Two new counters have been added to serverStatus() output. Named: metrics.query.planning.fastPath.idHack and metrics.query.planning.fastPath.express that count the number of queries that used either fastPath strategy when being planned.

Description of Linked Ticket

We used to count the number of idhack operations, but this was removed in SERVER-23272. Under this ticket, we should consider re-introducing a counter for the number of idhack operations (probably incorporating idhack find, delete, and update commands into one metric). We may also wish to have a separate counter for the number of non-idhack queries which are answered using the new PlanExecutorExpress fast path.