v.25.7New Feature

Workload setting max_waiting_queries is now supported

The workload setting max_waiting_queries is now supported. It can be used to limit the size of the query queue. If the limit is reached, all subsequent queries will be terminated with the SERVER_OVERLOADED error. #81250 (Oleg Doronin).
The workload setting max_waiting_queries has been introduced to limit the size of the query queue in ClickHouse.

Why it matters

This feature helps prevent excessive query queue buildup by terminating new queries with a SERVER_OVERLOADED error once the queue size reaches the specified limit. It ensures better resource management and system stability under high load.

How to use it

To use this feature, set the max_waiting_queries parameter in the workload configuration to the desired maximum number of queued queries. When the number of waiting queries exceeds this limit, new queries will be rejected immediately with a SERVER_OVERLOADED error.