Caching Operations (ElastiCache/DAX)
Explore how to manage caching with ElastiCache and DAX effectively. Understand cache hit and miss behavior, diagnose cache-related latency and errors, and implement safe remediation steps to maintain database performance and availability in AWS environments.
Placing a cache in front of a data store splits every request onto one of two paths, and each path is governed by a different set of signals. A cache hit terminates at the cache, so cache latency and cache errors shape what the user experiences. A cache miss continues to the database, so database connections and database latency take over, with the cache adding only pass-through overhead. The two paths can produce very similar symptoms on the surface, which is exactly what makes cache incidents easy to misdiagnose as database incidents.
This matters most when a workload turns miss-heavy. Rising 5xx errors and p95 latency climbing from tens of milliseconds to multiple seconds can look database-shaped on the surface, even when Amazon RDS CPU and storage latency stay normal and steady. If cache hit rate is dropping and cache memory pressure signals are climbing in that same window, the cache layer can dominate both latency and errors even while the database itself is healthy. Confirming hit rate direction before treating RDS as the primary failure domain is what keeps that misread from ... ...