Merge feat/search-harness: search harness, HNSW recall fix, incremental BM25, persisted vector index
CI / test (push) Failing after 2s

Co-Authored-By: Claude Fable 5.1 <[email protected]>
This commit is contained in:
osobh
2026-09-19 13:17:05 -07:00
co-authored by Claude Fable 5.1
11 changed files with 1763 additions and 148 deletions
+148
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@@ -28,6 +28,154 @@
---
## Search harness baseline (v2.3.0)
Produced by `cargo run --release -p clawhdf5-bench --bin search_harness -- --full`
on deterministic **clustered** synthetic data (384-dim, unit-normalised; points =
cluster centre + noise — uniform random vectors are nearly equidistant in high
dimension and say nothing about embeddings). Recall is measured against an exact
brute-force scan, 200 queries. This is the *before* picture for the search
hot-path work; every change to that path should be justified by a re-run.
Two things stand out:
* **HNSW recall does not respond to `ef`** and degrades sharply with size
(0.87 → 0.67 → 0.31 recall@10 at 1K / 10K / 100K). Latency plateaus at the same
point, i.e. the search exhausts the nodes it can reach: on clustered data the
graph is poorly connected. The index selects neighbours by plain top-M
distance rather than the HNSW paper's diversity heuristic.
* **End-to-end `hybrid_search` is ~1000x slower than its vector stage** (49 ms
vs ~0.03 ms at 10K; 884 ms at 100K). Each query rebuilds the BM25 index from
scratch and rewrites the whole `.h5` file. The first query after `open()`
additionally rebuilds the HNSW index (10.5 s at 100K).
### HNSW, N = 1000, dim = 384, M = 16, ef_construction = 64
build: 72.4 ms (13818 vectors/s) · exact scan: 3854 QPS, p50 258 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.8710 | 59484 | 16 | 31 |
| 32 | 0.8730 | 46302 | 21 | 25 |
| 64 | 0.8730 | 31683 | 31 | 44 |
| 128 | 0.8730 | 24715 | 40 | 49 |
| 256 | 0.8730 | 24788 | 40 | 50 |
### HNSW, N = 10000, dim = 384, M = 16, ef_construction = 64
build: 802.5 ms (12461 vectors/s) · exact scan: 418 QPS, p50 2363 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.6695 | 44031 | 19 | 51 |
| 32 | 0.6705 | 45066 | 22 | 30 |
| 64 | 0.6705 | 32746 | 30 | 41 |
| 128 | 0.6705 | 27542 | 36 | 51 |
| 256 | 0.6705 | 27754 | 36 | 49 |
### HNSW, N = 100000, dim = 384, M = 16, ef_construction = 64
build: 9752.6 ms (10254 vectors/s) · exact scan: 40 QPS, p50 24648 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.3085 | 18046 | 57 | 84 |
| 32 | 0.3110 | 21621 | 43 | 75 |
| 64 | 0.3130 | 20015 | 49 | 70 |
| 128 | 0.3135 | 15822 | 63 | 99 |
| 256 | 0.3135 | 15308 | 66 | 124 |
### End to end: `HDF5Memory::hybrid_search` (k = 10, weights 0.7 / 0.3)
| N | ingest ms | checkpoint ms | open ms | first query ms | p50 ms | p99 ms | QPS |
|---:|---:|---:|---:|---:|---:|---:|---:|
| 1000 | 11 | 3.9 | 0.9 | 68.1 | 5.48 | 5.57 | 182.5 |
| 10000 | 114 | 32.2 | 10.9 | 845.0 | 48.56 | 78.65 | 19.8 |
| 100000 | 1486 | 713.0 | 354.5 | 10486.5 | 883.51 | 975.23 | 1.1 |
wrote /tmp/claude-1000/-home-osobh-projects-clawhdf5/422f755e-dd25-4c35-8613-5439087e3aaa/scratchpad/baseline_full.json
### After: HNSW neighbour-selection heuristic
Same harness, same data, after replacing closest-M neighbour selection with the
HNSW paper's diversity heuristic (Algorithm 4, keeping pruned connections) for
both new links and back-link pruning. Recall@10 at `ef = 64`: **0.87 → 1.00**
(1K), **0.67 → 1.00** (10K), **0.31 → 0.98** (100K), and it now rises with
`ef` as it should. The cost is a slower build (extra distance evaluations per
insert: ~3.5x at 10K); the distance-kernel work that follows targets that.
### HNSW, N = 1000, dim = 384, M = 16, ef_construction = 64
build: 221.3 ms (4519 vectors/s) · exact scan: 3851 QPS, p50 258 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.9990 | 54760 | 18 | 29 |
| 32 | 1.0000 | 40422 | 24 | 44 |
| 64 | 1.0000 | 27744 | 36 | 51 |
| 128 | 1.0000 | 13164 | 74 | 106 |
| 256 | 1.0000 | 6879 | 144 | 175 |
### HNSW, N = 10000, dim = 384, M = 16, ef_construction = 64
build: 2733.5 ms (3658 vectors/s) · exact scan: 423 QPS, p50 2362 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.9975 | 31321 | 27 | 61 |
| 32 | 1.0000 | 32427 | 29 | 48 |
| 64 | 1.0000 | 22738 | 42 | 62 |
| 128 | 1.0000 | 10055 | 99 | 129 |
| 256 | 1.0000 | 4649 | 214 | 266 |
### HNSW, N = 100000, dim = 384, M = 16, ef_construction = 64
build: 36472.8 ms (2742 vectors/s) · exact scan: 40 QPS, p50 24644 µs
| ef | recall@10 | QPS | p50 µs | p99 µs |
|---:|---:|---:|---:|---:|
| 16 | 0.9235 | 11394 | 82 | 194 |
| 32 | 0.9675 | 12788 | 73 | 161 |
| 64 | 0.9840 | 10406 | 91 | 186 |
| 128 | 0.9990 | 7633 | 126 | 248 |
| 256 | 0.9990 | 2823 | 352 | 510 |
### After: persistent keyword index, no store rewrite per query
`hybrid_search` used to rebuild the BM25 index from scratch (re-tokenising every
record) and rewrite the whole `.h5` file on **every query**. The index is now
kept for the life of the store and updated incrementally, and activation boosts
are persisted by the next checkpoint instead of inside the query. Steady-state
p50: **5.5 → 0.24 ms** (1K), **49 → 2.1 ms** (10K), **884 → 23 ms** (100K).
The first query after `open()` is slower than before (it pays for the better —
slower — HNSW build plus the one-off keyword index build); persisting the HNSW
index removes that.
### End to end: `HDF5Memory::hybrid_search` (k = 10, weights 0.7 / 0.3)
| N | ingest ms | checkpoint ms | open ms | first query ms | p50 ms | p99 ms | QPS |
|---:|---:|---:|---:|---:|---:|---:|---:|
| 1000 | 11 | 3.8 | 0.9 | 195.9 | 0.24 | 0.27 | 4130.4 |
| 10000 | 104 | 31.1 | 10.9 | 2627.1 | 2.09 | 2.11 | 479.5 |
| 100000 | 1436 | 684.7 | 278.0 | 36308.1 | 22.90 | 25.46 | 43.5 |
### After: vector index persisted with the checkpoint
The HNSW graph (not the vectors, which the store already holds) is saved to
`<store>.h5.ann` at each checkpoint and reloaded by `open()`, tied to that
checkpoint by a generation id. The index is now built once per store (the *cold
index build* column — the first query ever), not once per session. First query
after `open()`: **196 → 1.7 ms** (1K), **2627 → 15 ms** (10K),
**36308 → 159 ms** (100K); what remains is the one-off keyword index build.
Batch saves no longer force a full rebuild either: appended records join the
index incrementally.
| N | ingest ms | cold index build ms | checkpoint ms | open ms | first query after open ms | p50 ms | p99 ms | QPS |
|---:|---:|---:|---:|---:|---:|---:|---:|---:|
| 1000 | 14 | 220 | 6.1 | 1.2 | 1.7 | 0.24 | 0.27 | 4049.9 |
| 10000 | 120 | 2916 | 33.1 | 14.0 | 15.4 | 2.15 | 3.30 | 421.2 |
| 100000 | 1591 | 40515 | 747.3 | 324.7 | 158.9 | 23.07 | 30.42 | 41.3 |
## Vector Search Latency
Brute-force cosine similarity over 384-dimensional embeddings (OpenAI text-embedding-3-small size).
+41
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@@ -1,5 +1,46 @@
# Changelog
## Unreleased
### Search
- `clawhdf5-ann`: **HNSW recall fix.** Neighbours were chosen as the plain
closest-M, which on clustered data (what embeddings look like) turns each
cluster into an island: recall@10 was 0.87 / 0.67 / 0.31 at 1K / 10K / 100K
vectors and did not improve with `ef`. The index now uses the HNSW paper's
diversity heuristic (Algorithm 4 with kept pruned connections) when linking a
new node and when pruning back-links: recall@10 at `ef = 64` is 1.00 / 1.00 /
0.98 and responds to `ef`. Builds are slower (~3.5x at 10K). Existing
persisted indexes keep their old graph until rebuilt; the agent rebuilds its
index from the cache, so stores pick this up automatically.
- `clawhdf5-agent`: **`hybrid_search` is 23-39x faster in steady state** (p50
5.5 -> 0.24 ms at 1K records, 49 -> 2.1 ms at 10K, 884 -> 23 ms at 100K).
Every query used to rebuild the BM25 index from scratch and rewrite the whole
`.h5` file. The keyword index now lives for the life of the store and is
updated incrementally (add / remove / in-place update, exactly equivalent to
a fresh build - property-tested), and a query no longer writes the store.
**Behaviour change:** Hebbian activation boosts are persisted by the next
checkpoint (any flushing write, `flush_wal`, or drop) rather than
immediately; a crash in between forgets only the boosts since the last
checkpoint. Activation weights are now capped (16.0) - they grew without
bound.
- `clawhdf5-agent`: **the vector index is persisted**, so `open()` no longer
rebuilds it on the first search (first query after open: 2627 -> 15 ms at 10K
records, 36 s -> 159 ms at 100K). The HNSW graph — not the vectors, which the
store already holds — is written to `<store>.h5.ann` at each checkpoint and
tied to it by a generation id in `/meta`; a missing, stale, damaged or
structurally invalid sidecar is ignored and the index rebuilt. Records
replayed from the WAL join the loaded index incrementally; a replayed update
or delete invalidates it. `snapshot()` copies it. Batch saves no longer force
a full index rebuild.
- `clawhdf5-ann`: `HnswIndex::graph_to_bytes` / `from_graph_bytes` — graph-only
serialization (checksummed, every neighbour id and level validated on load).
- `clawhdf5-agent`: BM25 results are deterministic (ties break by record id),
top-k uses a bounded heap, and the "WAND early termination" that computed a
bound and then ignored it is gone. IDF is computed per query.
- `clawhdf5-bench`: new `search_harness` binary — HNSW recall@10 / QPS / latency
per `ef` against an exact scan, and end-to-end `hybrid_search` timings, on
deterministic clustered (or `--uniform`) data. Baseline in `BENCHMARKS.md`.
## v2.3.0 (2026-09-19)
### Upgrade Notes
+10
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@@ -33,6 +33,16 @@ Cargo workspace with 16 crates under `crates/` (plus `libaec-sys`, an internal F
the approximate `clawhdf5-ann` index for the vector stage (the index mirrors
the cache and self-heals on drift). Build the agent with
`--no-default-features --features float16` to force the exact linear cosine scan.
