Cycle Analytics: first iteration
## What does this MR do?
- Implement the first iteration of the "Cycle Analytics" feature.
## What are the relevant issue numbers?
- Closes#21170
## Screenshots
![cycle_analytics_screencast.gif](/uploads/d23c3c912caa6935fd47b53ca3a56b97/cycle_analytics.gif)
## Backend Tasks
- [x] Implementation
- [x] Phases
- [x] Issue (Tracker)
- [x] Plan (Board)
- [x] Code (IDE)
- [x] Test (CI)
- [x] Review (MR)
- [x] Staging (CD)
- [x] Production (Total)
- [x] Make heuristics more modular
- [x] Scope to project
- [x] Date range (30 days, 90 days)
- [x] Access restriction
- [x] Test
- [x] Find a better way to test these phases
- [x] Phases
- [x] Issue (Tracker)
- [x] Plan (Board)
- [x] Code (IDE)
- [x] Test (CI)
- [x] Review (MR)
- [x] Staging (CD)
- [x] Production (Total)
- [x] Test for "end case happens before start case"
- [x] Consolidate helper
- [x] Miniboss review
- [x] Performance testing with mock data
- [x] Improve performance
- [x] Pre-calculate "merge requests closing issues
- [x] Pre-calculate everything else
- [x] Test performance against 10k issues
- [x] Test all pre-calculation code
- [x] Ci::Pipeline -> build start/finish
- [x] Ci::Pipeline#merge_requests
- [x] Issue -> record default metrics after save
- [x] MergeRequest -> record default metrics after save
- [x] Deployment -> Update "first_deployed_to_production_at" for MR metrics
- [x] Git Push -> Update "first commit mention" for issue metrics
- [x] Merge request create/update/refresh -> Update "merge requests closing issues"
- [x] Remove `MergeRequestsClosingIssues` when necessary
- [x] Changes to unblock Fatih
- [x] Add summary data
- [x] `stats` should be array
- [x] Let `stats` be `null` if all `stats` are null
- [x] Indexes for "merge requests closing issues"
- [x] Test summary data
- [x] Scope everything to project
- [x] Find out why tests were passing
- [x] Filter should include issues/MRs which have made it to production within the range
- [x] Don't create duplicate `MergeRequestsClosingIssues`
- [x] Fix tests
- [x] MySQL median
- [x] Assign to Douwe for review
- [x] Fix conflicts
- [x] Implement suggestions from Yorick's review
- [x] Test on PG
- [x] Test on MySQL
- [x] Refactor
- [x] Cleanup
- [x] What happens if we have no data at all?
- [x] Extract common queries to methods / scopes
- [x] Remove unused queries
- [x] Downtime for foreign key migrations
- [x] Find a way around "if issue.metrics.present?" all over the place
- [x] Find a way around "if merge_request.metrics.present?" all over the place
- [x] Test migrations on a fresh database
- [x] MySQL
- [x] Pg
- [x] Access issues
- While the project is public and the visibility is set to "Everyone with access", you cannot visit the cycle analytics page when signed out.
- [x] CHANGELOG
- [x] Implement suggestions from Douwe's review
- [x] First set of comments
- [x] Second set of comments
- [x] Third set of comments
- [x] Fourth set of comments
- [x] Make sure build is green
- [ ] Make issue for "polish"
- [ ] EE MR
See merge request !5986