Struct LeaderState 

pub struct LeaderState {
    pub next_index: HashMap<NodeId, LogIndex>,
    pub match_index: HashMap<NodeId, LogIndex>,
}

Volatile state on leaders (reinitialized after election)

Fields

next_index: HashMap<NodeId, LogIndex>

For each server, index of the next log entry to send to that server

match_index: HashMap<NodeId, LogIndex>

For each server, index of highest log entry known to be replicated on server

Implementations

impl LeaderState

pub fn new(peers: &[NodeId], last_log_index: LogIndex) -> Self

Create a new leader state

pub fn update_success(&mut self, peer: NodeId, match_idx: LogIndex)

Update next_index for a peer after successful replication

pub fn update_failure(&mut self, peer: NodeId)

Update next_index for a peer after failed replication

pub fn update_failure_with_hint( &mut self, peer: NodeId, conflict_index: Option<LogIndex>, _conflict_term: Option<Term>, follower_last_index: LogIndex, )

Update next_index for a peer after failed replication using conflict hints.

This implements the “fast backup” optimization from the Raft paper: instead of decrementing next_index one at a time, we jump back to the conflict point reported by the follower.

• conflict_index: the first index of the conflicting term on the follower
• conflict_term: the term of the conflicting entry
• follower_last_index: the follower’s last log index

If the leader has entries with conflict_term, it sets next_index to the index after its last entry of that term. Otherwise, it sets next_index to conflict_index.

pub fn calculate_commit_index_joint( &self, leader_id: NodeId, current_last_index: LogIndex, config_state: &ConfigState, ) -> LogIndex

Calculate the commit index considering joint consensus.

During joint consensus, an entry must be replicated to a majority of both the old and new configurations. The leader itself counts toward both configs.

pub fn get_next_index(&self, peer: NodeId) -> LogIndex

Get next_index for a peer

pub fn get_match_index(&self, peer: NodeId) -> LogIndex

Get match_index for a peer

pub fn calculate_commit_index( &self, current_index: LogIndex, quorum_size: usize, ) -> LogIndex

Calculate the commit index based on match_index values Returns the highest index that is replicated on a majority of servers

Trait Implementations

impl Clone for LeaderState

fn clone(&self) -> LeaderState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LeaderState

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

Formats the value using the given formatter.