Struct Wal 

pub struct Wal { /* private fields */ }

Write-Ahead Log implementation.

Provides durable logging for database transactions with configurable sync policies and automatic segment rotation.

Implementations

impl Wal

pub fn open(dir: &Path, config: WalConfig) -> Result<Self>

Opens or creates a WAL in the given directory.

If the directory contains existing WAL segments, they will be opened for append. Otherwise, a new segment is created.

pub fn append(&mut self, record: &WalRecord) -> Result<Lsn>

Appends a record to the WAL.

Returns the LSN of the appended record.

pub fn sync(&mut self) -> Result<()>

Explicitly syncs the WAL to disk.

pub fn current_lsn(&self) -> Lsn

Returns the current LSN (next write position).

pub fn truncate_before(&mut self, lsn: Lsn) -> Result<()>

Truncates WAL segments before the given LSN.

This is called after a checkpoint to reclaim space.

pub fn replay<F>(&self, from_lsn: Lsn, callback: F) -> Result<Lsn>

where F: FnMut(WalRecord) -> Result<()>,

Replays records from the given LSN.

The callback is invoked for each record in LSN order. Returns the final LSN after replay.

pub fn approximate_size(&self) -> u64

Returns total bytes written across all segments (approximate WAL size).