Struct WalWriter 

pub struct WalWriter { /* private fields */ }

Append-only WAL writer.

Implementations

impl WalWriter

pub fn open(path: &Path, config: WalWriterConfig) -> Result<Self>

Open or create a WAL file at the given path.

pub fn set_encryption_key(&mut self, key: WalEncryptionKey)

Set the encryption key. When set, all subsequent records will have their payloads encrypted with AES-256-GCM.

pub fn set_encryption_ring(&mut self, ring: KeyRing)

Set the key ring directly (for key rotation with dual-key reads).

pub fn encryption_ring(&self) -> Option<&KeyRing>

Access the key ring (for decryption during replay).

pub fn open_with_start_lsn( path: &Path, config: WalWriterConfig, start_lsn: u64, ) -> Result<Self>

Open a new WAL segment file with a specific starting LSN.

Used by SegmentedWal when rolling to a new segment. The file must not already exist (or be empty). The writer will assign LSNs starting from start_lsn.

pub fn open_without_direct_io(path: &Path) -> Result<Self>

Open a WAL writer with O_DIRECT disabled (for testing on tmpfs, etc.).

pub fn append( &mut self, record_type: u16, tenant_id: u32, vshard_id: u16, payload: &[u8], ) -> Result<u64>

Append a record to the WAL. Returns the assigned LSN.

The record is written to the in-memory buffer. Call sync() to flush to disk and make the write durable.

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

Flush the write buffer to disk (group commit).

This issues a single write + fsync for all records accumulated since the last flush. The DWB is also fsynced (one fsync for all deferred DWB writes in this batch).

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

Seal the WAL — no more writes will be accepted.

Flushes any buffered data before sealing.

pub fn next_lsn(&self) -> u64

The next LSN that will be assigned.

pub fn file_offset(&self) -> u64

Current file size (bytes written to disk).