Many complaints about sluggish events calendar performance. After considerable analysis, the bottleneck was www.uvm.edu . Talks with SAA suggested Network File System (NFS) performance as culprit, as was how the CodeIgnitor MVC (model-view-controller) framework used the file system.
Case in point: I had a CodeIgnitor “View” (a single php file) that displayed details of one event. The default calendar view displays maybe 70 events, past and present. So, application loops through all the events, invoking the Single Event View 70 times. That incurred 70 file reads from a sluggish NFS file share. SSllllloooowww.
So I recast the 1-event-view as a function call. 1-event view loads function once, invokes function once. N-event-view loads function once, invokes function N times. Fast.
While I was at it, I optimized some of the SQL queries by adding additional indexes to database tables.