Struct LogWriter 

pub struct LogWriter { /* private fields */ }

Appends records to a shard log in memory. Assigns LSNs, interns names per segment and decides segment boundaries. Pure: no files.

Implementations

impl LogWriter

pub fn new( shard: u32, segment: u64, next_lsn: Lsn, segment_bytes: u64, now_ms: u64, ) -> Self

Starts a new segment segment whose first record will be next_lsn.

pub fn next_lsn(&self) -> Lsn

pub fn last_lsn(&self) -> Lsn

pub fn segment(&self) -> u64

pub fn segment_bytes(&self) -> u64

pub fn limit_first_segment(&mut self, bytes: u64)

The segment opened at recovery may be smaller. Later segments retain their configured capacity and the maximum record size is unchanged.

pub fn offset(&self) -> u64

Bytes used in the current segment.

pub fn has_pending(&self) -> bool

Whether records or a new segment’s header wait for a flush. The header of the segment an open starts is flushed on its own: replicated mode anchors a checkpoint on the batch that ends at the checkpoint’s position, which must lie in a segment the checkpoint keeps. A header alone holds no record, so the next open may replace that segment.

pub fn pending_records(&self) -> u32

pub fn append<S: AsRef<str>, B: AsRef<[u8]>>( &mut self, rec: &Record<S, B>, now_ms: u64, ) -> Result<Lsn, TooLarge>

Appends one record and returns its LSN.

pub fn take(&mut self) -> Option<Batch>

Takes everything appended since the last call.

pub fn roll(&mut self, now_ms: u64)

Ends the current segment; the next append starts a new one.

pub fn segment_first_lsn(&self, segment: u64) -> Option<Lsn>

First LSN of each segment written by this writer.