Read-Through and Write-Through Caching: How Redis Handles Data Sync Automatically

Read-through and write-through are two Redis caching patterns that shift data-loading and write logic from the application into the cache layer itself. In read-through caching, the cache automatically fetches missing data from the database on a miss, centralising the loading logic rather than repeating it across the application. Write-through caching ensures that every write updates both the cache and the database synchronously, keeping them consistently in lockstep at the cost of higher write latency. Together, the two patterns let applications treat the cache as their primary data interface, eliminating scattered invalidation logic. However, the approach is best suited to read-heavy workloads where consistency is critical, and may be overkill for simpler use cases where cache-aside suffices.