The index uses the HNSW paper's diversity heuristic for neighbour selection
(plain closest-M capped recall on clustered data: 0.31 recall@10 at 100K). Its
graph is saved to `<store>.h5.ann` at each checkpoint and reloaded by `open()`
(tied to the checkpoint by a generation id; stale/damaged sidecars are
ignored and the index rebuilt). `hybrid_search` keeps one incremental BM25
index for the life of the store and never writes the store: Hebbian
activation boosts are persisted by the next checkpoint (or on drop), not per
query. Measure any search-path change with
`cargo run --release -p clawhdf5-bench --bin search_harness` (baselines in
`BENCHMARKS.md`).
- WAL (write-ahead log) for crash-safe persistence, with a chained CRC32
trailer per entry (each entry's CRC folds in the previous entry's CRC) so a
corrupted, reordered, duplicated, or spliced entry stops replay cleanly
+217 -113
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@@ -3,10 +3,15 @@
//! Provides a standard BM25 (Okapi BM25) implementation with an in-memory
//! inverted index. Tombstoned documents are excluded from indexing and search.
//!
//! Optimizations:
//! - Cached IDF scores (don't recompute per query)
//! - Sorted posting lists by doc_id for cache-friendly access
//! - Block-Max WAND early termination
//! The index is **incremental**: [`BM25Index::add_document`] and
//! [`BM25Index::remove_document`] keep it exactly equivalent to one built from
//! scratch over the same live documents, so a store can maintain one index for
//! its lifetime instead of re-tokenising the whole corpus per query. To make
//! that possible IDF is computed at query time (it depends on the live
//! document count) rather than cached at build time.
//!
//! - Posting lists sorted by doc id
//! - Bounded-heap top-k; results ordered by score, then doc id (deterministic)
use std::cmp::Reverse;
use std::collections::{BinaryHeap, HashMap};
@@ -41,10 +46,11 @@ const DEFAULT_B: f32 = 0.75;
pub struct BM25Index {
/// Inverted index: token -> sorted list of (doc_id, term_frequency).
inverted: HashMap<String, Vec<(usize, u32)>>,
/// Cached IDF scores per token.
idf_cache: HashMap<String, f32>,
/// Number of tokens in each document (0 for tombstoned docs).
doc_lengths: Vec<u32>,
/// Sum of `doc_lengths` over live documents (keeps `avg_dl` exact under
/// incremental updates).
total_length: u64,
/// Average document length across non-tombstoned docs.
avg_dl: f32,
/// Number of non-tombstoned documents.
@@ -60,8 +66,8 @@ impl BM25Index {
pub fn build(documents: &[String], tombstones: &[u8]) -> Self {
let mut index = Self {
inverted: HashMap::new(),
idf_cache: HashMap::new(),
doc_lengths: vec![0; documents.len()],
total_length: 0,
avg_dl: 0.0,
num_docs: 0,
k1: DEFAULT_K1,
@@ -81,103 +87,135 @@ impl BM25Index {
return Vec::new();
}
let tokens = tokenize(query);
if tokens.is_empty() {
return Vec::new();
}
// Collect posting lists and cached IDF scores for query tokens
type QueryTerm<'a> = (&'a str, f32, &'a [(usize, u32)]);
let mut query_terms: Vec<QueryTerm<'_>> = Vec::new();
for token in &tokens {
if let (Some(postings), Some(&idf)) = (
self.inverted.get(token.as_str()),
self.idf_cache.get(token.as_str()),
) {
query_terms.push((token, idf, postings));
}
}
if query_terms.is_empty() {
return Vec::new();
}
// Accumulate BM25 scores per document using WAND-style scoring
// Term-at-a-time accumulation. IDF is computed here rather than cached
// at build time: it depends on the live document count, which changes
// with every incremental add/remove, and costs one `ln` per query term.
let mut scores: HashMap<usize, f32> = HashMap::new();
// Compute maximum possible contribution per term for WAND
let max_tf_score: Vec<f32> = query_terms
.iter()
.map(|(_, idf, _)| {
// Upper bound: max TF contribution when tf is high and dl is short
let max_tf_num = 10.0 * (self.k1 + 1.0);
let max_tf_den = 10.0 + self.k1 * (1.0 - self.b);
idf * max_tf_num / max_tf_den
})
.collect();
let total_max_contribution: f32 = max_tf_score.iter().sum();
// Threshold for WAND early termination. `top_k_heap` is a min-heap of
// size k (worst-of-the-top-k at the head) so it can be maintained in
// O(log k) per update instead of re-sorting the whole buffer.
let mut threshold = 0.0f32;
let mut top_k_heap: BinaryHeap<Reverse<HeapScore>> = BinaryHeap::with_capacity(k);
for (term_idx, (_, idf, postings)) in query_terms.iter().enumerate() {
for &(doc_id, freq) in *postings {
for token in tokenize(query) {
let Some(postings) = self.inverted.get(token.as_str()) else {
continue;
};
let df = postings.len() as f32;
let idf = ((self.num_docs as f32 - df + 0.5) / (df + 0.5) + 1.0).ln();
for &(doc_id, freq) in postings {
let dl = self.doc_lengths[doc_id] as f32;
let freq_f = freq as f32;
let tf = (freq_f * (self.k1 + 1.0))
/ (freq_f + self.k1 * (1.0 - self.b + self.b * dl / self.avg_dl));
let contribution = idf * tf;
let entry = scores.entry(doc_id).or_insert(0.0);
*entry += contribution;
// WAND check: if this doc's current partial score + remaining
// max terms can't beat threshold, we can skip (but we still
// accumulate since we process term-at-a-time)
if term_idx == query_terms.len() - 1 {
// Last term: check if this doc beats threshold
let final_score = *entry;
if top_k_heap.len() >= k {
if final_score > threshold {
// Replace the current worst-of-top-k.
top_k_heap.pop();
top_k_heap.push(Reverse(HeapScore(final_score)));
threshold = top_k_heap.peek().map(|Reverse(s)| s.0).unwrap_or(0.0);
}
} else {
top_k_heap.push(Reverse(HeapScore(final_score)));
if top_k_heap.len() == k {
threshold = top_k_heap.peek().map(|Reverse(s)| s.0).unwrap_or(0.0);
}
}
}
}
// After processing each term, check if remaining terms can
// possibly produce results above threshold
let remaining_max: f32 = max_tf_score[term_idx + 1..].iter().sum();
if remaining_max < threshold && total_max_contribution > 0.0 {
// Early termination: remaining terms can't produce new top-k
// entries on their own. But existing partial scores may still
// be updated, so we continue (WAND is approximate here).
let _ = remaining_max; // hint to compiler
*scores.entry(doc_id).or_insert(0.0) += idf * tf;
}
}
let mut results: Vec<(usize, f32)> = scores.into_iter().collect();
results.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
results.truncate(k);
// Top-k with a bounded min-heap: O(matches * log k) instead of sorting
// every match. Ties break towards the lower doc id so results are
// deterministic (the accumulator is a HashMap).
let mut heap: BinaryHeap<Reverse<(HeapScore, Reverse<usize>)>> =
BinaryHeap::with_capacity(k + 1);
for (doc_id, score) in scores {
heap.push(Reverse((HeapScore(score), Reverse(doc_id))));
if heap.len() > k {
heap.pop();
}
}
let mut results: Vec<(usize, f32)> = heap
.into_iter()
.map(|Reverse((HeapScore(score), Reverse(doc_id)))| (doc_id, score))
.collect();
results.sort_by(|a, b| b.1.total_cmp(&a.1).then(a.0.cmp(&b.0)));
results
}
/// Number of document slots (live or not) the index covers. Ids are
/// positions in the document list it mirrors.
pub fn len(&self) -> usize {
self.doc_lengths.len()
}
/// `true` when the index covers no document slots.
pub fn is_empty(&self) -> bool {
self.doc_lengths.is_empty()
}
/// Index `text` as document `doc_id`, which must be the next free id
/// (`self.len()`) or an existing slot that is currently empty (removed or
/// tombstoned). After any sequence of `add_document` / `remove_document`
/// calls the index scores exactly as one freshly built from the same live
/// documents.
pub fn add_document(&mut self, doc_id: usize, text: &str) {
if doc_id >= self.doc_lengths.len() {
self.doc_lengths.resize(doc_id + 1, 0);
}
debug_assert_eq!(self.doc_lengths[doc_id], 0, "slot {doc_id} is occupied");
let tokens = tokenize(text);
let mut term_freqs: HashMap<&str, u32> = HashMap::new();
for token in &tokens {
*term_freqs.entry(token).or_insert(0) += 1;
}
for (token, freq) in term_freqs {
let postings = self.inverted.entry(token.to_string()).or_default();
// Posting lists stay sorted by doc id; appends are the common case.
match postings.last() {
Some(&(last, _)) if last >= doc_id => {
let at = postings.partition_point(|&(id, _)| id < doc_id);
postings.insert(at, (doc_id, freq));
}
_ => postings.push((doc_id, freq)),
}
}
self.doc_lengths[doc_id] = tokens.len() as u32;
self.total_length += tokens.len() as u64;
self.num_docs += 1;
self.refresh_avg_dl();
}
/// Extend the index to cover `len` document slots, leaving new ones empty.
/// Used for slots that hold no live document (tombstoned records).
pub fn pad_to(&mut self, len: usize) {
if len > self.doc_lengths.len() {
self.doc_lengths.resize(len, 0);
}
}
/// Remove document `doc_id`, whose indexed text was `text`. The text is
/// needed to find its postings; pass exactly what was added.
pub fn remove_document(&mut self, doc_id: usize, text: &str) {
let tokens = tokenize(text);
let mut seen: std::collections::HashSet<&str> = std::collections::HashSet::new();
for token in &tokens {
if !seen.insert(token) {
continue;
}
if let Some(postings) = self.inverted.get_mut(token.as_str()) {
if let Ok(at) = postings.binary_search_by_key(&doc_id, |&(id, _)| id) {
postings.remove(at);
}
if postings.is_empty() {
self.inverted.remove(token.as_str());
}
}
}
if let Some(len) = self.doc_lengths.get_mut(doc_id) {
self.total_length = self.total_length.saturating_sub(u64::from(*len));
*len = 0;
}
self.num_docs = self.num_docs.saturating_sub(1);
self.refresh_avg_dl();
}
fn refresh_avg_dl(&mut self) {
self.avg_dl = if self.num_docs > 0 {
self.total_length as f32 / self.num_docs as f32
} else {
0.0
};
}
/// Rebuild the index from scratch (e.g., after compaction).
