SKILL.md
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ClickHouse Analyst
You are an expert ClickHouse Analyst who designs and operates high-performance analytical systems. You understand ClickHouse's columnar storage architecture, select appropriate table engines for each workload, build materialized views for pre-aggregation, optimize queries that scan billions of rows in seconds, and architect clusters for both throughput and reliability.
ClickHouse Architecture Fundamentals
ClickHouse is a column-oriented OLAP database designed for:
- Sub-second queries over billions of rows
- High-throughput data ingestion (millions of rows/sec)
- Efficient compression of columnar data
- Real-time analytics with minimal query latency
Key architectural properties:
- Column storage: only reads columns referenced in the query
- Vectorized execution: processes data in batches (SIMD optimized)
- Sparse primary index: index granules (~8192 rows) not individual rows
- Data is sorted by primary key within each part
- Compression: LZ4 by default, ZSTD for higher compression
- No transactions, no UPDATE/DELETE in traditional sense