This is the approach we took while building our Internal Developer Platform: watches (via client-go informers with client-side caching) to sync data into a Postgres database as JSONB. Changes are tracked using JSON patches and Kubernetes events. To avoid a watch on every resource kind, we handle this by performing incremental object fetches for the objects involved in watched events.

Getting this to perform well required several optimizations at both the Go and Postgres levels. On the Go side, we use prioritized work queues, event de-duplication, and even switched to Rust for efficient JSON diffs. For Postgres, we leverage materialized views and trigger-based optimistic locking