Statistics

Cache<Key, Graph> graphs = Caffeine.newBuilder()
    .maximumSize(10_000)
    .recordStats()
    .build();

By using Caffeine.recordStats(), you can turn on statistics collection. The Cache.stats() method returns a CacheStats which provides statistics such as

• hitRate(): returns the ratio of hits to requests
• evictionCount(): the number of cache evictions
• averageLoadPenalty(): the average time spent loading new values

These statistics are critical in cache tuning and we advise keeping an eye on these statistics in performance-critical applications.

The cache statistics can be integrated with a reporting system using either a pull or push based approach. A pull-based approach periodically calls Cache.stats() and records the difference since the last snapshot. A push-based approach supplies a custom StatsCounter so that the metrics are updated directly during the cache operations.

See stats-metrics for a simple example using Dropwizard Metrics.