Details
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Type:
Bug
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Status: Closed
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Priority:
Minor
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Resolution: Fixed
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Affects Version/s: 2.6.2
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Testing Instructions:
- Upgrade your site and verify that there are no errors.
- Try to view the plugin overview page, and verify there are no errors.
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Affected Branches:MOODLE_26_STABLE
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Fixed Branches:MOODLE_26_STABLE, MOODLE_27_STABLE
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Pull from Repository:
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Pull Master Branch:
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Pull Master Diff URL:
Description
When loading the plug-in overview page, I am seeing queries like:
SELECT 'x' FROM mdl_question_attempts WHERE behaviour = 'missing' LIMIT 0, 1
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It looks like it runs for every possible behaviour. When the question_attempts table is large, this can take a long time, causing extremely long load times on the plug-in overview page.Why do these queries run when you load that page and can we put an index on that field?
explain SELECT 'x' FROM mdl_question_attempts WHERE behaviour = 'missing' LIMIT 0, 1;
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+------+-------------+-----------------------+------+---------------+------+---------+------+---------+-------------+
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| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
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+------+-------------+-----------------------+------+---------------+------+---------+------+---------+-------------+
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| 1 | SIMPLE | mdl_question_attempts | ALL | NULL | NULL | NULL | NULL | 3317019 | Using where |
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+------+-------------+-----------------------+------+---------------+------+---------+------+---------+-------------+
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SELECT 'x' FROM mdl_question_attempts WHERE behaviour = 'manualgraded' limit 0, 1;
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Empty set (1 min 29.28 sec)
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Attachments
Issue Links
- caused a regression
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- Closed
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