Struct RedbLogStore 

pub struct RedbLogStore { /* private fields */ }

redb-backed Raft log storage

This is a pure Rust implementation that:

• Has zero C/C++ dependencies
• Compiles for any target (including musl)
• Provides ACID transactions
• Uses B-tree for efficient ordered access

Performance Characteristics

• Write: O(log n) per entry, batched for throughput
• Read: O(log n) point lookup, O(k) range scan for k entries
• Space: ~1.5x raw data size (B-tree overhead)

For Raft workloads (append-heavy with sequential reads), this provides excellent performance with the benefit of pure Rust simplicity.

Implementations

impl RedbLogStore

pub fn new(path: impl AsRef<Path>) -> Result<Self>

Create new redb log storage at the given path

Creates the directory if it doesn’t exist.

pub fn is_cache_stale(&self) -> bool

Check whether this instance’s cached metadata is still current.

Returns true when the shared write-version counter has advanced past the version observed at clone-time, indicating that the parent store has been mutated (vote, committed, purge, etc.). The primary store (snapshot_version == None) is always authoritative.

pub async fn refresh_cache_if_stale(&self)

Reload cached metadata (vote, last_purged, committed) from the database if the cache is stale. No-op on the primary store.

Trait Implementations

impl RaftLogReader<TypeConfig> for RedbLogStore

async fn try_get_log_entries<RB: RangeBounds<u64> + Clone + Debug + Send>( &mut self, range: RB, ) -> Result<Vec<RaftEntry>, StorageError<NodeId>>

Use a single read transaction with range iteration instead of opening a separate transaction per entry via get_log().

fn limited_get_log_entries( &mut self, start: u64, end: u64, ) -> impl Future<Output = Result<Vec<<C as RaftTypeConfig>::Entry>, StorageError<<C as RaftTypeConfig>::NodeId>>> + Send

Returns log entries within range [start, end), end is exclusive, potentially limited by implementation-defined constraints.

impl RaftLogStorage<TypeConfig> for RedbLogStore

type LogReader = RedbLogStore

Log reader type.

async fn get_log_state( &mut self, ) -> Result<LogState<TypeConfig>, StorageError<NodeId>>

Returns the last deleted log id and the last log id.

async fn get_log_reader(&mut self) -> Self::LogReader

Get the log reader.

async fn save_vote( &mut self, vote: &RaftVote, ) -> Result<(), StorageError<NodeId>>

Save vote to storage.

async fn read_vote(&mut self) -> Result<Option<RaftVote>, StorageError<NodeId>>

Return the last saved vote by Self::save_vote.

async fn save_committed( &mut self, committed: Option<RaftLogId>, ) -> Result<(), StorageError<NodeId>>

Saves the last committed log id to storage.

async fn read_committed( &mut self, ) -> Result<Option<RaftLogId>, StorageError<NodeId>>

Return the last saved committed log id by Self::save_committed.

async fn append<I>( &mut self, entries: I, callback: LogFlushed<TypeConfig>, ) -> Result<(), StorageError<NodeId>>

where I: IntoIterator<Item = RaftEntry> + Send, I::IntoIter: Send,

Append log entries and call the callback once logs are persisted on disk.

async fn truncate( &mut self, log_id: RaftLogId, ) -> Result<(), StorageError<NodeId>>

Truncate logs since log_id, inclusive

async fn purge(&mut self, log_id: RaftLogId) -> Result<(), StorageError<NodeId>>

Purge logs upto log_id, inclusive