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- Selecting threads from a smaller pool or selecting the same thread. Rather than getting the entire list of thread_ids to send requests against, we would just store a random portion of the threads. A test was run to see if matters whether the retrieved thread was random or not, but the sandbox it was run against did not have the correct mongo indexes set up. Regardless, this strategy would not work when trying to DELETE threads as the pool of potential threads would be smaller. Additionally this relies on storing data that must be shared amongst the locust users which could lead to race conditions as a locust user could be trying to GET a thread that another locust user was in the middle of DELETEing. When dealing with much larger file IO operations, it could cause some limitations on the machine that spawns the locusts.
- Retrieving the list of thread ids when starting locust. This method was effective up until the number of threads in the data set started to increase. As the median number of posts in a course is ~2000, when trying to retrieve 20*(page size max of 100), it would take 20 queries. Additionally, as mentioned in the above strategy, storing data amongst the locust users is not a trivial task. Each locust user would try to generate it's own list of threads which is unacceptable. If a thread was POSTed or DELETEd, only that locust user would have that updated information. Attempts at using the lazy module did not work either as each list of threads was instantiated separately by each locust user. Again, even if the locust users were able to use the same global variables, there would be race conditions.
Calling GET thread_list per DELETE/PATCH/GET_comment. Since the ratio of GET thread_list is significantly higher than any of the other calls, we can achieve the desired distribution of requests for the discussion API.
The table below is a 7 day snapshot on NewRelic for the
Action Count Discussion API Call .forum.views:single_thread 675980 4760 GET Thread .forum.views:forum_form_discussion 234783 1653 GET Thread List .forum.views:inline_discussion 155176 1093 GET Thread List create_thread 31176 220 POST Thread create_comment 27438 193 POST comment create_sub_comment 14345 101 POST comment users 13820 97 - .forum.views:user_profile 12336 87 - .forum.views:followed_threads 7698 54 GET Thread List vote_for_comment 6731 47 PATCH Comment vote_for_thread 6242 44 PATCH Thread upload 4208 30 - update_comment 3403 24 PATCH Comment follow_thread 3870 27 PATCH Thread update_thread 2827 20 PATCH Thread delete_thread 2091 15 DELETE Thread endorse_comment 1232 9 PATCH Comment delete_comment 770 5 DELETE Comment flag_abuse_for_comment 373 3 PATCH Comment flag_abuse_for_thread 142 1 PATCH Thread - Using pre-stored thread_id data.
Things that were left out:
Moderator actions
- Pin Thread - Not implemented
- Open/Close Thread -Not implemented
- Endorsed - Not Implemented
Staff vs. Normal User:
Using users with staff access was thrown into consideration as it would be make some of the permissions a bit more difficult for some discussion forums actions such as editing the body of a thread. Some tests were ran to see if there was a difference. No difference was found the tests that were designed to check for a difference.
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