How to Optimize a Redis Big Key Online Without Disrupting Existing Services (Interview Answer)
The article explains what a Redis big key is, why it harms performance, typical scenarios that generate big keys, and provides a step‑by‑step online optimization plan—including key sharding, dual‑write synchronization, progressive migration with HSCAN, gray‑scale traffic switch, non‑blocking deletion using UNLINK, and monitoring with rollback procedures—to answer the interview question confidently.
