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In this series of tests, we will be testing against different sized courses with different ratios. There are spikes in response times in production and one possibility may be that the few very large courses may be the reason. In this initial test, we ran it for 3 hours, with a small course vs large course on a 20:1 ratio. The large course used is BerkeleyX/ColWri2.2x/1T2014 (~25,000 threads, 30,000 comments) , while the small course is SMES/ASLCx/1T2015 (1700 Threads, 3047 comments). We can see that there are spikes in the response times. There have been many 500 responses from the large course so for the next test, the data will be refreshedwhich needs to be addressed. There were many unexpected 500 errors during this test. Upon further investigation, it was found that there was a memory issue due to missing indexes.
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The chart below is the SMES/ASLCx/1T2015 (1700 Threads, 3047 comments) loadtest by itself for reference. These numbers are not comparable since the test in the chart below was at 10 users vs 20 users in the above test.
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Addressing the 500s:
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Although only present on the larger courses, a significant amount of 500s were being returned. A solution has been proposed to include an index to account for this but for now in order to continue the load tests, the offending parameters "last_activity_at" and "asc" will be removed from out random selection. This also means that our thread retrieval for PATCHing (and DELETEing which has been disabled) will be less random, but sufficiently random. By removing these parameters, we hope to get rid of these 500s and see a performance improvement for large and small courses.
Test reruns:
NEXT STEPS:
Address the 500s
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