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jcrodriguez-dis / moodle-mod_vpl

Virtual Programming Lab for Moodle (Module)
GNU General Public License v3.0
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Error reading from database #59

Open eric-sh-wei opened 6 years ago

eric-sh-wei commented 6 years ago

HI, I don't know if it just me. When I click on "Submissions list", I get "Error reading from database". Please advise me what I can do. I'm running moodle 3.4.1 with mod_vpl 3.3.2 Thank you

2018-01-14 11 07 54
jcrodriguez-dis commented 6 years ago

Hello Eric, to try to resolve your problem I need more information. Please, put your Moodle in debug mode to see the error details, replay the action that generate the error and report me what you get. To put your Moodle in debug mode go to Dashboard / ► Site administration / ► Development / ► Debugging and select imagen

Best regards, Juan Carlos.

eric-sh-wei commented 6 years ago

Hi Juan, Thank you for quick replying and your wonderful job that you have done. Here are the screen shots.

2018-02-05 11 21 48 2018-02-05 11 22 15 2018-02-05 11 22 27

jcrodriguez-dis commented 6 years ago

Hello Eric, I have tryed to replay the bug with no success. The problem come from the function "get_users_by_capability" of the Moodle API. This function, based on capabilities, is used in VPL to get the users that can submit works. No other people has reported this problem then it may be related with your installation or an error in your DB. Please, if you have more information related with the users, users’ capabilities of the buggy activity, show it. This may help to replay the problem.

Best regards, Juan Carlos.

mad1989 commented 2 years ago

Hello Juan Carlos, Hello Eric, We had the same problem. In our case, the error only occurs when a large number of students (>80) log on to Moodle at the same time. In VPL, the problem is primarily limited to the login procedure or the beginning of the exam, while in VPL Question the problem occurs permanently during the exam situation. According to our admins, the main reason for this is that our Moodle instance was not originally designed for this use.

Best regards, Dominik

jcrodriguez-dis commented 2 years ago

Hello Dominik. Please, adjunct the message that Moodle shows to try to identify the problem. Please also detail the versions of the software you are using. O.S., Moodle, VPL, VPL Question.

If your Moodle message is identical to Eric's message, please check that your users use an appropriate role. If you are using custom roles check the VPL assigned capabilities follow the assigned in the standard roles.

mod/vpl:addinstance mod/vpl:grade mod/vpl:manage mod/vpl:setjails mod/vpl:similarity mod/vpl:submit mod/vpl:view

Best regards.