clickhouse-query-optimization

SKILL.md

Search terms: query optimization, PREWHERE, JOIN, dictionary, EXPLAIN, performance, slow query, memory limit, timeout, full table scan, dictGet, query cache, DELETE, UPDATE, mutation, aggregation, GROUP BY, COUNT DISTINCT, uniq, querylog

The ORDER BY clause in table definition determines query performance. ClickHouse stores data sorted by these columns and uses a sparse primary index to skip irrelevant data.

Key insight: Always filter on the leftmost ORDER BY columns first for best performance.

Más de 20 reglas de optimización para consultas de ClickHouse. Cargue al escribir consultas, depurar consultas lentas, corregir errores de memoria u optimizar JOIN. Logra consultas entre 10 y 100 veces más rápidas y un 90 % menos de uso de memoria. Fuente: obsessiondb/clickhouse-skills.

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