altinity-expert-clickhouse-caches

Original：🇺🇸 English

Translated

Analyze ClickHouse cache systems including mark cache, uncompressed cache, and query cache. Use for cache hit ratio issues and cache tuning.

3installs

Added on2026-02-17

NPX Install

npx skill4agent add altinity/skills altinity-expert-clickhouse-caches

Analyze ClickHouse cache systems: mark cache, uncompressed cache, query cache, and compiled expression cache.

Run all queries from the file checks.sql and analyze the results.

Cache	Typical Size	Notes
Mark Cache	5-10% of RAM	Higher if random access patterns
Uncompressed	0 (disabled) or 5-10%	Enable only for specific workloads
Query Cache	1-5GB	For repeated identical queries
Compiled Expression	128MB-1GB	Higher for complex expressions

Possible causes:

If mark cache > 15% RAM:

Solutions:

Finding	Load Module	Reason
Cache using too much RAM	`altinity-expert-clickhouse-memory`	Overall memory analysis
Poor hit ratio + high disk IO	`altinity-expert-clickhouse-storage`	Disk bottleneck
Many marks per table	`altinity-expert-clickhouse-schema`	Consider index_granularity tuning
Query cache misses	`altinity-expert-clickhouse-reporting`	Query pattern analysis