es_threadpool_tasks_number is always empty

[Kuckkuck]

The metric es_threadpool_tasks_number is always empty on all nodes. Any idea, what has to be activated to enable this metric? It's always 0 on data, master and client nodes.

I am using Elastic: 7.9.2. with the 7.9.2.0 elastic prometheus exporter plugin.

[yashumitsu]

It seems it shows only queued tasks in threadpool:

• https://github.com/vvanholl/elasticsearch-prometheus-exporter/blob/7.14.1.0/src/main/java/org/compuscene/metrics/prometheus/PrometheusMetricsCollector.java#L621

To see currently running threads, we use query: es_threadpool_threads_number{type="active"}.