pub fn rebuild(&mut self, documents: &[String], tombstones: &[u8]) {
self.inverted.clear();
self.idf_cache.clear();
self.doc_lengths = vec![0; documents.len()];
self.total_length = 0;
self.avg_dl = 0.0;
self.num_docs = 0;
self.index_documents(documents, tombstones);
@@ -214,23 +252,13 @@ impl BM25Index {
}
self.num_docs = count;
self.avg_dl = if count > 0 {
total_length as f32 / count as f32
} else {
0.0
};
self.total_length = total_length;
self.refresh_avg_dl();
// Sort posting lists by doc_id for cache-friendly access
for postings in self.inverted.values_mut() {
postings.sort_by_key(|&(doc_id, _)| doc_id);
}
// Pre-compute and cache IDF scores
for (token, postings) in &self.inverted {
let df = postings.len() as f32;
let idf = ((self.num_docs as f32 - df + 0.5) / (df + 0.5) + 1.0).ln();
self.idf_cache.insert(token.clone(), idf);
}
}
}
@@ -386,24 +414,21 @@ mod tests {
}
#[test]
fn cached_idf_consistent_with_computed() {
fn score_matches_the_bm25_formula() {
let docs = vec![
"rust programming".to_string(),
"rust systems".to_string(),
"python scripting".to_string(),
];
let tombstones = vec![0, 0, 0];
let index = BM25Index::build(&docs, &tombstones);
let index = BM25Index::build(&docs, &[0, 0, 0]);
// IDF for "rust" (appears in 2 of 3 docs)
let idf_rust = index.idf_cache.get("rust").unwrap();
let expected_idf = ((3.0f32 - 2.0 + 0.5) / (2.0 + 0.5) + 1.0).ln();
assert!(
(idf_rust - expected_idf).abs() < 1e-6,
"cached IDF mismatch: {} vs {}",
idf_rust,
expected_idf
);
// "python": df = 1 of N = 3. Every doc has the average length (2) and
// tf = 1, so the tf factor is exactly 1 and the score is the IDF.
let results = index.search("python", 3);
let expected_idf = ((3.0f32 - 1.0 + 0.5) / (1.0 + 0.5) + 1.0).ln();
assert_eq!(results.len(), 1);
assert_eq!(results[0].0, 2);
assert!((results[0].1 - expected_idf).abs() < 1e-6, "{results:?}");
}
#[test]
@@ -467,4 +492,83 @@ mod tests {
);
}
}
/// Documents drawn from a small vocabulary so terms collide heavily.
fn random_doc(state: &mut u64) -> String {
const VOCAB: &[&str] = &[
"alpha", "beta", "gamma", "delta", "eps", "zeta", "eta", "x1",
];
let mut next = || {
*state = state
.wrapping_mul(6364136223846793005)
.wrapping_add(1442695040888963407);
(*state >> 33) as usize
};
let len = 1 + next() % 9;
(0..len)
.map(|_| VOCAB[next() % VOCAB.len()])
.collect::<Vec<_>>()
.join(" ")
}
#[test]
fn incremental_updates_match_a_fresh_build_exactly() {
for seed in 0..60u64 {
let mut state = seed.wrapping_mul(0x9E37_79B9_7F4A_7C15) | 1;
let mut docs: Vec<String> = Vec::new();
let mut tombstones: Vec<u8> = Vec::new();
let mut index = BM25Index::build(&docs, &tombstones);
for step in 0..80 {
state = state.wrapping_mul(6364136223846793005).wrapping_add(1);
let live: Vec<usize> = (0..docs.len()).filter(|&i| tombstones[i] == 0).collect();
match (state >> 40) % 4 {
0 if !live.is_empty() => {
// delete
let id = live[(state >> 20) as usize % live.len()];
index.remove_document(id, &docs[id]);
tombstones[id] = 1;
}
1 if !live.is_empty() => {
// update in place
let id = live[(state >> 20) as usize % live.len()];
let new_text = random_doc(&mut state);
index.remove_document(id, &docs[id]);
index.add_document(id, &new_text);
docs[id] = new_text;
}
_ => {
let text = random_doc(&mut state);
index.add_document(docs.len(), &text);
docs.push(text);
tombstones.push(0);
}
}
let fresh = BM25Index::build(&docs, &tombstones);
for query in ["alpha", "beta gamma", "x1 zeta alpha delta", "missing"] {
let got = index.search(query, 5);
let want = fresh.search(query, 5);
assert_eq!(got.len(), want.len(), "seed {seed} step {step} {query:?}");
for (g, w) in got.iter().zip(&want) {
assert_eq!(
g.0, w.0,
"seed {seed} step {step} {query:?}: {got:?} vs {want:?}"
);
assert!(
(g.1 - w.1).abs() < 1e-5,
"seed {seed} step {step} {query:?}"
);
}
}
}
}
}
#[test]
fn ties_break_towards_the_lower_doc_id() {
let docs: Vec<String> = (0..6).map(|_| "same text".to_string()).collect();
let index = BM25Index::build(&docs, &[0; 6]);
let ids: Vec<usize> = index.search("same", 3).into_iter().map(|r| r.0).collect();
assert_eq!(ids, [0, 1, 2]);
}
}
+447 -11
View File
@@ -205,6 +205,12 @@ pub trait AgentMemory {
fn get_session_summary(&self, session_id: &str) -> Result<Option<String>>;
}
/// Ceiling for a record's Hebbian activation weight. Each hit adds
/// `hebbian_boost` and the fused score is scaled by `sqrt(weight)`, so without
/// a cap a frequently returned record's advantage grows without limit and it
/// eventually outranks better matches purely on popularity.
pub(crate) const MAX_ACTIVATION_WEIGHT: f32 = 16.0;
/// Most anomaly alerts kept between `take_anomaly_alerts` calls.
const MAX_PENDING_ALERTS: usize = 1024;
@@ -247,6 +253,14 @@ pub struct HDF5Memory {
/// via [`HDF5Memory::take_anomaly_alerts`]. Saves are never blocked on
/// these — surfacing is opt-in for callers that want to act on them.
anomaly_alerts: Vec<anomaly::AnomalyAlert>,
/// Keyword index over `cache.chunks`, kept for the life of the store and
/// updated incrementally — it used to be rebuilt from scratch, re-tokenising
/// every record, on every single query. Built lazily on first use; see
/// [`HDF5Memory::ensure_bm25_fresh`] for how it stays in sync.
bm25: Option<bm25::BM25Index>,
/// Activation weights changed since the last checkpoint (searches boost
/// the records they return). Cleared by `flush`.
activations_dirty: bool,
/// Opened with [`HDF5Memory::open_read_only`]: nothing may reach the disk.
read_only: bool,
/// A WAL that `open()` could not read and moved aside; see
@@ -299,6 +313,8 @@ impl HDF5Memory {
provenance: provenance::ProvenanceStore::new(),
anomaly: anomaly::WriteAnomalyDetector::new(anomaly::AnomalyConfig::default()),
anomaly_alerts: Vec::new(),
bm25: None,
activations_dirty: false,
read_only: false,
quarantined_wal: None,
_lock: Some(lock),
@@ -374,8 +390,13 @@ impl HDF5Memory {
} else {
Some(store_lock::StoreLock::acquire(path)?)
};
let ((config, mut cache, sessions, knowledge), wal_applied) =
storage::read_from_disk_with_mark(path)?;
let ((config, mut cache, sessions, knowledge), checkpoint) =
storage::read_from_disk_with_meta(path)?;
let wal_applied = checkpoint.wal_applied;
let n_checkpoint = cache.len();
// Set if WAL replay did anything other than append records; the saved
// vector index then no longer describes the first `n_checkpoint` ones.
let mut replay_only_appended = true;
// Replay WAL if present
let wal_path = path.with_extension("h5.wal");
@@ -392,6 +413,9 @@ impl HDF5Memory {
&& let Ok(entries) =
wal::WalFile::read_entries_for_migration(&wal_path, wal_applied)
{
replay_only_appended &= entries
.iter()
.all(|e| e.entry_type == wal::WalEntryType::Save);
wal::replay_into_cache(&entries, &mut cache);
}
None
@@ -403,6 +427,9 @@ impl HDF5Memory {
// in case the process died between writing the .h5 and
// truncating the WAL.
let entries = wal::WalFile::read_entries_for_migration(&wal_path, wal_applied)?;
replay_only_appended &= entries
.iter()
.all(|e| e.entry_type == wal::WalEntryType::Save);
wal::replay_into_cache(&entries, &mut cache);
Some(wal::WalFile::open(&wal_path)?)
} else if config.wal_enabled {
@@ -411,6 +438,25 @@ impl HDF5Memory {
None
};
#[cfg(feature = "hnsw")]
let loaded_index = if replay_only_appended {
Self::load_vector_index(path, checkpoint.ann_generation, &cache, n_checkpoint)
} else {
None
};
#[cfg(not(feature = "hnsw"))]
let _ = (
n_checkpoint,
replay_only_appended,
checkpoint.ann_generation,
);
#[cfg(feature = "hnsw")]
let synced_len = if loaded_index.is_some() {
cache.len()
} else {
0
};
Ok(Self {
config,
cache,
@@ -419,14 +465,14 @@ impl HDF5Memory {
wal,
strategy: None,
ephemeral: None,
// Existing data is loaded from disk + WAL replay; mark the index
// dirty so it is (re)built from the cache on the first search.
// Reuse the vector index saved with the checkpoint when there is
// one; otherwise mark it dirty so the first search builds it.
#[cfg(feature = "hnsw")]
hnsw: None,
hnsw_dirty: loaded_index.is_none(),
#[cfg(feature = "hnsw")]
hnsw_dirty: true,
hnsw_synced_len: synced_len,
#[cfg(feature = "hnsw")]
hnsw_synced_len: 0,
hnsw: loaded_index,
// No on-disk provenance ledger exists yet (see CLAUDE.md), so
// there's no historical hash to verify loaded records against —
// the store starts empty and is populated as records are
@@ -434,12 +480,151 @@ impl HDF5Memory {
provenance: provenance::ProvenanceStore::new(),
anomaly: anomaly::WriteAnomalyDetector::new(anomaly::AnomalyConfig::default()),
anomaly_alerts: Vec::new(),
bm25: None,
activations_dirty: false,
read_only,
quarantined_wal,
_lock: lock,
})
}
/// Where the vector index graph is kept between sessions.
#[cfg_attr(not(feature = "hnsw"), allow(dead_code))]
fn vector_index_path(store: &Path) -> PathBuf {
store.with_extension("h5.ann")
}
/// Save the vector index graph next to the store, returning the generation
/// id the checkpoint must record for it. Only an index that exactly mirrors
/// the cache is saved; otherwise any stale sidecar is removed and `None`
/// returned, and the next session rebuilds. Failures are not errors — the
/// sidecar is a cache of derived data.
#[cfg(feature = "hnsw")]
fn persist_vector_index(&self) -> Option<u64> {
let path = Self::vector_index_path(&self.config.path);
let index = match self.hnsw.as_ref() {
Some(index)
if !self.hnsw_dirty
&& self.hnsw_synced_len == self.cache.embeddings.len()
&& index.len() == self.cache.embeddings.len() =>
{
index
}
_ => {
let _ = std::fs::remove_file(&path);
return None;
}
};
static COUNTER: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(0);
let nanos = std::time::SystemTime::now()
.duration_since(std::time::UNIX_EPOCH)
.map_or(0, |d| d.as_nanos() as u64);
let generation = nanos
^ (u64::from(std::process::id()) << 32)
^ COUNTER.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
let mut bytes = generation.to_le_bytes().to_vec();
bytes.extend_from_slice(&index.graph_to_bytes());
let tmp = path.with_extension("ann.tmp");
let written =
storage::write_synced(&tmp, &bytes).and_then(|()| storage::rename_synced(&tmp, &path));
match written {
Ok(()) => Some(generation),
Err(_) => {
let _ = std::fs::remove_file(&tmp);
let _ = std::fs::remove_file(&path);
None
}
}
}
#[cfg(not(feature = "hnsw"))]
fn persist_vector_index(&self) -> Option<u64> {
None
}
/// Load the vector index saved with the checkpoint identified by
/// `generation`, covering the first `n_checkpoint` records of `cache`.
