HeliosDB Lite v3.6.0 Release Notes

Release Date: 2026-04-16 Theme: Edge-native RAG — graph + BM25 + hybrid search with Bloom-filter acceleration

Highlights

Lite v3.6.0 brings the same RAG primitives as Nano v3.11.0, with a Lite-specific advantage: BM25 lookups are accelerated by Lite’s existing probabilistic-filter infrastructure (Bloom, Cuckoo, XOR, Ribbon filters), making text search faster on large corpora at the edge.

What’s New

Graph Engine (NEW)

Backend-agnostic graph storage with adjacency lists. The EdgeStore trait abstracts over storage backends — v3.6.0 ships with an in-memory implementation; RocksDB and NativeBackend variants are coming in v3.7.

SELECT * FROM graph_traverse(
  start_node => 'uuid-here',
  edge_label => 'KNOWS',
  depth => 2
);

SELECT * FROM graph_shortest_path(
  from_node => 'uuid-a',
  to_node   => 'uuid-b',
  algorithm => 'astar',
  weight_col => 'distance'
);

Algorithms: BFS, Dijkstra, A*.

Full-Text BM25 with Bloom-Filter Acceleration (NEW)

Lite’s BM25 implementation uses existing Bloom/Cuckoo filters to skip non-existent terms during lookup — significantly faster on large indexes:

-- BM25 with default Bloom acceleration
SELECT * FROM documents
WHERE bm25_match(content, 'rust database edge')
ORDER BY bm25_score(content, 'rust database edge') DESC
LIMIT 10;

-- Choose specific filter type
SELECT * FROM bm25_with_filter(
  column => content,
  query  => 'rust database edge',
  filter_kind => 'cuckoo'
);

Hybrid Search + RRF/MMR (NEW)

SELECT * FROM hybrid_search(
  table_name   => 'documents',
  query_text   => 'rust database edge',
  query_vector => embed('rust database edge'),
  vector_column=> 'embedding',
  text_column  => 'content',
  fusion       => 'mmr',     -- 'rrf', 'mmr', or 'linear'
  lambda       => 0.7,        -- MMR diversity tradeoff
  limit        => 20
);

Compiled Query Plans (NEW)

PREPARE COMPILED find_similar AS
  SELECT * FROM hybrid_search(...);

EXECUTE find_similar(embed('my query'));

LRU-cached plans skip parsing/planning on repeat execution.

MCP Server Extensions (NEW)

4 new tools and 2 new resources accessible via the existing MCP server:

Tools: heliosdb_hybrid_search, heliosdb_graph_traverse, heliosdb_graph_path, heliosdb_embed_and_store Resources: heliosdb://schema/{table}, heliosdb://stats/{table}

Performance: Arena Allocation (Internal)

RequestArena (bumpalo-based) reduces allocator pressure in hot paths. Available to extension developers via heliosdb_lite::runtime::RequestArena.

Known Limitations

Graph storage is in-memory in v3.6.0. Backend-agnostic trait is in place; RocksDB and NativeBackend implementations land in v3.7.
graph_* SQL functions operate on the in-memory store until persistent backends ship.
MCP extensions live in a separate mcp_extensions module while the legacy mcp module is migrated.

Migration

No breaking changes. v3.6.0 is fully wire-compatible with v3.5.x.

Compatibility Matrix

Component	Version
PostgreSQL wire	14, 15, 16
Oracle wire	(subset)
MCP protocol	1.0
HeliosProxy	0.3.0+