Struct segments::MemoryLog

pub struct MemoryLog<T> { /* fields omitted */ }

Log is an inmemory commitlog (per topic) which splits data in segments. It drops the oldest segment when retention policies are crossed. Each segment is identified by base offset and a new segment is created when ever current segment crosses disk limit

Implementations

impl<T: Debug + Clone> MemoryLog<T>

pub fn new(max_segment_size: usize, max_segments: usize) -> MemoryLog<T>

Create a new log

pub fn head_and_tail(&self) -> (u64, u64)

pub fn append(&mut self, size: usize, record: T) -> (u64, u64)

Appends this record to the tail and returns the offset of this append. When the current segment is full, this also create a new segment and writes the record to it. This function also handles retention by removing head segment

pub fn next_offset(&self) -> (u64, u64)

pub fn read(&mut self, cursor: (u64, u64)) -> Option<T>

Read a record from correct segment

pub fn readv(
    &mut self,
    cursor: (u64, u64),
    out: &mut Vec<T>
) -> Option<(u64, u64)>

Reads multiple packets from the disk and returns base offset and offset of the next log. When data of deleted segment is asked, returns data of the current head Note: segment id is used to be able to pull directly from correct segment Note: This method also returns full segment data when requested data is not of active segment. Set your max_segment size keeping tail latencies of all the concurrent connections mind (some runtimes support internal preemption using await points)

Trait Implementations

impl<T: Debug> Debug for MemoryLog<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.