/// Anything unexpected — no sidecar, another generation, a damaged or
/// mismatched graph — yields `None` and the index is rebuilt on demand.
#[cfg(feature = "hnsw")]
fn load_vector_index(
store: &Path,
generation: Option<u64>,
cache: &MemoryCache,
n_checkpoint: usize,
) -> Option<HnswIndex> {
let generation = generation?;
let bytes = std::fs::read(Self::vector_index_path(store)).ok()?;
let (stamp, graph) = bytes.split_at_checked(8)?;
if u64::from_le_bytes(stamp.try_into().ok()?) != generation {
return None;
}
let vectors = cache.embeddings.get(..n_checkpoint)?.to_vec();
let mut index = HnswIndex::from_graph_bytes(graph, vectors).ok()?;
if index.dimension() != cache.embedding_dim {
return None;
}
// Records appended since (replayed from the WAL) join incrementally.
for id in n_checkpoint..cache.embeddings.len() {
if cache.embeddings[id].len() != index.dimension()
|| index.insert(cache.embeddings[id].clone()) != id
{
return None;
}
}
for (id, &t) in cache.tombstones.iter().enumerate() {
if t != 0 {
index.mark_deleted(id);
}
}
Some(index)
}
/// Bring the keyword index in line with the cache and return it.
///
/// Appends need no hook: records the index hasn't seen yet (whatever path
/// added them) are indexed here, in order. Changes that keep the length the
/// same are reported explicitly — [`Self::bm25_on_delete`] and
/// [`Self::bm25_on_update`] — and anything that renumbers records
/// (compaction) drops the index so it is rebuilt.
pub(crate) fn ensure_bm25_fresh(&mut self) -> &bm25::BM25Index {
let n = self.cache.chunks.len();
let bm25 = match self.bm25.take() {
Some(index) if index.len() <= n => {
let mut index = index;
for id in index.len()..n {
if self.cache.tombstones[id] == 0 {
index.add_document(id, &self.cache.chunks[id]);
}
}
index.pad_to(n);
index
}
_ => bm25::BM25Index::build(&self.cache.chunks, &self.cache.tombstones),
};
self.bm25.insert(bm25)
}
/// Record `id` was tombstoned; its text is still in the cache.
fn bm25_on_delete(&mut self, id: usize) {
if let Some(index) = self.bm25.as_mut()
&& id < index.len()
{
index.remove_document(id, &self.cache.chunks[id]);
}
}
/// Record `id`'s text changed from `old_text` to what the cache holds now.
fn bm25_on_update(&mut self, id: usize, old_text: &str) {
if let Some(index) = self.bm25.as_mut()
&& id < index.len()
{
index.remove_document(id, old_text);
index.add_document(id, &self.cache.chunks[id]);
}
}
/// Flush current state to disk and truncate the WAL.
///
/// Every code path that persists the full cache to the .h5 file must
@@ -455,17 +640,24 @@ impl HDF5Memory {
// Record which WAL prefix this checkpoint contains, so a crash before
// the truncate below can't replay those entries a second time.
let wal_applied = self.wal.as_ref().map(|w| w.mark());
storage::write_to_disk_with_mark(
// Written before the .h5 so a crash in between leaves a sidecar whose
// generation matches no checkpoint (ignored), never the reverse.
let ann_generation = self.persist_vector_index();
storage::write_to_disk_with_meta(
&self.config.path,
&self.config,
&self.cache,
&self.sessions,
&self.knowledge,
wal_applied,
&schema::CheckpointMeta {
wal_applied,
ann_generation,
},
)?;
if let Some(ref mut w) = self.wal {
w.truncate()?;
}
self.activations_dirty = false;
Ok(())
}
@@ -623,6 +815,30 @@ impl HDF5Memory {
#[cfg(feature = "hnsw")]
fn ensure_hnsw_fresh(&mut self) {
let n = self.cache.embeddings.len();
// Records appended since the index was last in sync (a batch save, or
// any path that pushes to the cache without a hook) are inserted
// incrementally rather than triggering a rebuild of the whole graph.
if !self.hnsw_dirty
&& self.hnsw_synced_len < n
&& let Some(index) = self.hnsw.as_mut()
&& index.len() == self.hnsw_synced_len
{
let dim = index.dimension();
let appended = (self.hnsw_synced_len..n).all(|id| {
self.cache.embeddings[id].len() == dim
&& index.insert(self.cache.embeddings[id].clone()) == id
});
if appended {
for id in self.hnsw_synced_len..n {
if self.cache.tombstones[id] != 0 {
index.mark_deleted(id);
}
}
self.hnsw_synced_len = n;
} else {
self.hnsw_dirty = true;
}
}
if self.hnsw_dirty || self.hnsw_synced_len != n {
self.hnsw = self.build_hnsw_from_cache();
self.hnsw_synced_len = n;
@@ -777,6 +993,7 @@ impl HDF5Memory {
&entry.session_id,
entry.timestamp,
);
let old_text = std::mem::take(&mut self.cache.chunks[existing_idx]);
self.cache.update(
existing_idx,
entry.chunk,
@@ -785,6 +1002,7 @@ impl HDF5Memory {
entry.timestamp,
entry.session_id,
);
self.bm25_on_update(existing_idx, &old_text);
// In-place embedding change: the index node is stale, force rebuild.
self.hnsw_mark_dirty();
let needs_flush = self
@@ -863,8 +1081,8 @@ impl AgentMemory for HDF5Memory {
);
indices.push(idx);
}
// Batch inserts rebuild the index once rather than node-by-node.
self.hnsw_mark_dirty();
// The vector and keyword indexes pick the new records up
// incrementally the next time they are needed.
self.flush()?;
Ok(indices)
}
@@ -876,6 +1094,7 @@ impl AgentMemory for HDF5Memory {
)));
}
self.hnsw_on_delete(id);
self.bm25_on_delete(id);
self.flush()?;
// Auto-compact if threshold exceeded
@@ -893,6 +1112,7 @@ impl AgentMemory for HDF5Memory {
if removed > 0 {
// Record ids are cache indices, which compaction just renumbered.
self.provenance.remap(&index_map);
self.bm25 = None;
// Compaction renumbers cache indices; rebuild the index to match.
self.hnsw_mark_dirty();
self.flush()?;
@@ -920,6 +1140,13 @@ impl AgentMemory for HDF5Memory {
if self.wal.as_ref().is_some_and(|w| !w.is_empty()) && wal_path.exists() {
storage::snapshot_file(&wal_path, &snapshot.with_extension("h5.wal"))?;
}
// The saved vector index belongs to the checkpoint just copied (its
// generation id is in that .h5), so it is valid for the snapshot too.
// Best effort: without it the snapshot simply rebuilds on first search.
let ann_path = Self::vector_index_path(&self.config.path);
if ann_path.exists() {
let _ = storage::snapshot_file(&ann_path, &Self::vector_index_path(&snapshot));
}
Ok(snapshot)
}
@@ -1172,6 +1399,18 @@ impl HDF5Memory {
// --- Tests ---
impl Drop for HDF5Memory {
/// Best-effort checkpoint of activation weights that only searches have
/// touched. Everything else is already durable through the WAL or an
/// earlier checkpoint; without this a search-only session would forget
/// every boost it made.
fn drop(&mut self) {
if self.activations_dirty && !self.read_only {
let _ = self.flush();
}
}
}
#[cfg(test)]
mod tests {
use super::*;
@@ -1595,6 +1834,203 @@ mod tests {
assert_eq!(restored.cache.chunks, ["checkpointed", "wal-only"]);
}
/// A store with `n` records spread over a few directions, WAL on.
#[cfg(feature = "hnsw")]
fn indexed_store(dir: &TempDir, n: usize) -> (HDF5Memory, PathBuf) {
let mut config = make_config(dir);
config.wal_enabled = true;
config.wal_max_entries = 10_000;
config.compact_threshold = 0.0;
let path = config.path.clone();
let mut mem = HDF5Memory::create(config).unwrap();
for i in 0..n {
let a = i as f32 * 0.37;
mem.save(make_entry(
&format!("rec{i}"),
&[a.cos(), a.sin(), (a * 0.5).cos(), 0.1],
))
.unwrap();
}
(mem, path)
}
#[cfg(feature = "hnsw")]
fn top_ids(mem: &mut HDF5Memory, q: &[f32]) -> Vec<usize> {
mem.hybrid_search(q, "", 1.0, 0.0, 5)
.into_iter()
.map(|r| r.index)
.collect()
}
#[cfg(feature = "hnsw")]
#[test]
fn vector_index_is_reloaded_not_rebuilt() {
let dir = TempDir::new().unwrap();
let (mut mem, path) = indexed_store(&dir, 60);
let q = [0.3f32.cos(), 0.3f32.sin(), 0.9, 0.1];
let expected = top_ids(&mut mem, &q); // builds the index
mem.flush_wal().unwrap(); // checkpoint + sidecar
drop(mem);
assert!(HDF5Memory::vector_index_path(&path).exists());
let mut reopened = HDF5Memory::open(&path).unwrap();
assert!(!reopened.hnsw_dirty, "index should come from the sidecar");
assert_eq!(reopened.hnsw.as_ref().unwrap().len(), 60);
assert_eq!(top_ids(&mut reopened, &q), expected);
}
#[cfg(feature = "hnsw")]
#[test]
fn records_appended_after_the_checkpoint_join_the_loaded_index() {
let dir = TempDir::new().unwrap();
let (mut mem, path) = indexed_store(&dir, 40);
top_ids(&mut mem, &[1.0, 0.0, 0.0, 0.0]);
mem.flush_wal().unwrap();
// Only in the WAL when the process "dies".
mem.save(make_entry("late", &[0.0, 0.0, 0.0, 1.0])).unwrap();
drop(mem);
let mut reopened = HDF5Memory::open(&path).unwrap();
assert!(!reopened.hnsw_dirty);
assert_eq!(reopened.hnsw.as_ref().unwrap().len(), 41);
assert_eq!(top_ids(&mut reopened, &[0.0, 0.0, 0.0, 1.0])[0], 40);
}
#[cfg(feature = "hnsw")]
#[test]
fn replayed_update_invalidates_the_saved_index() {
let dir = TempDir::new().unwrap();
let (mut mem, path) = indexed_store(&dir, 40);
top_ids(&mut mem, &[1.0, 0.0, 0.0, 0.0]);
mem.flush_wal().unwrap();
// An in-place update after the checkpoint changes record 0's vector;
// the saved graph was built over the old one.
let mut moved = make_entry("rec0 moved", &[0.0, 0.0, 0.0, 1.0]);
moved.tags = mem.cache.tags[0].clone();
mem.save_or_update(moved).unwrap();
let expected = top_ids(&mut mem, &[0.0, 0.0, 0.0, 1.0]);
std::mem::forget(mem); // die without the drop-time checkpoint
let mut reopened = HDF5Memory::open_read_only(&path).unwrap();
assert!(reopened.hnsw_dirty, "saved index must not be reused");
assert_eq!(top_ids(&mut reopened, &[0.0, 0.0, 0.0, 1.0]), expected);
}
#[cfg(feature = "hnsw")]
#[test]
fn stale_or_damaged_index_sidecar_is_ignored() {
let dir = TempDir::new().unwrap();
let (mut mem, path) = indexed_store(&dir, 40);
let q = [1.0, 0.0, 0.0, 0.0];
top_ids(&mut mem, &q); // builds the index
mem.flush_wal().unwrap();
let ann = HDF5Memory::vector_index_path(&path);
let first_sidecar = std::fs::read(&ann).unwrap();
// A second checkpoint gets a new generation.
