HeliosDB Lite v3.6.0 Release Notes

Correction: what 3.6.0 serves

HeliosDB Lite 3.6.0 serves the PostgreSQL wire protocol and a REST API; an MCP server, an Oracle listener and a gRPC query API are planned. The graph, BM25 and hybrid-search SQL functions, PREPARE COMPILED and the MCP server extensions described below are not reachable from SQL, REST or MCP in 3.6.0; they are planned. Code-Graph and Graph-RAG are available in HeliosDB Nano today and are planned for HeliosDB Lite.

Theme: Edge-native RAG — graph + BM25 + hybrid search with Bloom-filter acceleration

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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.

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What’s New

Graph Engine

Graph storage with adjacency lists. v3.6.0 ships with an in-memory implementation.

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

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

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

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

Planned: a native MCP server for HeliosDB Lite is on the roadmap and is not part of 3.6.0. The tools and resources below describe the planned extension set:

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

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Known Limitations

• Graph storage is in-memory in v3.6.0.
• graph_* SQL functions operate on the in-memory store until persistent backends ship.

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Migration

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

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Compatibility Matrix

Component	Version
PostgreSQL wire	14, 15, 16
Oracle wire	not in 3.6.0 (listener in preparation for an upcoming release)
MCP protocol	planned (no MCP server in 3.6.0)
HeliosProxy	0.3.0+