Struct WalStorageManager 

pub struct WalStorageManager { /* private fields */ }

WAL-integrated storage manager

Coordinates writes between WAL and memtable for ACID compliance.

Implementations

impl WalStorageManager

pub fn new<P: AsRef<Path>, F>(wal_path: P, apply_fn: F) -> Result<Self>

where F: Fn(&[u8], &[u8]) -> Result<()> + Send + Sync + 'static,

Create a new WAL storage manager

pub fn begin_txn(&self) -> Result<u64>

Begin a new transaction

pub fn write(&self, txn_id: u64, key: Vec<u8>, value: Vec<u8>) -> Result<()>

Write within a transaction (buffered)

The write is buffered until commit. This allows rollback.

pub fn write_immediate( &self, txn_id: u64, key: Vec<u8>, value: Vec<u8>, ) -> Result<()>

Write immediately to WAL (for single-statement transactions)

This is more efficient for simple writes that don’t need buffering.

pub fn commit(&self, txn_id: u64) -> Result<u64>

Commit a transaction

1. Write all buffered writes to WAL
2. fsync WAL for durability
3. Apply writes to memtable
4. Remove transaction from active set

pub fn abort(&self, txn_id: u64) -> Result<()>

Abort a transaction

Discards all buffered writes.

pub fn recover(&self) -> Result<RecoveryStats>

Recover from WAL after crash

Replays committed transactions and applies them to storage.

pub fn checkpoint(&self) -> Result<()>

Checkpoint: truncate WAL after flush

Called after memtable flush to SST. Safe to discard WAL entries.

pub fn wal(&self) -> &Arc<TxnWal>

Get WAL reference

pub fn current_timestamp(&self) -> u64

Get current timestamp