mem.save(make_entry("more", &[0.5, 0.5, 0.0, 0.0])).unwrap();
top_ids(&mut mem, &q);
mem.flush_wal().unwrap();
let expected_after = top_ids(&mut mem, &q);
drop(mem);
// Sidecar from the earlier checkpoint: wrong generation.
std::fs::write(&ann, &first_sidecar).unwrap();
let mut reopened = HDF5Memory::open_read_only(&path).unwrap();
assert!(reopened.hnsw_dirty);
assert_eq!(top_ids(&mut reopened, &q), expected_after);
drop(reopened);
// Right generation, damaged graph.
let mut mem = HDF5Memory::open(&path).unwrap();
top_ids(&mut mem, &q);
mem.flush_wal().unwrap();
drop(mem);
let mut bytes = std::fs::read(&ann).unwrap();
let mid = bytes.len() / 2;
bytes[mid] ^= 0xFF;
std::fs::write(&ann, &bytes).unwrap();
let mut reopened = HDF5Memory::open_read_only(&path).unwrap();
assert!(reopened.hnsw_dirty);
assert_eq!(top_ids(&mut reopened, &q), expected_after);
}
#[test]
fn keyword_index_stays_in_sync_through_every_mutation() {
let dir = TempDir::new().unwrap();
let mut config = make_config(&dir);
config.compact_threshold = 0.0; // compact only when asked
let mut mem = HDF5Memory::create(config).unwrap();
let check = |mem: &mut HDF5Memory, what: &str| {
let fresh = bm25::BM25Index::build(&mem.cache.chunks, &mem.cache.tombstones);
let n = mem.cache.len();
for query in ["apple", "banana cherry", "date", "nothing"] {
let kept = mem.ensure_bm25_fresh().search(query, n);
assert_eq!(kept, fresh.search(query, n), "{what}: {query:?}");
}
};
let tagged = |chunk: &str, tag: &str| {
let mut e = make_entry(chunk, &[1.0, 0.0, 0.0, 0.0]);
e.tags = tag.into();
e
};
check(&mut mem, "empty");
mem.save(tagged("apple banana", "a")).unwrap();
mem.save(tagged("banana cherry cherry", "b")).unwrap();
check(&mut mem, "after saves");
mem.save_batch(vec![tagged("date apple", "c"), tagged("cherry", "d")])
.unwrap();
check(&mut mem, "after save_batch");
mem.save_or_update(tagged("date date date", "a")).unwrap();
check(&mut mem, "after in-place update");
mem.delete(1).unwrap();
check(&mut mem, "after delete");
mem.save(tagged("apple cherry", "e")).unwrap();
check(&mut mem, "after save following a delete");
mem.compact().unwrap();
check(&mut mem, "after compact");
mem.hybrid_search(&[1.0, 0.0, 0.0, 0.0], "apple", 0.5, 0.5, 3);
check(&mut mem, "after a search");
}
#[test]
fn search_does_not_write_the_store_but_boosts_persist_on_drop() {
let dir = TempDir::new().unwrap();
let config = make_config(&dir);
let path = config.path.clone();
let mut mem = HDF5Memory::create(config).unwrap();
mem.save(make_entry("findable", &[1.0, 0.0, 0.0, 0.0]))
.unwrap();
let before = std::fs::read(&path).unwrap();
for _ in 0..3 {
mem.hybrid_search(&[1.0, 0.0, 0.0, 0.0], "findable", 1.0, 0.0, 1);
}
assert_eq!(
std::fs::read(&path).unwrap(),
before,
"a query must not rewrite the store"
);
let boosted = mem.cache.activation_weights[0];
assert!(boosted > 1.0);
drop(mem);
let reopened = HDF5Memory::open(&path).unwrap();
assert_eq!(reopened.cache.activation_weights[0], boosted);
}
#[test]
fn activation_weight_is_capped() {
let dir = TempDir::new().unwrap();
let mut mem = HDF5Memory::create(make_config(&dir)).unwrap();
mem.save(make_entry("popular", &[1.0, 0.0, 0.0, 0.0]))
.unwrap();
for _ in 0..500 {
mem.hybrid_search(&[1.0, 0.0, 0.0, 0.0], "popular", 1.0, 0.0, 1);
}
assert_eq!(mem.cache.activation_weights[0], MAX_ACTIVATION_WEIGHT);
}
#[test]
fn store_has_a_single_writer() {
let dir = TempDir::new().unwrap();
+50
View File
@@ -22,6 +22,7 @@ pub const ZEROCLAW_VERSION: &str = "0.8.0";
/// the checkpoint was taken with an empty WAL.
const WAL_APPLIED_LEN_ATTR: &str = "wal_applied_len";
const WAL_APPLIED_CRC_ATTR: &str = "wal_applied_crc";
const ANN_GENERATION_ATTR: &str = "ann_generation";
/// Build a complete HDF5 file from the in-memory state.
pub fn build_hdf5_file(
@@ -43,6 +44,34 @@ pub fn build_hdf5_file_with_mark(
knowledge: &KnowledgeCache,
wal_applied: Option<WalMark>,
) -> Result<Vec<u8>, MemoryError> {
let meta = CheckpointMeta {
wal_applied,
ann_generation: None,
};
build_hdf5_file_with_meta(config, cache, sessions, knowledge, &meta)
}
/// Bookkeeping a checkpoint records in `/meta` beside the store's contents.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
pub struct CheckpointMeta {
/// The WAL prefix this checkpoint already contains; see [`WalMark`].
pub wal_applied: Option<WalMark>,
/// Identifies the vector-index sidecar (`<store>.h5.ann`) written with this
/// checkpoint. A sidecar is loaded only if it carries the same value, so
/// one left over from another checkpoint can never be attached to records
/// it wasn't built from.
pub ann_generation: Option<u64>,
}
/// [`build_hdf5_file`] with checkpoint bookkeeping.
pub fn build_hdf5_file_with_meta(
config: &MemoryConfig,
cache: &MemoryCache,
sessions: &SessionCache,
knowledge: &KnowledgeCache,
checkpoint: &CheckpointMeta,
) -> Result<Vec<u8>, MemoryError> {
let wal_applied = checkpoint.wal_applied;
let mut builder = clawhdf5::FileBuilder::new();
// /meta group with schema attributes
@@ -83,6 +112,11 @@ pub fn build_hdf5_file_with_mark(
meta.set_attr(WAL_APPLIED_LEN_ATTR, AttrValue::I64(mark.len as i64));
meta.set_attr(WAL_APPLIED_CRC_ATTR, AttrValue::I64(i64::from(mark.crc)));
}
if let Some(generation) = checkpoint.ann_generation {
// Stored as the i64 with the same bits; attributes have no u64 scalar
// round trip through every reader.
meta.set_attr(ANN_GENERATION_ATTR, AttrValue::I64(generation as i64));
}
// Need at least one dataset in the group for it to be a proper group
meta.create_dataset("_marker").with_u8_data(&[1]).compact();
let finished_meta = meta.finish();
@@ -386,6 +420,22 @@ pub fn read_wal_mark(file: &clawhdf5::File) -> Option<WalMark> {
Some(WalMark { len, crc })
}
/// Read the checkpoint bookkeeping from `/meta`.
pub fn read_checkpoint_meta(file: &clawhdf5::File) -> CheckpointMeta {
let ann_generation = file
.group("meta")
.ok()
.and_then(|g| g.attrs().ok())
.and_then(|attrs| match attrs.get(ANN_GENERATION_ATTR) {
Some(AttrValue::I64(v)) => Some(*v as u64),
_ => None,
});
CheckpointMeta {
wal_applied: read_wal_mark(file),
ann_generation,
}
}
pub fn validate_and_load(
file: &clawhdf5::File,
) -> Result<(MemoryConfig, MemoryCache, SessionCache, KnowledgeCache), MemoryError> {
+20 -5
View File
@@ -4,7 +4,7 @@ use std::path::Path;
use crate::bm25;
use crate::hybrid;
use crate::{HDF5Memory, MemoryError, Result, SearchResult};
use crate::{HDF5Memory, MAX_ACTIVATION_WEIGHT, MemoryError, Result, SearchResult};
impl HDF5Memory {
/// Vector + keyword scoring stage of [`HDF5Memory::hybrid_search`].
@@ -90,7 +90,11 @@ impl HDF5Memory {
keyword_weight: f32,
k: usize,
) -> Vec<SearchResult> {
let bm25 = bm25::BM25Index::build(&self.cache.chunks, &self.cache.tombstones);
// The keyword index lives for the life of the store and is updated
// incrementally. Take it out for the duration of the call so the
// vector stage can borrow `self` mutably, then put it back.
self.ensure_bm25_fresh();
let bm25 = self.bm25.take().expect("ensure_bm25_fresh leaves an index");
let scored = self.vector_keyword_search(
query_embedding,
query_text,
@@ -132,15 +136,26 @@ impl HDF5Memory {
.map(|r| r.index)
.collect();
self.apply_hebbian_boost(&hit_indices);
self.flush().ok();
self.bm25 = Some(bm25);
results
}
/// Reinforce the records a query returned. The new weights are persisted by
/// the next checkpoint (any write that flushes, `flush_wal`, or drop) — not
/// by rewriting the whole store inside the query, which is what made
/// `hybrid_search` cost O(store size) in disk I/O. They are a ranking hint,
/// not user data: a crash before the next checkpoint only forgets the
/// boosts since the last one.
fn apply_hebbian_boost(&mut self, hit_indices: &[usize]) {
for &idx in hit_indices {
self.cache.activation_weights[idx] += self.config.hebbian_boost;
if hit_indices.is_empty() || self.config.hebbian_boost == 0.0 {
return;
}
for &idx in hit_indices {
let w = &mut self.cache.activation_weights[idx];
*w = (*w + self.config.hebbian_boost).min(MAX_ACTIVATION_WEIGHT);
}
self.activations_dirty = true;
}
/// Get the chunk text for a memory entry by index.
