Run GET _cat/thread_pool?v&h=node_name,name,max,pool_size,size,type,queue_size
Gives you details on Elasticsearch threadpool size, type, queue_size.
Example output
node_name name max pool_size size type queue_size
instance-0000000009 analyze 0 1 fixed 16
instance-0000000009 ccr 32 32 fixed 100
instance-0000000009 fetch_shard_started 4 0 scaling -1
instance-0000000009 fetch_shard_store 4 0 scaling -1
instance-0000000009 flush 1 0 scaling -1
instance-0000000009 force_merge 0 1 fixed -1
instance-0000000009 generic 128 4 scaling -1
instance-0000000009 get 0 2 fixed 1000
instance-0000000009 listener 0 1 fixed -1
instance-0000000009 management 5 3 scaling -1
instance-0000000009 ml_datafeed 512 0 scaling -1
instance-0000000009 ml_job_comms 2048 0 scaling -1
instance-0000000009 ml_utility 2048 1 scaling -1
instance-0000000009 refresh 1 0 scaling -1
instance-0000000009 rollup_indexing 0 4 fixed 4
instance-0000000009 search 0 4 fixed_auto_queue_size 1000
instance-0000000009 search_throttled 0 1 fixed_auto_queue_size 100
instance-0000000009 searchable_snapshots_cache_fetch_async 28 0 scaling -1
instance-0000000009 searchable_snapshots_cache_prewarming 16 0 scaling -1
instance-0000000009 security-crypto 0 1 fixed 1000
instance-0000000009 security-token-key 0 1 fixed 1000
instance-0000000009 snapshot 1 0 scaling -1
instance-0000000009 system_read 0 1 fixed 2000
instance-0000000009 system_write 0 1 fixed 1000
instance-0000000009 transform_indexing 0 4 fixed 4
instance-0000000009 warmer 1 0 scaling -1
instance-0000000009 watcher 0 1 fixed 1000
instance-0000000009 write 0 2 fixed 10000
instance-0000000006 analyze 0 1 fixed 16
instance-0000000006 ccr 32 32 fixed 100
instance-0000000006 fetch_shard_started 4 0 scaling -1
instance-0000000006 fetch_shard_store 4 1 scaling -1
instance-0000000006 flush 1 1 scaling -1
instance-0000000006 force_merge 1 1 fixed -1
instance-0000000006 generic 128 128 scaling -1
instance-0000000006 get 2 2 fixed 1000
instance-0000000006 listener 0 1 fixed -1
instance-0000000006 management 5 5 scaling -1
instance-0000000006 ml_datafeed 512 0 scaling -1
instance-0000000006 ml_job_comms 2048 0 scaling -1
instance-0000000006 ml_utility 2048 2 scaling -1
instance-0000000006 refresh 1 1 scaling -1
instance-0000000006 rollup_indexing 0 4 fixed 4
instance-0000000006 search 4 4 fixed_auto_queue_size 1000
instance-0000000006 search_throttled 0 1 fixed_auto_queue_size 100
instance-0000000006 searchable_snapshots_cache_fetch_async 28 0 scaling -1
instance-0000000006 searchable_snapshots_cache_prewarming 16 0 scaling -1
instance-0000000006 security-crypto 1 1 fixed 1000
instance-0000000006 security-token-key 0 1 fixed 1000
instance-0000000006 snapshot 1 1 scaling -1
instance-0000000006 system_read 1 1 fixed 2000
instance-0000000006 system_write 1 1 fixed 1000
instance-0000000006 transform_indexing 0 4 fixed 4
instance-0000000006 warmer 1 1 scaling -1
instance-0000000006 watcher 10 10 fixed 1000
instance-0000000006 write 2 2 fixed 10000
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