Struct WalManager 

pub struct WalManager { /* private fields */ }

Manages the Write-Ahead Log with rotation, checkpointing, and durability modes.

Implementations

impl WalManager

pub fn open(dir: impl AsRef<Path>) -> Result<Self>

Opens or creates a WAL in the given directory.

Errors

Returns an error if the directory cannot be created or accessed.

pub fn with_config(dir: impl AsRef<Path>, config: WalConfig) -> Result<Self>

Opens or creates a WAL with custom configuration.

Errors

Returns an error if the directory cannot be created or accessed.

pub fn log(&self, record: &WalRecord) -> Result<()>

Logs a record to the WAL.

Errors

Returns an error if the record cannot be written.

pub fn checkpoint( &self, current_transaction: TransactionId, epoch: EpochId, ) -> Result<()>

Writes a checkpoint marker and persists checkpoint metadata.

The checkpoint metadata is written atomically to a separate file, allowing recovery to skip WAL files that precede the checkpoint.

Errors

Returns an error if the checkpoint cannot be written.

pub fn read_checkpoint_metadata(&self) -> Result<Option<CheckpointMetadata>>

Reads checkpoint metadata from disk.

Returns None if no checkpoint metadata exists.

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

Rotates to a new log file.

Errors

Returns an error if rotation fails.

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

Flushes the WAL buffer to disk.

Errors

Returns an error if the flush fails.

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

Syncs the WAL to disk (fsync).

Errors

Returns an error if the sync fails.

pub fn record_count(&self) -> u64

Returns the total number of records written.

pub fn dir(&self) -> &Path

Returns the WAL directory path.

pub fn durability_mode(&self) -> DurabilityMode

Returns the current durability mode.

pub fn log_files(&self) -> Result<Vec<PathBuf>>

Returns all WAL log file paths in sequence order.

pub fn checkpoint_epoch(&self) -> Option<EpochId>

Returns the latest checkpoint epoch, if any.

pub fn size_bytes(&self) -> usize

Returns the total size of all WAL files in bytes.

pub fn last_checkpoint_timestamp(&self) -> Option<u64>

Returns the timestamp of the last checkpoint (Unix epoch seconds), if any.

pub fn close_active_log(&self)

Closes the active log file, releasing its file handle.

This allows the WAL directory to be safely removed on Windows, where open file handles prevent directory deletion. A new log file will be created automatically on the next write.

impl WalManager

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

Opens a single WAL file (legacy API).

Errors

Returns an error if the file cannot be opened.

pub fn path(&self) -> PathBuf

Returns the path to the active WAL file.