Struct Wal 

pub struct Wal { /* private fields */ }

Group-commit WAL writer. Append is O(buffer copy) and never fsyncs; callers (or a timer) drive Wal::sync.

Implementations

impl Wal

pub fn create(path: impl AsRef<Path>, epoch_created: Epoch) -> Result<Self>

Create a new WAL segment, truncating any existing file at path.

pub fn create_with_cipher( path: impl AsRef<Path>, epoch_created: Epoch, cipher: Option<Box<dyn Cipher>>, segment_no: u64, ) -> Result<Self>

Create a new WAL segment with optional frame-level encryption. The persisted segment_no namespaces AES-GCM nonces across segments under the constant WAL DEK (spec §7.1, review fix #23).

pub fn append_txn(&mut self, txn_id: u64, op: Op) -> Result<Epoch>

Append a record belonging to transaction txn_id. Assigns the next monotonic sequence (the first record after a WAL created at E gets E + 1), writes it, and returns the assigned sequence. Does NOT fsync — call Wal::sync (or rely on the byte threshold). The WAL sequence is independent of the row commit epoch; the engine tracks commit epochs separately.

pub fn append_system(&mut self, op: Op) -> Result<Epoch>

Append a system record (txn_id == SYSTEM_TXN_ID), e.g. Flush.

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

Flush the buffer and fsync the file. This is the durability point.

pub fn unflushed_bytes(&self) -> u64

Pending bytes not yet fsynced.

pub fn next_seq_val(&self) -> u64

The next sequence number this writer will assign (i.e. last assigned + 1). Exposed so a shared-WAL group-sync can report the durable high-water mark.

pub fn set_sync_byte_threshold(&mut self, threshold: u64)

Tune the auto-sync threshold (bytes of buffered WAL before an automatic fsync). 0 disables auto-sync entirely (manual Wal::sync only) — useful for latency benchmarks and for grouping many writes under one explicit commit.

pub fn path(&self) -> &Path

Trait Implementations

impl Drop for Wal

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.