v.25.3New Feature

Add concurrent_threads_scheduler server

Official CH changelog text
Added concurrent_threads_scheduler server setting that governs how CPU slots are distributed among concurrent queries. Could be set to round_robin (previous behavior) or fair_round_robin to address the issue of unfair CPU distribution between INSERTs and SELECTs. #75949 (Sergei Trifonov).
Introduces the concurrent_threads_scheduler server setting to control CPU slot allocation among concurrent queries in ClickHouse.

Why it matters

This feature solves the issue of unfair CPU distribution between INSERT and SELECT queries by allowing users to choose a scheduling algorithm that balances CPU resources more fairly.

How to use it

Set the concurrent_threads_scheduler server setting to either round_robin (default behavior) or fair_round_robin to enable fairer CPU slot distribution among concurrent queries.

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