If you are still on 3.x, treat 4.x as the line you should plan to run. Log stream APIs and OBProxy pooling behavior in 4.x are the interfaces most current tooling expects. Schedule the upgrade against your next change window rather than waiting for an emergency.

Upgrade highlights

  • Unified log stream API replaces legacy partition leader views.
  • Improved EXPLAIN ANALYZE output for distributed plans.
  • OCP 4.x required for combined dashboard metrics.

Action items

Audit custom SQL against __all_virtual_* views. Several were renamed in the 4.x transition. Update Grafana dashboards before your next on-call rotation.