Struct CompactConfig 

pub struct CompactConfig {
    pub max_space_amplification_percent: u16,
    pub min_bottom_merge_bytes: u64,
    pub max_files_above_bottom: usize,
    pub size_ratio_percent: u16,
    pub rewrite_per_fresh_byte: f32,
    pub max_merge_jobs: usize,
}

Configuration for the compaction algorithm.

Fields

max_space_amplification_percent: u16

A shard is merged into a new bottom run when the files above its bottom run are larger than this percentage of the bottom run. E.g. 50 merges a shard with a 100MB bottom run once more than 50MB are above it. 0 merges every shard that has files above its bottom run.

min_bottom_merge_bytes: u64

A shard is only merged into a new bottom run when at least this many bytes are above its bottom run. This is to avoid tiny families that always rewrite everything doing constant full merges and starving other work.

max_files_above_bottom: usize

The files above the bottom run of a shard are merged when there are more than this many (at least one, since merging a single file would only move it).

size_ratio_percent: u16

An intermediate merge takes the newest file above the bottom run, and then each next older one that is at most this percentage larger than the files taken so far, but at least the two newest. E.g. with 100, a file joins while it’s at most twice the size of the newer files combined. This is the size ratio of RocksDB’s universal compaction.

rewrite_per_fresh_byte: f32

Bottom merges of a family are scheduled until they rewrote this many bytes per byte of its fresh files; the last one may go past it, and the first one always runs. E.g. with 3.0, after commits wrote 10MB to a family, no more bottom merges are scheduled once they rewrote 30MB, except for shards far behind.

max_merge_jobs: usize

The maximum number of merge jobs in a compaction, across all families. Merge jobs run in parallel, so this bounds the work of a compaction. It doesn’t limit the number of files merged by a job.

Implementations

impl CompactConfig

pub fn full() -> Self

A config that merges every shard with files above its bottom run into a new bottom run.

Trait Implementations

impl Clone for CompactConfig

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CompactConfig

impl Debug for CompactConfig

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

Formats the value using the given formatter.

impl Default for CompactConfig

fn default() -> Self

Returns the “default value” for a type.