Cache invalidation via CDC

Design a cache-invalidation system driven by change-data-capture for a read-heavy product catalog: a multi-region edge cache serves ~2M reads/sec, the source of truth is a primary database, and a price or availability change must invalidate/refresh the relevant cached entries everywhere within a couple seconds. Requirements: no entry stays stale indefinitely, an invalidation storm (bulk price update on 1M SKUs) must not stampede the database, and regions must converge. Walk through capture, propagation, and the failure modes.