Metrics.Unparented_blocks
val query : ( unit, int, [< `Many | `One | `Zero One ] ) Caqti_request.t
val update : (module Caqti_async.CONNECTION) -> Mina_metrics.Archive.t -> ( unit, [> Caqti_error.call_or_retrieve ] ) Core_kernel.Result.t Async_kernel__Deferred.t