Articles by tag: query-log

MV in ClickHouse: data loss and control

Analysis of risks of materialized views in ClickHouse: schema errors, block insert, monitoring system.query_views_log. How to avoid losses in production. Practical code examples.

CPU 80% Diagnostics in ClickHouse

Tools for finding problematic queries in ClickHouse: system.processes, query_log, EXPLAIN. Diagnostics steps, SQL examples, checklist. Optimize load without downtime.