FINAL in ClickHouse Isn’t as Expensive as It Used to Be

Short summary

ClickHouse's FINAL operator was historically expensive to avoid, but modern versions with parallel execution and partition optimizations make it significantly more practical. The key is understanding your workload: FINAL is reasonable for latest-state queries on small partitions but remains expensive on massive scans. Rather than blanket avoidance or blind application, focus on whether the tradeoff suits your specific operational needs.

• •Modern ClickHouse has improved FINAL through parallel execution and partition-aware optimizations, reversing historical performance penalties
• •FINAL is now acceptable for latest-state queries with controlled partition sizes, not universally avoided as in older guidance
• •Understand why your query needs FINAL and whether the computational tradeoff is acceptable for your workload before deciding

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