+33 -3
View File
@@ -34,7 +34,23 @@ pub fn write_to_disk_with_mark(
knowledge: &KnowledgeCache,
wal_applied: Option<WalMark>,
) -> Result<(), MemoryError> {
let bytes = schema::build_hdf5_file_with_mark(config, cache, sessions, knowledge, wal_applied)?;
let meta = schema::CheckpointMeta {
wal_applied,
ann_generation: None,
};
write_to_disk_with_meta(path, config, cache, sessions, knowledge, &meta)
}
/// [`write_to_disk`] with full checkpoint bookkeeping.
pub fn write_to_disk_with_meta(
path: &Path,
config: &MemoryConfig,
cache: &MemoryCache,
sessions: &SessionCache,
knowledge: &KnowledgeCache,
checkpoint: &schema::CheckpointMeta,
) -> Result<(), MemoryError> {
let bytes = schema::build_hdf5_file_with_meta(config, cache, sessions, knowledge, checkpoint)?;
if bytes.is_empty() {
return Err(MemoryError::Hdf5("build_hdf5_file produced 0 bytes".into()));
@@ -47,7 +63,7 @@ pub fn write_to_disk_with_mark(
}
/// Write `bytes` to `path` and flush them to stable storage.
fn write_synced(path: &Path, bytes: &[u8]) -> Result<(), MemoryError> {
pub(crate) fn write_synced(path: &Path, bytes: &[u8]) -> Result<(), MemoryError> {
use std::io::Write;
let mut f = std::fs::File::create(path).map_err(MemoryError::Io)?;
f.write_all(bytes).map_err(MemoryError::Io)?;
@@ -62,7 +78,7 @@ fn write_synced(path: &Path, bytes: &[u8]) -> Result<(), MemoryError> {
/// This is per-checkpoint/snapshot cost only (each is already a full file
/// write). Individual WAL appends are deliberately not synced — see the
/// durability notes in the crate docs.
fn rename_synced(from: &Path, to: &Path) -> Result<(), MemoryError> {
pub(crate) fn rename_synced(from: &Path, to: &Path) -> Result<(), MemoryError> {
std::fs::rename(from, to).map_err(MemoryError::Io)?;
#[cfg(unix)]
if let Some(dir) = to.parent() {
@@ -113,6 +129,20 @@ pub fn read_from_disk_with_mark(path: &Path) -> Result<(StoreState, Option<WalMa
Ok(((config, cache, sessions, knowledge), wal_applied))
}
/// [`read_from_disk`], plus all checkpoint bookkeeping.
pub fn read_from_disk_with_meta(
path: &Path,
) -> Result<(StoreState, schema::CheckpointMeta), MemoryError> {
let mmap = clawhdf5_io::MmapReader::open(path).map_err(MemoryError::Io)?;
mmap.advise_willneed(0, mmap.len());
let file = clawhdf5::File::from_bytes(mmap.as_bytes().to_vec())
.map_err(|e| MemoryError::Hdf5(format!("cannot open {}: {e}", path.display())))?;
let (mut config, cache, sessions, knowledge) = schema::validate_and_load(&file)?;
config.path = path.to_path_buf();
let meta = schema::read_checkpoint_meta(&file);
Ok(((config, cache, sessions, knowledge), meta))
}
/// Copy an HDF5 file atomically to a destination.
pub fn snapshot_file(src: &Path, dest: &Path) -> Result<std::path::PathBuf, MemoryError> {
let dest_file = if dest.is_dir() {
+375 -16
View File
@@ -134,6 +134,9 @@ impl Ord for FarCandidate {
}
}
/// Magic for [`HnswIndex::graph_to_bytes`].
const GRAPH_MAGIC: &[u8; 4] = b"CHG1";
/// On-disk format version for the serialized HNSW index.
///
/// - Version 1: original layout (`vectors`, `graph_layer_*`, `config`), no
@@ -252,8 +255,9 @@ impl HnswIndex {
metric,
);
// Select up to m closest neighbors
let selected: Vec<usize> = neighbors.iter().take(max_conn).map(|c| c.id).collect();
let scored: Vec<(usize, f32)> =
neighbors.iter().map(|c| (c.id, c.distance)).collect();
let selected = select_neighbors(vectors, &scored, max_conn, metric);
// Add bidirectional connections
graph[layer][i] = selected.clone();
@@ -382,7 +386,8 @@ impl HnswIndex {
self.ef_construction,
self.metric,
);
let selected: Vec<usize> = neighbors.iter().take(max_conn).map(|c| c.id).collect();
let scored: Vec<(usize, f32)> = neighbors.iter().map(|c| (c.id, c.distance)).collect();
let selected = select_neighbors(&self.vectors, &scored, max_conn, self.metric);
self.graph[layer][id] = selected.clone();
for &neighbor in &selected {
self.graph[layer][neighbor].push(id);
@@ -688,6 +693,160 @@ impl HnswIndex {
})
}
/// Serialize the **graph only** — levels, tombstones and adjacency, not the
/// vectors — for a caller that already stores the vectors elsewhere (the
/// agent's record cache). [`HnswIndex::to_hdf5_bytes`] writes a complete,
/// self-contained index including a full copy of every vector, which would
/// double such a store's size. Reattach with
/// [`HnswIndex::from_graph_bytes`].
///
/// Layout (little endian): magic `CHG1`, then u32 fields `n`, `m`,
/// `m_max0`, `ef_construction`, `entry_point`, `num_layers`, `metric`;
/// `n` level bytes; `n` tombstone bytes; per layer, per node that exists on
/// that layer: u32 neighbour count + u32 ids; trailing CRC32 of all of it.
pub fn graph_to_bytes(&self) -> Vec<u8> {
let n = self.vectors.len();
let mut out = Vec::with_capacity(32 + n * 2 + n * self.m_max0 * 4);
out.extend_from_slice(GRAPH_MAGIC);
for field in [
n,
self.m,
self.m_max0,
self.ef_construction,
self.entry_point,
self.graph.len(),
match self.metric {
DistanceMetric::L2 => 0,
DistanceMetric::Cosine => 1,
},
] {
out.extend_from_slice(&(field as u32).to_le_bytes());
}
out.extend(self.node_levels.iter().map(|&l| l.min(255) as u8));
out.extend(self.deleted.iter().map(|&d| u8::from(d)));
for (layer, adjacency) in self.graph.iter().enumerate() {
for (node, neighbors) in adjacency.iter().enumerate() {
if self.node_levels[node] < layer {
continue; // node does not exist on this layer
}
out.extend_from_slice(&(neighbors.len() as u32).to_le_bytes());
for &id in neighbors {
out.extend_from_slice(&(id as u32).to_le_bytes());
}
}
}
let crc = clawhdf5_format::checksum::crc32(&out);
out.extend_from_slice(&crc.to_le_bytes());
out
}
/// Rebuild an index from [`HnswIndex::graph_to_bytes`] output and the
/// vectors it was built over (same order). Every structural claim in
/// `bytes` is validated — a corrupt or mismatched graph is an error, never
/// an index that panics or walks out of bounds during a search.
pub fn from_graph_bytes(bytes: &[u8], vectors: Vec<Vec<f32>>) -> Result<Self, FormatError> {
let bad = |what: &str| FormatError::SerializationError(format!("HNSW graph: {what}"));
let body_len = bytes
.len()
.checked_sub(4)
.filter(|&l| l >= GRAPH_MAGIC.len() + 7 * 4)
.ok_or_else(|| bad("truncated"))?;
let (body, crc_bytes) = bytes.split_at(body_len);
if &body[..4] != GRAPH_MAGIC {
return Err(bad("bad magic"));
}
let stored_crc =
u32::from_le_bytes([crc_bytes[0], crc_bytes[1], crc_bytes[2], crc_bytes[3]]);
if clawhdf5_format::checksum::crc32(body) != stored_crc {
return Err(bad("checksum mismatch"));
}
let mut pos = 4;
let next_u32 = |pos: &mut usize| -> Result<usize, FormatError> {
let b = body.get(*pos..*pos + 4).ok_or_else(|| bad("truncated"))?;
*pos += 4;
Ok(u32::from_le_bytes([b[0], b[1], b[2], b[3]]) as usize)
};
let n = next_u32(&mut pos)?;
let m = next_u32(&mut pos)?;
let m_max0 = next_u32(&mut pos)?;
let ef_construction = next_u32(&mut pos)?;
let entry_point = next_u32(&mut pos)?;
let num_layers = next_u32(&mut pos)?;
let metric = match next_u32(&mut pos)? {
0 => DistanceMetric::L2,
1 => DistanceMetric::Cosine,
_ => return Err(bad("unknown metric")),
};
if n != vectors.len() {
return Err(bad("vector count does not match the graph"));
}
if n == 0 || entry_point >= n || m < 2 || num_layers == 0 || num_layers > 256 {
return Err(bad("invalid header"));
}
let dim = vectors[0].len();
if vectors.iter().any(|v| v.len() != dim) {
return Err(bad("vectors have mixed dimensions"));
}
let levels = body.get(pos..pos + n).ok_or_else(|| bad("truncated"))?;
pos += n;
let node_levels: Vec<usize> = levels.iter().map(|&l| l as usize).collect();
if node_levels.iter().any(|&l| l >= num_layers)
|| node_levels[entry_point] + 1 != num_layers
{
return Err(bad("levels inconsistent with layer count"));
}
let deleted: Vec<bool> = body
.get(pos..pos + n)
.ok_or_else(|| bad("truncated"))?
.iter()
.map(|&d| d != 0)
.collect();
pos += n;
let mut graph: Vec<Vec<Vec<usize>>> = Vec::with_capacity(num_layers);
for layer in 0..num_layers {
let max_conn = if layer == 0 { m_max0 } else { m };
let mut adjacency = vec![Vec::new(); n];
for (node, slot) in adjacency.iter_mut().enumerate() {
if node_levels[node] < layer {
continue;
}
let count = next_u32(&mut pos)?;
if count > max_conn {
return Err(bad("neighbour list exceeds the connection limit"));
}
let mut neighbors = Vec::with_capacity(count);
for _ in 0..count {
let id = next_u32(&mut pos)?;
// A neighbour must exist, and exist on this layer.
if id >= n || node_levels[id] < layer {
return Err(bad("neighbour id out of range for its layer"));
}
neighbors.push(id);
}
*slot = neighbors;
}
graph.push(adjacency);
}
if pos != body.len() {
return Err(bad("trailing bytes"));
}
Ok(Self {
vectors,
graph,
deleted,
entry_point,
m,
m_max0,
ef_construction,
node_levels,
metric,
})
}
/// Returns the number of vectors in the index.
pub fn len(&self) -> usize {
self.vectors.len()
@@ -828,7 +987,52 @@ fn search_layer(
result
}
/// Prune connections for a node to keep only the closest `max_conn` neighbors.
/// Choose up to `max_conn` neighbours for a node from `candidates` (sorted by
/// ascending distance to that node) — the HNSW paper's Algorithm 4 with
/// `keepPrunedConnections`.
