cache-observability

Track cache hit rates, latency, and detect cache-related issues

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/development/cache-observability-nexus-labs-automatio-backend-observabilit

SKILL.md

Cache Observability

Cache is performance-critical. Track hit rate, latency, and evictions.

Key Metrics

Metric	Type	Description
`cache.hits`	Counter	Successful reads
`cache.misses`	Counter	Reads that missed
`cache.gets.duration`	Histogram	GET latency
`cache.evictions`	Counter	Keys evicted
`cache.memory.used`	Gauge	Memory consumption

Span Attributes

Attribute	Example	Required
`cache.system`	redis, memcached	Yes
`cache.operation`	GET, SET	Yes
`cache.hit`	true/false	Yes
`cache.key_prefix`	user:*	Recommended (not full key!)

Hit Rate

hit_rate = cache.hits / (cache.hits + cache.misses)

Good: >90%
Concerning: <80% → Check TTL, warming strategy

Issues to Detect

Issue	Detection	Fix
Low hit rate	<80%	Tune TTL, warm cache
Cache stampede	Many misses for same key	Distributed locks
High latency	p99 >10ms	Check network, value size
Memory pressure	memory >90% of max	Eviction policy, sizing

Cache Wrapper Pattern

Before GET: Start timer
After GET:  Record duration, increment hits or misses, set cache.hit on span

Anti-Patterns

Full keys in metrics → High cardinality, use prefix only
No eviction monitoring → Can't detect memory pressure
Ignoring serialization time → Track total time including marshal

References

references/platforms/{platform}/cache.md