PostgreSQLMetricredis.keyspace.hits
Number of successful lookups of keys in the main dictionarySummary
Cumulative counter of successful key lookups where the requested key existed in Redis. The cache hit rate (hits / (hits + misses)) is a primary indicator of cache effectiveness. Declining hit rates may indicate inadequate cache size causing excessive evictions, poor key distribution, or application logic changes. A well-tuned cache typically maintains >90% hit rate for read-heavy workloads.
Related Insights (3)
Event loop blocking creates false appearance of cache ineffectiveness - Redis cache hits are fast individually, but serial request processing prevents concurrent cache lookups from improving overall throughput during traffic bursts.
High Redis memory fragmentation ratio (>1.5) causes actual memory usage to exceed redis.memory.maxmemory limits, triggering premature key evictions and reducing cache hit rates even when logical memory usage appears healthy.
When redis.keys.evicted rate increases significantly, Redis is evicting keys to stay within maxmemory limits, potentially causing cache miss storms and degraded application performance as hot data is prematurely evicted.