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KQMATH / moodle-mod_capquiz

:mushroom: Computer adaptive practice activity module for Moodle
https://moodle.org/plugins/mod_capquiz
GNU General Public License v3.0
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Postgres reports error #166

Closed hgeorgsch closed 4 years ago

hgeorgsch commented 5 years ago

On the production server, we see a large number of similar errors in the log: 2019-10-28 20:41:41.837 MET [25736] moodleuser@moodle ERROR: duplicate key value violates unique constraint "mdl_quesatte_queslo_uix" 2019-10-28 20:41:41.837 MET [25736] moodleuser@moodle DETAIL: Key (questionusageid, slot)=(1722, 3227) already exists. 2019-10-28 20:41:41.837 MET [25736] moodleuser@moodle STATEMENT: INSERT INTO mdl_question_attempts (questionusageid,slot,behaviour,questionid,variant,maxmark,minfraction,maxfraction,flagged,questionsummary,rightanswer,responsesummary,timemodified) VALUES($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13) RETURNING id

Most of the activity is using CAPQuiz, and the server is reacting slow at the moment. The error seems to be an inconsistency in the database contents, and makes a plausible cause. Does anyone understand enough of the database to identify the underlying problem and/or correct the inconsistency?

hgeorgsch commented 5 years ago

By the way, this may or may not be related to #165

hgeorgsch commented 5 years ago

Checking some instances, there seems to be no inconsistency in the database, so the ERROR, presumably, indicates an INSERT operation being rejected. Thus we need to debug in moodle, and find out where and why this happens.

hgeorgsch commented 4 years ago

This is probably due to overloading the database, an issue which has been resolved in Moodle 3.9