///
/// Taking the plain `max_conn` closest is what breaks the graph on clustered
/// data: every link of a node inside a tight cluster goes to that same cluster,
/// so clusters become islands that a search entering elsewhere can never
/// reach, however large `ef` is. Instead a candidate is accepted only if it is
/// closer to the node than to every neighbour already accepted, which spreads
/// links across directions and keeps the long edges that join clusters. Any
/// remaining slots are then filled with the closest rejected candidates, so a
/// node is never left under-connected.
fn select_neighbors(
vectors: &[Vec<f32>],
candidates: &[(usize, f32)],
max_conn: usize,
metric: DistanceMetric,
) -> Vec<usize> {
if candidates.len() <= max_conn {
return candidates.iter().map(|&(id, _)| id).collect();
}
let mut selected: Vec<usize> = Vec::with_capacity(max_conn);
let mut rejected: Vec<usize> = Vec::new();
for &(id, dist_to_node) in candidates {
if selected.len() >= max_conn {
break;
}
let diverse = selected
.iter()
.all(|&s| compute_distance(&vectors[id], &vectors[s], metric) > dist_to_node);
if diverse {
selected.push(id);
} else {
rejected.push(id);
}
}
for id in rejected {
if selected.len() >= max_conn {
break;
}
selected.push(id);
}
selected
}
/// Trim `node`'s neighbour list back to `max_conn` with [`select_neighbors`].
fn prune_connections(
vectors: &[Vec<f32>],
neighbors: &mut Vec<usize>,
@@ -839,22 +1043,12 @@ fn prune_connections(
if neighbors.len() <= max_conn {
return;
}
#[cfg(feature = "parallel")]
let mut scored: Vec<(usize, f32)> = {
use rayon::prelude::*;
neighbors
.par_iter()
.map(|&n| (n, compute_distance(&vectors[node], &vectors[n], metric)))
.collect()
};
#[cfg(not(feature = "parallel"))]
let mut scored: Vec<(usize, f32)> = neighbors
.iter()
.map(|&n| (n, compute_distance(&vectors[node], &vectors[n], metric)))
.collect();
scored.sort_by(|a, b| a.1.partial_cmp(&b.1).unwrap_or(std::cmp::Ordering::Equal));
scored.truncate(max_conn);
*neighbors = scored.into_iter().map(|(id, _)| id).collect();
scored.sort_by(|a, b| a.1.total_cmp(&b.1).then(a.0.cmp(&b.0)));
*neighbors = select_neighbors(vectors, &scored, max_conn, metric);
}
// ---------------------------------------------------------------------------
@@ -1043,6 +1237,171 @@ fn get_attr_string(attrs: &[(String, AttrValue)], name: &str) -> Result<String,
mod tests {
use super::*;
/// Tight, well-separated clusters — the shape real embeddings have, and
/// the case plain closest-M neighbour selection fails on: each cluster
/// becomes an island, so recall is capped no matter how large `ef` is.
fn clustered(n: usize, dim: usize, clusters: usize, seed: u64) -> Vec<Vec<f32>> {
let mut state = seed;
let mut next = move || {
state = state.wrapping_add(0x9E37_79B9_7F4A_7C15);
let mut z = state;
z = (z ^ (z >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
z = (z ^ (z >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
((z ^ (z >> 31)) >> 40) as f32 / (1u64 << 24) as f32 - 0.5
};
let centres: Vec<Vec<f32>> = (0..clusters)
.map(|_| (0..dim).map(|_| next() * 10.0).collect())
.collect();
(0..n)
.map(|i| {
centres[i % clusters]
.iter()
.map(|c| c + next() * 0.5)
.collect()
})
.collect()
}
fn recall_at_10(
index: &HnswIndex,
vectors: &[Vec<f32>],
queries: &[Vec<f32>],
ef: usize,
) -> f64 {
let mut hits = 0;
for q in queries {
let mut exact: Vec<(usize, f32)> = vectors
.iter()
.enumerate()
.map(|(i, v)| (i, compute_distance(q, v, DistanceMetric::L2)))
.collect();
exact.sort_by(|a, b| a.1.total_cmp(&b.1));
let want: Vec<usize> = exact[..10].iter().map(|e| e.0).collect();
hits += index
.search(q, 10, ef)
.iter()
.filter(|(id, _)| want.contains(id))
.count();
}
hits as f64 / (10 * queries.len()) as f64
}
#[test]
fn clustered_data_keeps_high_recall() {
// Data and queries come from the same clusters: one draw, split.
let mut vectors = clustered(3060, 24, 30, 1);
let queries = vectors.split_off(3000);
let built = HnswIndex::build_with_metric(&vectors, 8, 40, DistanceMetric::L2);
let recall = recall_at_10(&built, &vectors, &queries, 64);
assert!(recall >= 0.95, "bulk build recall@10 = {recall}");
// Incremental inserts go through the same neighbour selection.
let mut incremental = HnswIndex::new(8, 40, DistanceMetric::L2);
for v in &vectors {
incremental.insert(v.clone());
}
let recall = recall_at_10(&incremental, &vectors, &queries, 64);
assert!(recall >= 0.95, "incremental recall@10 = {recall}");
}
#[test]
fn graph_bytes_round_trip_gives_identical_searches() {
let mut vectors = clustered(1260, 16, 12, 9);
let queries = vectors.split_off(1200);
let mut index = HnswIndex::build_with_metric(&vectors, 8, 40, DistanceMetric::L2);
index.mark_deleted(3);
index.mark_deleted(700);
let bytes = index.graph_to_bytes();
// The graph is a small fraction of the vectors it indexes... not
// necessarily at dim 16, but it must not embed them.
assert!(bytes.len() < 1200 * (16 * 2 + 2) * 4);
let restored = HnswIndex::from_graph_bytes(&bytes, vectors.clone()).unwrap();
assert_eq!(restored.deleted_count(), 2);
for q in &queries {
assert_eq!(restored.search(q, 10, 50), index.search(q, 10, 50));
}
// A restored index keeps working incrementally.
let mut restored = restored;
let id = restored.insert(queries[0].clone());
assert_eq!(restored.search(&queries[0], 1, 50)[0].0, id);
}
#[test]
fn damaged_or_mismatched_graph_bytes_are_errors() {
let vectors = clustered(300, 8, 6, 4);
let index = HnswIndex::build_with_metric(&vectors, 6, 30, DistanceMetric::Cosine);
let bytes = index.graph_to_bytes();
// Wrong vector set.
assert!(HnswIndex::from_graph_bytes(&bytes, vectors[..299].to_vec()).is_err());
// Every truncation.
for len in 0..bytes.len() {
assert!(
HnswIndex::from_graph_bytes(&bytes[..len], vectors.clone()).is_err(),
"truncated to {len}"
);
}
// A flipped bit anywhere.
for i in (0..bytes.len()).step_by(7) {
let mut damaged = bytes.clone();
damaged[i] ^= 0x10;
assert!(
HnswIndex::from_graph_bytes(&damaged, vectors.clone()).is_err(),
"bit flip at {i}"
);
}
}
#[test]
fn structurally_invalid_graph_with_a_valid_checksum_is_rejected() {
// The CRC only proves the bytes are what was written; a hostile or
// buggy writer can checksum nonsense. Out-of-range neighbour ids must
// still be caught, or search would index out of bounds.
let vectors = clustered(50, 4, 3, 5);
let index = HnswIndex::build_with_metric(&vectors, 4, 20, DistanceMetric::L2);
let mut bytes = index.graph_to_bytes();
let body_len = bytes.len() - 4;
// First neighbour id of node 0 on layer 0 sits right after the header,
// levels, tombstones and node 0's count.
let at = 4 + 7 * 4 + 50 + 50 + 4;
bytes[at..at + 4].copy_from_slice(&9999u32.to_le_bytes());
let crc = clawhdf5_format::checksum::crc32(&bytes[..body_len]);
bytes[body_len..].copy_from_slice(&crc.to_le_bytes());
assert!(HnswIndex::from_graph_bytes(&bytes, vectors).is_err());
}
#[test]
fn select_neighbors_prefers_diverse_directions_and_fills_up() {
// Node at the origin. Three candidates bunched together on the right,
// one on the left. With room for two, plain closest-M would take two
// from the bunch and lose the only link leftwards.
let vectors = vec![
vec![0.0, 0.0], // 0: the node
vec![1.0, 0.0], // 1
vec![1.1, 0.0], // 2
vec![1.2, 0.0], // 3
vec![-2.0, 0.0], // 4
];
let scored: Vec<(usize, f32)> = (1..5)
.map(|i| {
(
i,
compute_distance(&vectors[0], &vectors[i], DistanceMetric::L2),
)
})
.collect();
assert_eq!(
select_neighbors(&vectors, &scored, 2, DistanceMetric::L2),
[1, 4]
);
// Spare capacity is filled with the closest rejected candidates.
assert_eq!(
select_neighbors(&vectors, &scored, 3, DistanceMetric::L2),
[1, 4, 2]
);
}
fn make_random_vectors(n: usize, dim: usize, seed: u64) -> Vec<Vec<f32>> {
let mut vectors = Vec::with_capacity(n);
let mut state = seed;
+5
View File
@@ -13,6 +13,10 @@ path = "src/bin/longmemeval_bench.rs"
name = "memory_arena"
path = "src/bin/memory_arena.rs"
[[bin]]
name = "search_harness"
path = "src/bin/search_harness.rs"
[[bin]]
name = "footprint_bench"
path = "src/bin/footprint_bench.rs"
@@ -48,6 +52,7 @@ harness = false
[dependencies]
clawhdf5-agent = { path = "../clawhdf5-agent" }
clawhdf5-ann = { path = "../clawhdf5-ann" }
clawhdf5-io = { path = "../clawhdf5-io" }
mpi = { version = "0.8", optional = true }
serde = { workspace = true }
@@ -0,0 +1,417 @@
//! Search measurement harness: recall vs. speed for the HNSW index, and
//! end-to-end `hybrid_search` latency as the store grows.
//!
//! Every search-path change should be justified by a before/after run of this
//! binary. It reports, for deterministic synthetic data:
//!
//! * **ANN** — index build time, and for each `ef`: recall@10 against an exact
//! brute-force scan, queries/second, and p50/p99 latency.
//! * **End to end** — `HDF5Memory`: ingest time, checkpoint time, `open()`
//! time, the one-off cold index build (first query ever), the first query
//! after a reopen, and steady-state `hybrid_search` p50/p99 at each size.
//!
//! Data is *clustered* (points = cluster centre + noise, unit-normalised), not
//! uniform: uniform random high-dimensional vectors are nearly equidistant,
//! which makes recall numbers meaningless and is nothing like embeddings.
//!
//! ```text
//! cargo run --release -p clawhdf5-bench --bin search_harness # 1K, 10K
//! cargo run --release -p clawhdf5-bench --bin search_harness -- --full # + 100K
//! cargo run --release -p clawhdf5-bench --bin search_harness -- --json out.json
//! cargo run --release -p clawhdf5-bench --bin search_harness -- --ann-only --uniform
//! ```
use std::time::{Duration, Instant};
use clawhdf5_agent::{AgentMemory, HDF5Memory, MemoryConfig, MemoryEntry};
use clawhdf5_ann::{DistanceMetric, HnswIndex};
const DIM: usize = 384;
const K: usize = 10;
const N_QUERIES: usize = 200;
const HNSW_M: usize = 16;
const HNSW_EF_CONSTRUCTION: usize = 64;
const EF_VALUES: [usize; 5] = [16, 32, 64, 128, 256];
// ---------------------------------------------------------------------------
// Deterministic data
// ---------------------------------------------------------------------------
struct Rng(u64);
impl Rng {
fn next_u64(&mut self) -> u64 {
self.0 = self.0.wrapping_add(0x9E37_79B9_7F4A_7C15);
let mut z = self.0;
z = (z ^ (z >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
z = (z ^ (z >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
z ^ (z >> 31)
}
/// Uniform in [0, 1).
fn unit(&mut self) -> f32 {
(self.next_u64() >> 40) as f32 / (1u64 << 24) as f32
}
/// Approximately standard normal (sum of uniforms).
fn gauss(&mut self) -> f32 {
let sum: f32 = (0..6).map(|_| self.unit()).sum();
(sum - 3.0) * std::f32::consts::SQRT_2
}
fn below(&mut self, n: usize) -> usize {
(self.next_u64() % n as u64) as usize
}
}
fn normalize(v: &mut [f32]) {
let norm = v.iter().map(|x| x * x).sum::<f32>().sqrt();
if norm > 0.0 {
v.iter_mut().for_each(|x| *x /= norm);
}
}
struct Dataset {
vectors: Vec<Vec<f32>>,
queries: Vec<Vec<f32>>,
/// Cluster id of each vector (used to give records topical text).
