use std::collections::{BTreeMap, BTreeSet};
use super::metric::{normalize_with_norm, MAX_HNSW_LEVEL};
use super::types::{HNSWGraphMeta, HNSWIndex, HNSWNode, HNSWNodeSnapshot};
use crate::vector_index::{validate_vector_values, HNSWIndexParams};
use crate::{StorageBackendError, StorageBackendResult};
impl HNSWIndex {
pub(crate) fn from_persistence(
dimensions: u32,
params: HNSWIndexParams,
meta: HNSWGraphMeta,
snapshots: Vec<HNSWNodeSnapshot>,
) -> StorageBackendResult<Self> {
let params = params.validate()?;
if meta.max_level > MAX_HNSW_LEVEL {
return Err(corrupt(&format!(
"metadata level {} exceeds the supported maximum {MAX_HNSW_LEVEL}",
meta.max_level
)));
}
let mut nodes = BTreeMap::new();
let mut active = BTreeMap::new();
let mut deleted_count = 0_usize;
for snapshot in snapshots {
validate_vector_values(dimensions, &snapshot.raw_vector)?;
if snapshot.level > MAX_HNSW_LEVEL {
return Err(corrupt(&format!(
"node {} level {} exceeds the supported maximum {MAX_HNSW_LEVEL}",
snapshot.node_id, snapshot.level
)));
}
if snapshot.neighbors.len() != snapshot.level + 1 {
return Err(corrupt(&format!(
"node {} has level {} but {} adjacency layers",
snapshot.node_id,
snapshot.level,
snapshot.neighbors.len()
)));
}
let (normalized_vector, norm) = normalize_with_norm(&snapshot.raw_vector);
let node = HNSWNode {
id: snapshot.node_id,
doc_id: snapshot.doc_id,
vector_ordinal: snapshot.vector_ordinal,
norm,
normalized_vector,
raw_vector: snapshot.raw_vector,
level: snapshot.level,
deleted: snapshot.deleted,
neighbors: snapshot.neighbors,
};
if nodes.insert(node.id, node.clone()).is_some() {
return Err(corrupt(&format!("duplicate node id {}", node.id)));
}
if node.deleted {
deleted_count = deleted_count
.checked_add(1)
.ok_or_else(|| corrupt("deleted-node counter overflow"))?;
} else if active
.insert((node.doc_id, node.vector_ordinal), node.id)
.is_some()
{
return Err(corrupt(&format!(
"duplicate live vector {}:{}",
node.doc_id, node.vector_ordinal
)));
}
}
let index = Self {
dimensions,
params,
nodes,
active,
entry_point: meta.entry_point,
max_level: meta.max_level,
next_node_id: meta.next_node_id,
deleted_count,
dirty_nodes: BTreeSet::new(),
full_rewrite: false,
};
if meta.live_count != index.active.len() || meta.deleted_count != index.deleted_count {
return Err(corrupt(&format!(
"counter mismatch: metadata live/deleted={}/{}, graph={}/{}",
meta.live_count,
meta.deleted_count,
index.active.len(),
index.deleted_count
)));
}
index.validate_invariants()?;
Ok(index)
}
}
fn corrupt(message: &str) -> StorageBackendError {
StorageBackendError::Other(format!("corrupt HNSW graph: {message}"))
}