Struct LsmIndex 

pub struct LsmIndex { /* private fields */ }

LSM-tiered streaming vector index.

Provides O(1) amortized inserts with multi-level search across independently-built HNSW graphs.

Implementations

impl LsmIndex

pub fn new(config: LsmConfig) -> Self

Create a new LSM-tiered index.

pub fn insert(&mut self, doc_id: u32, vector: Vec<f32>) -> Result<()>

Insert a vector.

Appends to L0. When L0 exceeds buffer_capacity, triggers compaction.

pub fn insert_slice(&mut self, doc_id: u32, vector: &[f32]) -> Result<()>

Insert from a borrowed slice.

pub fn delete(&mut self, doc_id: u32)

Mark a vector for deletion.

pub fn search(&self, query: &[f32], k: usize) -> Result<Vec<(u32, f32)>>

Search across all levels, merging results.

Searches each level independently, filters tombstones, and merges by distance. Cost: O(L * search_per_level) where L = number of levels.

pub fn compact(&mut self) -> Result<()>

Trigger compaction: merge L0 into L1, and cascade if needed.

Compaction builds an HNSW graph from the merged vectors and replaces the target level. Tombstoned vectors are excluded during the merge.

pub fn len(&self) -> usize

Number of active (non-tombstoned) vectors across all levels.

pub fn is_empty(&self) -> bool

Whether the index has no active vectors.

pub fn num_levels(&self) -> usize

Number of levels (including L0).

pub fn level_sizes(&self) -> Vec<usize>

Number of vectors at each level.

pub fn stats(&self) -> LsmStats

Statistics.

pub fn force_merge_all(&mut self) -> Result<()>

Force-compact all levels into a single bottom level.

Useful for read-heavy workloads: eliminates multi-level search overhead. Expensive: rebuilds the entire graph.