The queries that did not hit the cache and need recursion service take up space in the requestlist. If there are too many queries, first queries get overwritten, and at last resort dropped.
|Average size of queue on insert||t_ql_avg||gauge|
|Max size of queue (in 5 min)||t_ql_max||gauge|
|Number of queries replaced by new ones||t_ql_overwritten||gauge|
|Number of queries dropped due to lack of space||t_ql_exceeded||gauge|