The next course used was BerkeleyX/CS.CS169.1x/3T2013 (783 threads, 3385 comments at the time). Unlike the loadtest with the very large course "BerkeleyX/ColWri2.2x/1T2014", the server was able to handle the requests without returning 500s. These numbers seem more reasonable. The test ran for 1 hour.

As the loadtest continued, the 95th and 50th percentile gradually became slower and slower. The throughput was very high compared to that of production (~100rpm for a similar call /django_comment_client.forum.views:single_thread) so the test will be rerun with less load.

After analyzing this data, it was realized that the number of posts in this course had actually altered the response times of the http requests. The course had increased about 2-3 times. In a week, about 20,000 threads, 20,000 responses, and 10,000 comments are created in ALL COURSES. In this 1 hour test, we have created a fifth of that value against a single course. Take note that the following tests were against the same course, but with the new increased post count.

The test below was against the same course but at half the throughput. As shown on the graph, the response times were slower. This test ran for 30 minutes. Again, we see that the response times increases slowly as the RPMs decreases appropriately.

This is before adding the "asc" index and after adding the "last_activity_at" index. The major difference is the lack of spikes, consistent RPM, better response times especially for the large course and no 500s.

This test was run for 3 minutes with a small course vs large course on a 20:1 ratio. The large course used is BerkeleyX/ColWri2.2x/1T2014 (~38,000 threads, ~40,000 comments) , while the small course is SMES/ASLCx/1T2015 (1700 Threads, 3047 comments).