Struct LazyFlatVectorData 

pub struct LazyFlatVectorData {
    pub dim: usize,
    pub num_vectors: usize,
    pub doc_ids: Vec<(u32, u16)>,
    /* private fields */
}

Lazy flat vector data — doc_ids in memory, vectors accessed via range reads.

Only the doc_id index (~6 bytes/vector) is loaded into memory. Vector data (~dim×4 bytes/vector) stays on disk and is accessed via mmap-backed range reads on demand. For 768-dim vectors this is ~3KB per vector that stays lazy vs 6 bytes loaded.

Used for:

• Reranking (read individual vectors by doc_id)
• Merge streaming (bulk-read vector bytes in chunks)

Fields

dim: usize

Vector dimension

num_vectors: usize

Total number of vectors

doc_ids: Vec<(u32, u16)>

In-memory doc_id index: (doc_id, ordinal) per vector

Implementations

impl LazyFlatVectorData

pub async fn open(handle: LazyFileSlice) -> Result<Self>

Open from a lazy file slice pointing to the flat binary data region.

Reads header (12 bytes) + doc_ids (~6 bytes/vector) into memory. Vector data stays lazy on disk.

pub async fn read_vector_into(&self, idx: usize, out: &mut [f32]) -> Result<()>

Read a single vector by index into a caller-provided slice (zero allocation).

out must have length >= self.dim. Returns Ok(()) on success.

pub async fn get_vector(&self, idx: usize) -> Result<Vec<f32>>

Read a single vector by index (allocates a new Vec).

pub async fn read_all_vector_bytes(&self) -> Result<OwnedBytes>

Read all raw vector bytes at once (for bulk streaming in merger).

Returns the contiguous f32 data as owned bytes. Caller writes it directly to the output writer — no f32 parsing needed.

pub fn get_doc_id(&self, idx: usize) -> (u32, u16)

Get doc_id and ordinal at index (from in-memory index).

pub fn estimated_memory_bytes(&self) -> usize

Estimated memory usage (only doc_ids are in memory).

Trait Implementations

impl Clone for LazyFlatVectorData

fn clone(&self) -> LazyFlatVectorData

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LazyFlatVectorData

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

Formats the value using the given formatter.