Struct ValueLog 

pub struct ValueLog { /* private fields */ }

Value log for storing large values

Implementations

impl ValueLog

pub fn new(vlog_dir: impl AsRef<Path>) -> Result<Self>

Create a new value log with default configuration

pub fn with_config(config: ValueLogConfig) -> Result<Self>

Create a new value log with custom configuration

pub fn with_config_and_gc( config: ValueLogConfig, gc_config: GcConfig, ) -> Result<Self>

Create a new value log with custom configuration and GC configuration

pub fn should_separate(&self, value: &CipherBlob) -> bool

Check if a value should be stored in vLog

pub fn append(&self, key: Key, value: CipherBlob) -> Result<ValuePointer>

Append a value to the vLog and return a pointer

pub fn read(&self, pointer: &ValuePointer) -> Result<CipherBlob>

Read a value from the vLog using a pointer

pub fn flush(&self) -> Result<()>

Flush buffered writes

pub fn current_file_id(&self) -> u64

Get current file ID

pub fn config(&self) -> &ValueLogConfig

Get configuration

pub fn last_write_time_millis(&self) -> u64

Get the timestamp (millis since UNIX epoch) of the last write operation

pub fn time_since_last_write(&self) -> Duration

Get the duration since the last write operation

impl ValueLog

GC-related methods for ValueLog

pub fn mark_dead(&self, pointer: &ValuePointer)

Mark a value as dead/stale in segment stats

This should be called when a key is overwritten or deleted, invalidating the old value in the vLog.

pub fn dead_ratio(&self, file_id: u64) -> f64

Get the dead ratio for a given segment (file_id)

Returns dead_bytes / total_bytes, or 0.0 if the segment has no data.

pub fn segment_stats(&self, file_id: u64) -> Option<SegmentStats>

Get a copy of the segment stats for a given file_id

pub fn is_gc_running(&self) -> bool

Check if GC is currently running

pub fn total_reclaimable_bytes(&self) -> u64

Get total reclaimable bytes across all segments

pub fn collect_garbage<F>(&self, is_live_fn: F) -> Result<GcResult>

where F: Fn(&Key) -> bool,

Collect garbage across all eligible segments

Finds segments exceeding the dead ratio threshold and old enough, then rewrites live entries to new segments and deletes old ones.

is_live_fn: Function that checks if a key is still live in the LSM-Tree. The function receives the key and should return true if the key’s current value pointer still points to this entry.

pub fn reclaim_segment<F>( &self, file_id: u64, is_live_fn: &F, ) -> Result<(u64, u64)>

where F: Fn(&Key) -> bool,

Reclaim a single segment by rewriting live entries to the active segment

Returns (bytes_reclaimed, entries_rewritten) on success.

pub fn garbage_collect_file<F>( &self, file_id: u64, is_live_fn: F, ) -> Result<GcStats>

where F: Fn(&Key) -> bool,

Perform garbage collection on a vLog file

Scans the file and rewrites live values to a new file, discarding dead values. This is typically called when a file has too much garbage.

is_live_fn: Function that checks if a key is still live in the LSM-Tree

pub fn calculate_garbage_ratio<F>( &self, file_id: u64, is_live_fn: F, ) -> Result<f64>

where F: Fn(&Key) -> bool,

Calculate garbage ratio for a vLog file

Returns the ratio of dead values to total values. This can be used to determine if GC is needed.