---
title: "HeliosDB Lite v3.6.0 Release Notes"
---

# HeliosDB Lite v3.6.0 Release Notes

:::caution[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

---

## 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

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

```sql
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:

```sql
-- 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

```sql
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

```sql
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}`

---

## Known Limitations

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

---

## 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 | 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+ |