Cortex registers a graph:compression provider exposing `encode`/`decode`
for HNSW connection lists (delta-varint, ~4× smaller edges than the
JSON-UUID-array shape brainy has persisted since the beginning). This
wires the consumer side without changing the saveHNSWData/getHNSWData
adapter signatures.
Architecture:
- NEW ConnectionsCodec (src/hnsw/connectionsCodec.ts) — translates between
UUID-keyed Map<level, Set<UUID>> and a single compact per-node buffer
via the provider + stable EntityIdMapper. Custom wire format:
[count: u8] [[level: u8] [len: u32 LE] [bytes...]]*. One blob per node
regardless of level count, so the storage I/O is identical to the
legacy path (one saveHNSWData call) plus a single saveBinaryBlob.
- HNSWIndex changes — a `connectionsCodec: ConnectionsCodec | null` field
with `setConnectionsCodec()` setter. THREE save sites (deferred flush,
immediate-mode entity persist, immediate-mode neighbor updates) now go
through a single `persistNodeConnections(nodeId, noun)` helper: when the
codec is wired AND the storage adapter exposes saveBinaryBlob, it
encodes the connections, stores them at `_hnsw_conn/<nodeId>`, and
records `connections: {}` in saveHNSWData as the marker. Otherwise the
legacy JSON-array path is taken. TWO load sites use a matching
`restoreNodeConnections` helper that tries loadBinaryBlob first and
falls back to the legacy hnswData.connections field on miss / decode
error. Format convergence is lazy: pre-2.4.0 nodes still load via the
legacy path, then write the compressed form on next dirty save.
- brainy.ts wireConnectionsCodec — runs alongside wireMmapVectorBackend
during init. Activates when (a) the graph:compression provider is
registered and (b) the metadata index exposes its idMapper. Unlike the
mmap-vector backend, this layer engages on EVERY brainy 7.25.0
adapter — the blob primitive itself is universal; only the codec
presence gates activation.
- Provider interface GraphCompressionProvider in plugin.ts — encode +
decode static signatures. Brainy depends on the interface; cortex's
registered { encode: encodeConnections, decode: decodeConnections }
satisfies it structurally.
Tests (1437 total, +4 vs prior tip):
- tests/unit/hnsw/connections-codec.test.ts — 4 unit tests with a JSON
mock provider: single-level round-trip, empty-Map round-trip (one-byte
buffer), multi-level fan-out round-trip, and silent-drop of UUIDs the
decoding idMapper no longer knows. The real cross-language byte
format is exercised when cortex 2.4.0 wires its delta-varint
encode/decode in.
This completes the brainy half of the 2.4.0 storage foundation: stable
ids (#23), mmap vectors (#24), graph link compression (#25), and
column-store interchange (#26). Coordinated release as brainy 7.26.0 +
cortex 2.4.0 follows.
David Snelling
617c156feb