How to Analyze ClickHouse Query Plan Contention

High-contention queries in ClickHouse can cause unexpected row locks, serializing write throughput despite available IOPS. This is a resource starvation issue caused by lock granularity, not a CPU issue. To diagnose, monitor system.query_log and system.trace_log for queries exceeding expected execution times or locking resources. Use SELECT * FROM system.events WHERE event = 'QueryQueue' to visualize queue depth and wait states in real-time. Correlate database metrics with infrastructure load balancer logs to confirm if contention is internal or network-induced.