What mnestic adds

mnestic is a maintained fork of CozoDB, continued under MPL-2.0 from upstream commit 481af05 (the last upstream commit, 2024-12-04). The query language (CozoScript) and engine semantics are unchanged unless noted here — what changed is performance, correctness, and the primitives an agentic-memory workload actually needs.

Lineage

The fork point is CozoDB main HEAD — 30 commits ahead of the published 0.7.6 crate, which means adopting mnestic already gives you several unreleased upstream fixes for free (including the stored_prefix_join correctness fix). The version was bumped to 0.8.0 to mark the fork's identity rather than 0.7.7.

Highlights by release

0.8.3 — native 3-way fused recall & BM25 full-text

• Native 3-way fused recall — hybrid_search now takes typed GraphLegs, so graph proximity fuses with the vector and keyword legs in one call. Each leg expands from seeds over a stored edge relation up to max_hops and ranks reached nodes by minimum hop distance. The fused call runs all three signals at ~41.55 ms p50, roughly 4× faster than hand-decomposing it into separate queries.
• BM25-correct full-text search — the default ::fts scorer is now Okapi BM25 (term-frequency saturation + document-length normalization), OR sums per-term contributions, and avgdl is an O(1) durable counter rather than a per-query scan. This lifted fused recall from 0.75 to 0.954. tf and tf_idf remain selectable for byte-identical upstream scoring.

→ Hybrid retrieval (RRF + MMR + graph legs)

0.8.2 — non-blocking HNSW index builds

Building an HNSW index no longer holds the base relation's write lock for the duration of the build, so concurrent reads no longer stall for minutes. The graph is built off-lock under a snapshot and bulk-published with RocksDB's SstFileWriter / IngestExternalFile.

→ Non-blocking HNSW builds

0.8.1 — one-call hybrid retrieval & faster builds

• hybrid_search runs HNSW + FTS (+ optional graph traversal), fuses with Reciprocal Rank Fusion, and optionally diversifies with MMR — in a single typed call, replacing roughly seven hand-written Datalog rules.
• HNSW index builds ~3× faster (20k × 128: 135 s → 43.6 s, measured release), with a byte-identical result.
• The C++/RocksDB bridge is now a maintained fork, mnestic-rocks, keeping the importable name cozorocks.

→ Hybrid retrieval (RRF + MMR)

0.8.0 — fixes & agentic-memory primitives

• Equality pushdown — *rel[k, ..], k == <value> now compiles to a keyed stored_prefix_join instead of a full scan (~28–29× faster single-row primary-key lookups at 5k rows, measured).
• ReciprocalRankFusion / MaximalMarginalRelevance fixed rules (aliases RRF / MMR) — the fusion and diversity primitives behind hybrid retrieval, usable directly in Datalog.
• ULID functions — rand_ulid() and ulid_timestamp() for lexicographically-sortable, time-ordered keys.
• Parser fix — identifiers that begin with a keyword literal (nullable_column, trueValue, falsey) now parse correctly.

→ Equality pushdown · ULID identifiers

Not affiliated with CozoDB

mnestic is not the official CozoDB and is not affiliated with or endorsed by its authors. All credit for the original design belongs to Ziyang Hu and the Cozo Project Authors. See License & attribution.