Enum SyncMode 

pub enum SyncMode {
    Full,
    Normal,
    Off,
}

Durability mode for FileHandle::sync_data.

SyncMode is the user-visible knob that selects the cross-platform fsync primitive obj calls after a WAL commit. The contract for each variant is documented in docs/format.md § SyncMode.

The default is SyncMode::Full: a commit that returns Ok(()) is durable across a system-wide power loss. Normal is the throughput-tuned middle ground; Off skips the syscall and is only safe for tests and benchmarks.

Power-of-ten Rule 5: a three-state enum is far cheaper to audit than three bool knobs, and the variants are exhaustive at every match.

Variants

Full

Strongest durability. Survives system-wide power loss.

Maps to fcntl(F_FULLFSYNC) on macOS (forces the drive cache to flush), FlushFileBuffers on Windows, and fdatasync on Linux / BSDs. macOS’s plain fsync is not sufficient here — it does not flush the drive cache; F_FULLFSYNC does. This is the standard wisdom for safety-critical macOS storage.

Normal

Process-crash and kernel-panic durability; may lose data on a sudden power loss if the drive’s write cache has not been flushed by the time the OS acknowledges the call.

Maps to fsync on Unix and FlushFileBuffers on Windows. On Windows there is no weaker primitive than FlushFileBuffers, so Normal and Full are equivalent there.

Off

No durability call. The OS may write the data eventually, but obj does not ask it to. Use only for tests and benchmarks where data loss is acceptable.

Trait Implementations

impl Clone for SyncMode

fn clone(&self) -> SyncMode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SyncMode

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

Formats the value using the given formatter.

impl Default for SyncMode

fn default() -> SyncMode

Returns the “default value” for a type.

impl PartialEq for SyncMode

fn eq(&self, other: &SyncMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for SyncMode

impl Eq for SyncMode

impl StructuralPartialEq for SyncMode