Cache hit ratio.

also: hit ratio · hit rate · cache hit rate · cache hit · cache hits · cache miss · cache misses

The share of requests served from the cache: hits ÷ (hits + misses). Higher means less load on the source.

the two-minute refresher

Hit: found in the cache. Miss: fetched from the source (and usually cached).
At a 95% hit ratio the database sees only 5% of reads.
Skewed (Zipfian) traffic makes small caches effective.
A cold cache after a restart or deploy starts at 0%: warm it before peak traffic.

also: hit ratio · hit rate · cache hit rate · cache hit · cache hits · cache miss · cache misses

The share of requests served from the cache: hits ÷ (hits + misses). Higher means less load on the source.

Hit: found in the cache. Miss: fetched from the source (and usually cached).
At a 95% hit ratio the database sees only 5% of reads.
Skewed (Zipfian) traffic makes small caches effective.
A cold cache after a restart or deploy starts at 0%: warm it before peak traffic.