[LON-CAPA-admin] LON-CAPA & Placement testing

[Guy Albertelli II]

Hi Jeff,

> We are planning to use LON-CAPA to do some placement testing in 
> mathematics for incoming students. My question is in regard to processing 
> course statistics and charts for large numbers of students and the 
> potential this may have for increased load on the server and possible 
> performance issues. We are running two servers (1 library / 1 access).
> 
> There will be approximately 1500-2000 students who eventually take the 
> placement test (essentially this number of students is enrolled in a 
> single L-C course). I'm wondering about what the conventional wisdom is 
> out there for running stat reports to obtain grades for 1500+ students at 
> once? 

We've had probalby around 20ish classes in the 1000-2000 student range
here at MSU.

Time spent computing is pretty much linear with regards to number of
problems and students in the course.

Checking a couple of example courses at MSU
- 1866 students, 38 problems took 17 minutes to generate the CHRT
   Excel spreadsheet
- 2148 students, 102 problems (133 parts), took around 45 minutes to
   generate the CHRT Excel spreadsheet 

> We've never run this number of students before and are curious about 
> processing time to generate reports...any thoughts? Also, what impact 
> might the frequent running of these report have on performance?

The system tries to cache any unchanging information to speed
generation of the reports.

Generally with the situation you are asking about here (placement
exam) most students do the work once and never interact again. Correct?

The data is cached on a per student basis and thus only new student
data will need to be fetched and analyzed.

Thus more frequent runnings should generally be faster than infrequent
runnings (data is usualy cached for no less than 24 and nor more than
48 hours from the last time it was needed)

-- 
guy at albertelli.com   0-7-1-8-27,137