Struct sled::LockFreeLog

pub struct LockFreeLog { /* fields omitted */ }

A sequential store which allows users to create reservations placed at known log offsets, used for writing persistent data structures that need to know where to find persisted bits in the future.

Working with LockFreeLog

use sled::Log;

let log = sled::Config::default().log();
let first_offset = log.write(b"1".to_vec());
log.write(b"22".to_vec());
log.write(b"333".to_vec());

// stick an abort in the middle, which should not be returned
let res = log.reserve(b"never_gonna_hit_disk".to_vec());
res.abort();

log.write(b"4444".to_vec());
let last_offset = log.write(b"55555".to_vec());
log.make_stable(last_offset);
let mut iter = log.iter_from(first_offset);
assert_eq!(iter.next().unwrap().1, b"1".to_vec());
assert_eq!(iter.next().unwrap().1, b"22".to_vec());
assert_eq!(iter.next().unwrap().1, b"333".to_vec());
assert_eq!(iter.next().unwrap().1, b"4444".to_vec());
assert_eq!(iter.next().unwrap().1, b"55555".to_vec());
assert_eq!(iter.next(), None);

Methods

impl LockFreeLog

fn start_system(config: Config) -> LockFreeLog

create new lock-free log

fn flush(&self)

Flush the next io buffer.

fn defer_hole_punch(&self, lids: Vec<u64>)

Clean up log entries for data that may not yet be on the disk yet.

Trait Implementations

impl Send for LockFreeLog

impl Sync for LockFreeLog

impl Drop for LockFreeLog

fn drop(&mut self)

Executes the destructor for this type.

impl Log for LockFreeLog

fn reserve(&self, buf: Vec<u8>) -> Reservation

Create a log offset reservation for a particular write, which may later be filled or canceled.

fn config(&self) -> &Config

return the config in use for this log

fn write(&self, buf: Vec<u8>) -> u64

Write a buffer to underlying storage.

fn read(&self, id: u64) -> Result<LogRead>

read a buffer from the disk

fn stable_offset(&self) -> u64

returns the current stable offset written to disk

fn make_stable(&self, id: u64)

blocks until the specified id has been made stable on disk

fn punch_hole(&self, id: u64) -> Result<()>

deallocates the data part of a log id

fn iter_from(&self, id: u64) -> LogIter<Self>

Return an iterator over the log, starting with a specified offset.