Struct VersionedLog 

pub struct VersionedLog { /* private fields */ }

A transaction log split into per-lease-version files for HA append isolation (see docs/design/log-and-transactor.md).

The active writer under lease version V appends only to {name}.v{V}.log (the pre-HA {name}.log reads as version 0). Readers merge the files in version order and drop any record in an older file whose t is at or past the first record of a later file: such records were appended by a deposed writer after a takeover and were never acknowledged, because acknowledgement re-verifies lease ownership after the durable append. A deposed writer therefore cannot corrupt or fork the log — its stale appends land in a file nobody considers current.

Implementations

impl VersionedLog

pub fn open( dir: impl AsRef<Path>, name: &str, write_version: u64, ) -> Result<Self, LogError>

Opens the log for writing under write_version, creating the version file if needed and dropping any torn tail it carries. Files of other versions are never modified.

Errors

Returns an error if files cannot be read/created or a fully written record is corrupt.

pub fn open_read_only( dir: impl AsRef<Path>, name: &str, ) -> Result<Self, LogError>

Opens the log read-only (offline inspection, backup); appends fail.

Errors

Returns an error when the directory cannot be read or a fully written record is corrupt.

pub fn exists(dir: impl AsRef<Path>, name: &str) -> bool

Reports whether any log file exists for this database.

pub fn delete_all(dir: impl AsRef<Path>, name: &str) -> Result<(), LogError>

Deletes every version file for this database.

Errors

Returns an error when a file cannot be removed.

Trait Implementations

impl TransactionLog for VersionedLog

fn append(&self, record: &TxRecord) -> Result<(), LogError>

Durably appends exactly the next transaction.

fn tx_range( &self, start: u64, end: Option<u64>, ) -> Result<Vec<TxRecord>, LogError>

Returns records in the half-open transaction range [start, end).

fn append_async<'life0, 'life1, 'async_trait>( &'life0 self, record: &'life1 TxRecord, ) -> Pin<Box<dyn Future<Output = Result<(), LogError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Durably appends exactly the next transaction without blocking an async runtime worker. Synchronous logs use Self::append by default; storage-backed logs override this method and await their backend.

fn tx_range_async<'life0, 'async_trait>( &'life0 self, start: u64, end: Option<u64>, ) -> Pin<Box<dyn Future<Output = Result<Vec<TxRecord>, LogError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Asynchronous form of Self::tx_range.

fn replay(&self) -> Result<Vec<TxRecord>, LogError>

Replays every committed record.

fn replay_async<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Vec<TxRecord>, LogError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Asynchronously replays every committed record.