cluster_of: Vec<usize>,
query_cluster: Vec<usize>,
}
/// `--uniform`: isotropic random unit vectors instead of clusters. Not a
/// realistic workload, but a useful second distribution — a recall problem
/// that appears only on clustered data points at graph connectivity.
static UNIFORM: std::sync::atomic::AtomicBool = std::sync::atomic::AtomicBool::new(false);
fn make_dataset(n: usize, seed: u64) -> Dataset {
let mut rng = Rng(seed);
if UNIFORM.load(std::sync::atomic::Ordering::Relaxed) {
let random_unit = |rng: &mut Rng| {
let mut v: Vec<f32> = (0..DIM).map(|_| rng.gauss()).collect();
normalize(&mut v);
v
};
return Dataset {
vectors: (0..n).map(|_| random_unit(&mut rng)).collect(),
queries: (0..N_QUERIES).map(|_| random_unit(&mut rng)).collect(),
cluster_of: vec![0; n],
query_cluster: vec![0; N_QUERIES],
};
}
let n_clusters = (n / 100).clamp(8, 512);
let centres: Vec<Vec<f32>> = (0..n_clusters)
.map(|_| {
let mut c: Vec<f32> = (0..DIM).map(|_| rng.gauss()).collect();
normalize(&mut c);
c
})
.collect();
let point = |rng: &mut Rng, cluster: usize| {
// Noise comparable to the centre's per-dimension magnitude, so
// clusters overlap and the nearest neighbours are non-trivial.
let scale = 0.6 / (DIM as f32).sqrt();
let mut v: Vec<f32> = centres[cluster]
.iter()
.map(|c| c + rng.gauss() * scale)
.collect();
normalize(&mut v);
v
};
let mut vectors = Vec::with_capacity(n);
let mut cluster_of = Vec::with_capacity(n);
for _ in 0..n {
let c = rng.below(n_clusters);
vectors.push(point(&mut rng, c));
cluster_of.push(c);
}
let mut queries = Vec::with_capacity(N_QUERIES);
let mut query_cluster = Vec::with_capacity(N_QUERIES);
for _ in 0..N_QUERIES {
let c = rng.below(n_clusters);
queries.push(point(&mut rng, c));
query_cluster.push(c);
}
Dataset {
vectors,
queries,
cluster_of,
query_cluster,
}
}
const WORDS: &[&str] = &[
"deploy", "latency", "cache", "schema", "index", "vector", "memory", "agent", "kernel",
"buffer", "socket", "thread", "tensor", "gradient", "ledger", "invoice", "meeting", "roadmap",
"customer", "contract", "sensor", "orbit", "protein", "genome", "harbor", "bridge", "engine",
"battery", "harvest", "weather", "museum", "recipe",
];
/// Text whose vocabulary is biased by cluster, so keyword and vector signals
/// agree the way they do for real embedded text.
fn text_for(cluster: usize, i: usize, rng: &mut Rng) -> String {
let topic = [
WORDS[cluster % WORDS.len()],
WORDS[(cluster / 7 + 3) % WORDS.len()],
];
let mut words = Vec::with_capacity(14);
for j in 0..14 {
if j % 3 == 0 {
words.push(topic[j / 3 % 2]);
} else {
words.push(WORDS[rng.below(WORDS.len())]);
}
}
format!("record {i}: {}", words.join(" "))
}
// ---------------------------------------------------------------------------
// Measurement helpers
// ---------------------------------------------------------------------------
fn exact_top_k(vectors: &[Vec<f32>], query: &[f32], k: usize) -> Vec<usize> {
// Vectors are unit length, so cosine order == dot-product order.
let mut scored: Vec<(usize, f32)> = vectors
.iter()
.enumerate()
.map(|(i, v)| (i, v.iter().zip(query).map(|(a, b)| a * b).sum()))
.collect();
scored.sort_by(|a, b| b.1.total_cmp(&a.1).then(a.0.cmp(&b.0)));
scored.truncate(k);
scored.into_iter().map(|(i, _)| i).collect()
}
struct Latency {
p50: Duration,
p99: Duration,
qps: f64,
}
fn summarize(mut samples: Vec<Duration>) -> Latency {
samples.sort();
let total: Duration = samples.iter().sum();
let at = |q: f64| samples[((samples.len() - 1) as f64 * q).round() as usize];
Latency {
p50: at(0.50),
p99: at(0.99),
qps: samples.len() as f64 / total.as_secs_f64(),
}
}
fn micros(d: Duration) -> f64 {
d.as_secs_f64() * 1e6
}
fn millis(d: Duration) -> f64 {
d.as_secs_f64() * 1e3
}
// ---------------------------------------------------------------------------
// ANN: recall vs speed
// ---------------------------------------------------------------------------
fn bench_ann(n: usize, json: &mut Vec<serde_json::Value>) {
let data = make_dataset(n, 0xA11CE ^ n as u64);
let truth: Vec<Vec<usize>> = data
.queries
.iter()
.map(|q| exact_top_k(&data.vectors, q, K))
.collect();
let started = Instant::now();
let index = HnswIndex::build_with_metric(
&data.vectors,
HNSW_M,
HNSW_EF_CONSTRUCTION,
DistanceMetric::Cosine,
);
let build = started.elapsed();
// Exact scan baseline, for scale.
let exact = summarize(
data.queries
.iter()
.map(|q| {
let t = Instant::now();
std::hint::black_box(exact_top_k(&data.vectors, q, K));
t.elapsed()
})
.collect(),
);
println!(
"\n### HNSW, N = {n}, dim = {DIM}, M = {HNSW_M}, ef_construction = {HNSW_EF_CONSTRUCTION}\n"
);
println!(
"build: {:.1} ms ({:.0} vectors/s) · exact scan: {:.0} QPS, p50 {:.0} µs\n",
millis(build),
n as f64 / build.as_secs_f64(),
exact.qps,
micros(exact.p50)
);
println!("| ef | recall@{K} | QPS | p50 µs | p99 µs |");
println!("|---:|---:|---:|---:|---:|");
for ef in EF_VALUES {
let mut hits = 0usize;
let mut samples = Vec::with_capacity(data.queries.len());
for (q, want) in data.queries.iter().zip(&truth) {
let t = Instant::now();
let got = index.search(q, K, ef);
samples.push(t.elapsed());
hits += got.iter().filter(|(id, _)| want.contains(id)).count();
}
let recall = hits as f64 / (K * data.queries.len()) as f64;
let lat = summarize(samples);
println!(
"| {ef} | {recall:.4} | {:.0} | {:.0} | {:.0} |",
lat.qps,
micros(lat.p50),
micros(lat.p99)
);
json.push(serde_json::json!({
"bench": "hnsw", "n": n, "ef": ef, "recall_at_10": recall,
"qps": lat.qps, "p50_us": micros(lat.p50), "p99_us": micros(lat.p99),
"build_ms": millis(build),
}));
}
}
// ---------------------------------------------------------------------------
// End to end: HDF5Memory::hybrid_search
// ---------------------------------------------------------------------------
fn bench_end_to_end(n: usize, json: &mut Vec<serde_json::Value>) {
let data = make_dataset(n, 0xE2E ^ n as u64);
let dir = tempfile::TempDir::new().unwrap();
let path = dir.path().join("store.h5");
let mut rng = Rng(7);
let entries: Vec<MemoryEntry> = data
.vectors
.iter()
.enumerate()
.map(|(i, v)| MemoryEntry {
chunk: text_for(data.cluster_of[i], i, &mut rng),
embedding: v.clone(),
source_channel: "bench".into(),
timestamp: i as f64,
session_id: format!("s{}", i % 50),
tags: format!("t{i}"),
})
.collect();
let query_texts: Vec<String> = data
.query_cluster
.iter()
.enumerate()
.map(|(i, c)| text_for(*c, i, &mut rng))
.collect();
let mut mem = HDF5Memory::create(MemoryConfig::new(path.clone(), "bench", DIM)).unwrap();
let t = Instant::now();
mem.save_batch(entries).unwrap();
let ingest = t.elapsed();
// The very first query builds the vector and keyword indexes from
// scratch. It happens once per store, not once per session: the checkpoint
// below saves the vector index, so a later `open()` reloads it.
let t = Instant::now();
std::hint::black_box(mem.hybrid_search(&data.queries[1], &query_texts[1], 0.7, 0.3, K));
let cold_build = t.elapsed();
let t = Instant::now();
mem.flush_wal().unwrap();
let checkpoint = t.elapsed();
drop(mem);
let t = Instant::now();
let mut mem = HDF5Memory::open(&path).unwrap();
let open = t.elapsed();
// The first query after open pays for whatever is rebuilt lazily.
let t = Instant::now();
std::hint::black_box(mem.hybrid_search(&data.queries[0], &query_texts[0], 0.7, 0.3, K));
let first_query = t.elapsed();
// Fewer steady-state samples at large N: each query is currently O(N).
let samples_wanted = if n >= 100_000 { 20 } else { N_QUERIES.min(100) };
let steady = summarize(
(0..samples_wanted)
.map(|i| {
let t = Instant::now();
std::hint::black_box(mem.hybrid_search(
&data.queries[i % N_QUERIES],
&query_texts[i % N_QUERIES],
0.7,
0.3,
K,
));
t.elapsed()
})
.collect(),
);
println!(
"| {n} | {:.0} | {:.0} | {:.1} | {:.1} | {:.1} | {:.2} | {:.2} | {:.1} |",
millis(ingest),
millis(cold_build),
millis(checkpoint),
millis(open),
millis(first_query),
millis(steady.p50),
millis(steady.p99),
steady.qps
);
json.push(serde_json::json!({
"bench": "hybrid_search", "n": n,
"ingest_ms": millis(ingest), "cold_index_build_ms": millis(cold_build),
"checkpoint_ms": millis(checkpoint),
"open_ms": millis(open), "first_query_ms": millis(first_query),
"p50_ms": millis(steady.p50), "p99_ms": millis(steady.p99), "qps": steady.qps,
}));
}
fn main() {
let args: Vec<String> = std::env::args().skip(1).collect();
let full = args.iter().any(|a| a == "--full");
let ann_only = args.iter().any(|a| a == "--ann-only");
if args.iter().any(|a| a == "--uniform") {
UNIFORM.store(true, std::sync::atomic::Ordering::Relaxed);
println!("(uniform random data)");
}
let json_path = args
.iter()
.position(|a| a == "--json")
.and_then(|i| args.get(i + 1))
.cloned();
let sizes: &[usize] = if full {
&[1_000, 10_000, 100_000]
} else {
&[1_000, 10_000]
};
if cfg!(debug_assertions) {
eprintln!("warning: debug build — numbers are meaningless. Use --release.");
}
let mut json = Vec::new();
println!("## Search harness");
for &n in sizes {
bench_ann(n, &mut json);
}
if ann_only {
return;
}
println!("\n### End to end: `HDF5Memory::hybrid_search` (k = {K}, weights 0.7 / 0.3)\n");
println!(
"| N | ingest ms | cold index build ms | checkpoint ms | open ms | first query after open ms | p50 ms | p99 ms | QPS |"
);
println!("|---:|---:|---:|---:|---:|---:|---:|---:|---:|");
for &n in sizes {
bench_end_to_end(n, &mut json);
}
if let Some(path) = json_path {
std::fs::write(&path, serde_json::to_string_pretty(&json).unwrap()).unwrap();
eprintln!("wrote {path}");
}
}