## Context In https://gitlab.com/gitlab-org/gitlab/-/issues/523857, we identified the top 2 slowest endpoints owned by ~"group::code review" which and causied the most apdex budget consumption. 1. `GET /api/:version/projects/:id/merge_requests` 2. `GET /api/:version/groups/:id/merge_requests` This is confirmed to still be the case as of last week: https://gitlab.com/gitlab-com/create-stage/weekly-status-check-in/-/issues/110#note_2593833499 ## Goal 1. Investigate impact of the current performance (e.g. percentiles of duration for above-target queries, # of namespaces/users impacted, etc) 1. Investigate ways to improve the performance of the endpoints ## Kibana Dashboard https://log.gprd.gitlab.net/app/r/s/tkljo This dashboard includes the following data: - Total slow requests (broken down by project/group API endpoints) - Total slow requests with search (broken down by project/group API endpoints) - Unique count of slow requests by root namespace - Unique count of slow requests by UA - Top 10 root namespaces - Top 10 UA - Top 10 users - Request rate of top 5 root namespaces - This shows total request rate for the 2 endpoints including non-slow ones. - Duration of slow project list MRs API requests (median, P75, P95, P99) - Duration of slow group list MRs API requests (median, P75, P95, P99) - Time spent on each component - This shows median time spent on DB, redis, gitaly, and view. - One caveat with `view_duration_s` is that it can include time spent not on actual rendering but method calls that were called during serialization of the entity