know t k returns true iff the key is present in the memory table or the disk.
Return value if it is found in-memory, or else on disk. Otherwise fail with error
inject t k v returns
k is already present in the memory table or in the disk, or has already been requested. Otherwise it updates the memory table and return
val fetch : t -> ?peer:Tezos_base.TzPervasives.P2p_peer.Id.t -> ?timeout:Tezos_base.TzPervasives.Time.System.Span.t -> key -> param -> value Tezos_base.TzPervasives.tzresult Lwt.t
fetch t ?peer ?timeout k param returns the value when it is known. It can fail with
Timeout k if
timeout is provided and the value isn't know before the timeout expires. It can fail with
Cancel if the request is canceled.
The key is first looked up in memory, then on disk. If not present and not already requested, it schedules a request, and blocks until the requester is notified with
param is used to validate the notified value once it is received. (see also
Requests are re-sent via a 1.5 exponential back-off, with initial delay set to
Request.initial_delay. If the function is called multiple time with the same key but with distinct peers, the internal scheduler randomly chooses the requested peer (at each retry).