Struct LocalOptions 

pub struct LocalOptions {
    pub flush: FlushMethod,
    pub direct_io: bool,
    pub preallocate: Preallocate,
    pub segment_bytes: u64,
    pub flusher_spin: Duration,
    pub emulated_flush: Duration,
    pub prepare_bytes_per_sec: u64,
}

Fields

flush: FlushMethod

direct_io: bool

Linux only (default there): open segments with O_DIRECT and write aligned 4 KiB blocks. The last partial block is kept in memory and written again, with the same bytes, by the next write. If the filesystem refuses O_DIRECT with EINVAL, at an open or at a write (ramfs, tmpfs before Linux 6.6, devices whose blocks are larger than 4 KiB), that log directory falls back to buffered writes, and FlushMethod::Dsync to fdatasync, for the life of the process; one line on stderr says so. Not used with FlushMethod::IoUring or by a replica’s [BatchWriter]. The shared log (crate::wal) applies the same option with its own probe.

preallocate: Preallocate

segment_bytes: u64

flusher_spin: Duration

How long the flusher thread spins for new work before sleeping. Spinning trades a busy core for lower handoff latency under moderate load.

emulated_flush: Duration

Adds this much to every flush (benchmarks that emulate slower disks).

prepare_bytes_per_sec: u64

Pace of background zero-filling of successor segments, so preparing one does not take the device away from the logs. Ignored once a log is waiting for the segment.

Trait Implementations

impl Clone for LocalOptions

fn clone(&self) -> LocalOptions

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LocalOptions

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

Formats the value using the given formatter.

impl Default for LocalOptions

fn default() -> Self

Returns the “default value” for a type.