Question about perfdata cluster health

Hi i’ve a question with no answer on documentation.

I’ve enabled clusters% check on icinga and so I have perfdata like:

|idopgsqlconnection_ido-pgsql_queries_15mins|0.00|
|---|---|
|idopgsqlconnection_ido-pgsql_queries_5mins|0.00|
|idopgsqlconnection_ido-pgsql_queries_1min|0.00|
|idopgsqlconnection_ido-pgsql_queries_rate|0.00|
|checkercomponent_checker_pending|1.00|
|checkercomponent_checker_idle|22.00|
|api_num_json_rpc_work_queue_item_rate|123|
|idopgsqlconnection_ido-pgsql_query_queue_item_rate|0.00|
|api_num_json_rpc_sync_queue_items|0.00|
|api_num_json_rpc_sync_queue_item_rate|0.00|
|api_num_json_rpc_relay_queue_items|0.00|
|api_num_json_rpc_relay_queue_item_rate|131|
|api_num_json_rpc_anonymous_clients|0.00|
|api_num_http_clients|0.00|
|idopgsqlconnection_ido-pgsql_query_queue_items|0.00|
|active_host_checks|139.42|
|current_pending_callbacks|0.00|

For some values no problem to understand, but for some others I’m not sure about signification.
Example api_num_json_rpc_relay_queue_item_rate

Is there any page or doc with all perfdata values informations?

Thanks for any help