dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
There are several improvements over what we had before:
1. We track all the questions seen in the the student's previous
quiz attempts, so that when they start a new quiz attempt, they get
questions they have not seen before if possible.
2. When there are no more unseen questions, we start repeating, but
always taking from the questions with the fewest attempts so far.
3. A similar logic is applied with variants within one question.
There is lots of credit to go around here. Oleg Sychev's students Alex
Shkarupa, Sergei Bastrykin and Darya Beda all worked on this over
several years, helping to clarify the problem and shape the best
solution. In the end, their various attempts were rewritten into this
final patch by me.
to question bank
- move cron to clean up old cache records move code and
rename classes
- further review of the quiz reports statistics code
- starting to separate calculations of quiz stats, question stats and
response analysis
- introduce hashcode db field for cached stats convert
- code to use qubaids hashcode for caches
We just drop the old tables (including previous upgrade steps) and
re-create the new ones, because these tables just cache calculated
statistics. No important data is stored in them.
This adds cron code which looks for question previews that have not been
touched for more than 24 hours, and deletes them.
We try to delete previews immediately. For example if the user clicks
start again, then we immediately delete their previous preview. However,
we can't do that if they just close the preview window. Hence we need
some cron code to clean up old preview that have got left lying around.
Normally, this code will not have much to do, so it will be very fast,
so we can afford to run it every cron.
This has been implemented in such a way that in future it will be easy
to add other cron code to the question bank.
Sadly, to make this work on MySQL, we require a horrible hack in the
already hacky delete_usage_records_for_mysql function.
MySQL only accepts 65536 (aprox) bytes in default TEXT
columns. So we define the max allowed as 32000 to allow
99.9% of utf-8 contents to fit. If some day MDL-19603 is
implemented and all current TEXTs are moved (MySQL) to
the BIG counterparts, this restriction can be out (MDL-19603).
1. So we will truncate the question summary to 65000 chars if necessary.
2. Also, fix one minor error in mutlianswer save_question_options.
question_bank::MAX_SUMMARY_LENGTH is not the most logical class to add
the constant to, but it needs to be accessible during upgrade, so I was
lazy and put it there.
While doing this, I found various bugs in the manages question types admin page, and so fixed them, and updated the code
there to use $OUTPUT and html_writer.
AMOS BEGIN
MOV [cannotdeletemissingqtype,admin],[cannotdeletemissingqtype,question]
MOV [cannotdeleteqtypeinuse,admin],[cannotdeleteqtypeinuse,question]
MOV [cannotdeleteqtypeneeded,admin],[cannotdeleteqtypeneeded,question]
MOV [deleteqtypeareyousure,admin],[deleteqtypeareyousure,question]
MOV [deleteqtypeareyousuremessage,admin],[deleteqtypeareyousuremessage,question]
MOV [deletingqtype,admin],[deletingqtype,question]
MOV [numquestions,admin],[numquestions,question]
MOV [numquestionsandhidden,admin],[numquestionsandhidden,question]
MOV [qtypedeletefiles,admin],[qtypedeletefiles,question]
MOV [uninstallqtype,admin],[uninstallqtype,question]
AMOS END
