kafka.request.handler_idle_percent

When Kafka request handlers are saturated (low idle percentage), producer requests queue up, increasing end-to-end latency and potentially triggering producer-side timeouts.

When request queue size grows, it indicates the broker cannot process incoming requests fast enough, leading to increased latency and potential client timeouts.

When consumer fetch latency increases significantly, it indicates the broker is slow to respond to fetch requests, often due to disk I/O, CPU saturation, or competing produce traffic.