * 100 gradeitems + complicated categories and aggregations.

Result of making 1 change: DB reads/writes: 70868/43297 DB queries time: 120.40607. Almost 100k queries? What's it doing?! Why 3 queries per grade? If I change a weight (say), surely I don't need to update or select all grades, I only need to touch the aggregations, right?

I thought maybe something was wrong with our database (this site is upgraded continuously since M2.2), so I installed a Moodle 2.9.2, created a course with a 1000 students and 10 gradeitems *with grades* (this is essential, I used the patch from MDL-47911).

Result of making a change: 29306/21018 DB queries time: 41.78441 secs So, again, 3 or 4 queries and updates per grade.

Is there anything I can do? This really makes our instances of Moodle 2.8 very difficult to use. I wonder if nobody else is seeing this: there must be a lot of Moodle admins with 100s of students and 10s of gradeitems. Maybe I'm overlooking something obvious? 

I notice MDL-47911 is closed and that development of MDL-48838 and MDL-48839 seem to have stalled. There's also MDL-49324 .



Vastaus Ewout ter Haar

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

Helen Foster -
Kuva: Core developers Kuva: Documentation writers Kuva: Moodle HQ Kuva: Particularly helpful Moodlers Kuva: Plugin developers Kuva: Testers Kuva: Translators

Hello Ewout,

I am sorry to hear about your very bad gradebook performance. Unfortunately I can't suggest anything that you can do, however I have commented on the unresolved issues that you mention in the hope that developers will reply.

Vastaus Helen Foster

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

Ewout ter Haar -

Thanks, Helen. I posted it here to see if other people with large gradebooks had similar experiences. Maybe I'll take it to the developer forum later.

By the way, something I did not mention was this post suggesting turning of class averages ("show column averages"). That may be helpful for people who find this post via google.

I did that, but the problem is not the displaying of the gradebook, it's the recalculation that takes place everytime something happens (putting tutores in a cohort, recalculating a quiz, changing a weight, etc. etc.).

Oh, here's another ticket MDL-50773 reporting the same issue.


Vastaus Ewout ter Haar

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

Stephen Bourget -
Kuva: Core developers Kuva: Plugin developers Kuva: Testers

There are two other issues you may be interested looking at MDL-51498 and MDL-51584.  MDL-51498, which was fixed yesterday, helps address the number of queries during a regrade. MDL-51584 currently under development focuses on the speeding up the regrade operation.


-Steve

Vastaus Ewout ter Haar

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

Nate Baxley -

I can second that this is a problem.  We've been hoping it was just a few problem instructors, but we're digging in now to find a solution because our large courses are almost unusable in some cases.  Especially when calculated grade items are concerned.  I'll be looking over the tickets mentioned.

Vastaus Ewout ter Haar

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

David Monllaó -

Thanks for sharing your case Ewout.


About MDL-48838 and MDL-48839, I didn't have time to return to them, they will be only master and not ready until 3.1, although the good news is that the issues Stephen commented about (MDL-51498 and MDL-51584) are getting integrated (not 100% sure if MDL-51584 will be backported though) you could try latest 2.8 weekly as MDL-51498 is already integrated.

Vastaus Ewout ter Haar

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

David Monllaó -

Ewout, another important one MDL-51514, this should land in stables, not only master

Vastaus David Monllaó

Re: Very bad gradebook performance (Moodle 2.8 and 2.9)

Ewout ter Haar -

Very encouraging that there is active interest and movement to resolve this issue. We updated to 2.8.8+ and also applied the patch from MDL-51514 (which should be integrated soon). In our tests, this led to a 20-30% speedup of the re-calculation of one of our gradebooks.

No miracles, but progress!