I'm trying to view a submission to an assignments folder, but instead of showing me the document, D2L displayed the message, "This document is rendering slowly." What's going on?
D2L shows the "This document is rendering slowly" message for a given assignments submission when all three of these circumstances come together:
- No one has viewed that particular assignments submission before.
- D2L has not pre-processed that particular assignments submission.
- The assignments submission is unusually large or complex.
- Many other course instructors are currently viewing submissions to their own assignments folders.
Before assignments can display a submission, D2L must first convert the submitted document to Portable Document Format (PDF). The conversion happens behind the scenes, and only has to happen one time per assignments submission, because D2L's document converter, called the document builder service, maintains a cache of converted assignments submissions.
D2L's document builder service can only convert a certain number of documents simultaneously. When a large number of course instructors, at Millersville and at other PASSHE schools, all try to view assignments submissions at the same time, the document conversion requests those instructors create are put into a queue, one that the document builder service works through in a first come, first served manner.
During busy times, such as near the close of academic terms, the document builder service's queue can grow long, and so unfortunately, during those times, you'll stand a higher chance of encountering the "rendering slowly" message.
Additionally, larger and more complex documents take longer to convert, so they can trigger the "rendering slowly" message all on their own—and when a queue has formed, such documents can further delay conversion. This impacts all instructors, PASSHE-wide.
For more on file size limits in dropbox, please see: Assignments size limits
To try to save you from suffering the "rendering slowly" message, D2L also run the document builder service automatically, on a regular schedule, to pre-process and cache assignment submissions that haven't been converted and viewed previously.