Document and review current ClickHouse uses/capabilities and future use cases
## Summary
This is an exit criteria of the ~"WorkingGroup::ClickHouse".
Exit criteria DRI: @marshall007
### Working Group Links
- [Meeting Agenda](https://docs.google.com/document/d/1ZZ7fE7s18Yxww9wp0-lO7mFxJmwop3pWvqINCQPNubA/edit#heading=h.rsbmdhwckvta)
- [Handbook Page](https://about.gitlab.com/company/team/structure/working-groups/clickhouse-datastore)
- [Slack Channel](https://gitlab.slack.com/archives/C04D13QHUH1)
### Use Cases
| Stage | Source | Use Cases | Current Solution |
| -------------------- | ------| ------ | ----- |
| ~"devops::monitor" | https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1200798270 | Error Tracking, Logs, Tracing, Metrics | Clickhouse |
| ~"devops::plan" | https://gitlab.com/groups/gitlab-org/-/epics/7964 https://gitlab.com/groups/gitlab-org/-/epics/9281 https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1203339711 | DORA4 metrics, Value Stream analytics, DevOps adoption metrics, Events (powers activity feeds and calendar) | Postgres, JSON reports generated periodically |
| ~"devops::analytics" | https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1202030574 https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1201695976 | User Tracking, Session Recording, A/B testing, Customer Surveys, dogfooding for ~"group::product intelligence", [Service Ping](https://docs.gitlab.com/ee/development/service_ping/), SaaS Product Intelligence events collection | Clickhouse (WIP), PostgreSQL, Redis, Snowplow |
| ~"devops::configure" | https://gitlab.com/groups/gitlab-org/-/epics/2493 | Kubernetes monitoring (logs, events, metrics), Infrastructure Inventory & Cost Optimization | |
| ~"devops::modelops" | [POC](https://www.youtube.com/watch?v=A8Q6pNKNirQ) | Arbitrary data ingestion and exploration (like BigQuery), Monitoring/optimization of analytic workloads | Clickhouse |
| ~"devops::verify" | https://gitlab.com/gitlab-org/gitlab/-/issues/387672#note_1244770162 https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1201234824 | CI/CD analytics, pipeline statistics, historical test data, runner logs, monitoring/optimization of runner fleet | Postgres, Redis, Object Storage |
| ~"devops::create" | | Repository analytics, contribution statistics, code review analytics, monitoring of remote development environments | Postgres (?) |
| ~"devops::secure" | https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1202024852 | Security Dashboards, Vulnerability Lists, Add historical views to existing features | Postgres |
| ~"devops::govern" | https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1202538603 | Audit events | Postgres |
| ~"devops::package" | https://gitlab.com/gitlab-org/gitlab/-/issues/384184#note_1203143330 | Indexing package and container image metadata | Postgres |
| ~"group::delivery" | https://gitlab.com/gitlab-com/gl-infra/delivery/-/issues/2936 | Auto deploy events visualization | Prometheus |
| ~"group::runner" | https://gitlab.com/gitlab-org/gitlab/-/issues/390921 | Runner Fleet Management | None |
| ~"DE Infra/Reliability" | https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24361 | Package download requests via packages.gitlab.com | MySQL |
epic