https://useinov.com/tags/monitoring/ Recent content in Monitoring on Murat Useinov Hugo en-us Tue, 04 Aug 2020 20:40:00 +0300 https://useinov.com/posts/2020/average-explains-nothing/ Tue, 04 Aug 2020 20:40:00 +0300 https://useinov.com/posts/2020/average-explains-nothing/ <p>Average response time: 180 ms. Ticket from support: &ldquo;the API is slow&rdquo;. Both true. The average is a diplomat. It offends nobody and tells you nothing.</p> <p>Latency is a distribution. Our 180 ms hides a p50 of 90 ms and a p99 above four seconds. One request in a hundred is terrible, and with thirty requests per page load, most users hit that unlucky one regularly. The people complaining are not imagining things. They live in the tail, and the average never visits there.</p>