Struct ReadProbe 

pub struct ReadProbe {
    pub term: Term,
    pub leader: NodeId,
    pub seq: u64,
}

A leader’s read-confirmation probe, the network half of a linearizable read.

To serve a read that reflects every previously-committed write, a leader must confirm it is still the leader at the moment of the read — a deposed leader that has not yet learned of its fall could otherwise answer with stale state (the ReadIndex protocol, Raft thesis §6.4). The leader sends ReadProbe to every other voter and waits for a quorum of ReadProbeReplys carrying the matching seq before releasing the read. The probe carries no log data and changes no state; it is a pure leadership check.

Examples

use raft_io::ReadProbe;

let probe = ReadProbe { term: 5, leader: 1, seq: 42 };
assert_eq!(probe.seq, 42);

Fields

term: Term

The leader’s term.

leader: NodeId

The leader issuing the probe.

seq: u64

A monotonic confirmation-round number, echoed back in the reply so the leader can tell which round a reply confirms.

Trait Implementations

impl Clone for ReadProbe

fn clone(&self) -> ReadProbe

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReadProbe

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deserialize for ReadProbe

fn deserialize<__D: Decode + ?Sized>(__decoder: &mut __D) -> Result<Self>

Read a value of Self from the decoder, advancing its cursor.

fn deserialize_many<D>( decoder: &mut D, count: usize, ) -> Result<Vec<Self>, SerialError>

where D: Decode + ?Sized,

Read count consecutive Self values into a freshly-allocated Vec.

impl Eq for ReadProbe

impl PartialEq for ReadProbe

fn eq(&self, other: &ReadProbe) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ReadProbe

fn serialize<__E: Encode + ?Sized>(&self, __encoder: &mut __E) -> Result<()>

Append the encoded bytes of self to encoder.

fn serialize_slice<E>( slice: &[Self], encoder: &mut E, ) -> Result<(), SerialError>

where E: Encode + ?Sized, Self: Sized,

Append the encoded bytes of every element of slice to encoder.

impl StructuralPartialEq for ReadProbe