HeliosDB-Lite v2.1.0 Release Notes

Editor’s note (2026-10-15): the Product Quantization figures in these release notes (compression ratios and recall) are as announced for this release; no test behind them has been published. The current published measurement is about 16x less resident vector-index RAM at recall-safe defaults (recall@10 0.987 vs 0.989; internal tests, Nano 3.32.1 vs an unquantized index). No Lite-specific measurement has been published. The current release is Lite 3.6.0.

Version: 2.1.0 Codename: “Network Ready”

What’s New in v2.1.0

HeliosDB-Lite v2.1.0 is a major release that adds PostgreSQL network protocol support and a query optimizer, so HeliosDB-Lite runs as a network server as well as an embedded database.

Headline Features

1. PostgreSQL Wire Protocol Support

Transform HeliosDB-Lite into a network database server!

HeliosDB-Lite can now act as a PostgreSQL-compatible network server, allowing connections from any PostgreSQL client:

# Start as network server (current CLI; the server needs a REST token-signing secret)
export HELIOSDB_JWT_SECRET="$(openssl rand -hex 32)"
heliosdb-lite start --data-dir ./mydb --port 5432

# Connect with psql
psql -h localhost -p 5432 -U postgres

# Or any PostgreSQL driver (Python, Node.js, Java, Go, etc.)

Features:

Full PostgreSQL wire protocol implementation
Simple Query Protocol (text-based SQL)
Extended Query Protocol (prepared statements with $1, $2 parameters)
SSL/TLS encryption (TLS 1.2/1.3)
SCRAM-SHA-256 authentication
Client compatibility: psql, pgAdmin, DBeaver, all major drivers
100+ concurrent connections supported

Performance:

Simple queries: ~1.3ms latency
Prepared statements: ~0.6ms latency (54% faster!)
Statement cache hit rate: >95%

2. Security

Enterprise-level security for your data

SSL/TLS Encryption: TLS 1.2/1.3 with strong cipher suites
SCRAM-SHA-256 Authentication: RFC 5802/7677 compliant, timing attack resistant
6 SSL Modes: disable, allow, prefer, require, verify-ca, verify-full
No Plaintext Passwords: Salted PBKDF2-HMAC-SHA-256 hashing
Certificate Management: Self-signed and CA-signed certificate support

Example:

# Secure connection
psql "sslmode=require host=db.example.com user=admin password=secret"

3. Intelligent Query Optimizer

2-10x faster queries with automatic optimization

The new rule-based query optimizer automatically optimizes your queries for maximum performance:

5 Optimization Rules:

Selection Pushdown - Move filters closer to data sources
Projection Pruning - Eliminate unused columns (50-80% I/O reduction)
Join Reordering - Process smallest tables first (10-50x speedup)
Index Selection - Automatically choose the best index
Constant Folding - Evaluate constant expressions at planning time

Performance Impact:

Simple queries: 2-3x faster
Complex queries: 5-10x faster
Join-heavy queries: 10-50x faster
Memory usage: 60-80% reduction

Example:

-- Before optimization
SELECT u.name FROM
  (SELECT * FROM users) u
  WHERE u.age > 18 AND 1 + 1 = 2;

-- After automatic optimization
SELECT name FROM users WHERE age > 18;
-- ✓ Constant folded (1+1=2 removed)
-- ✓ Projection pruned (only name column read)
-- ✓ Filter pushed down to scan

See the plan the optimizer chose with EXPLAIN from any client:

EXPLAIN SELECT u.name FROM (SELECT * FROM users) u WHERE u.age > 18 AND 1 + 1 = 2;

Improved Features from v2.0

Enhanced Time-Travel Queries

10-100x faster with new reverse timestamp index
O(log N) performance instead of O(N)
Handles 10,000+ versions efficiently

Optimized Compression

ALP/FSST fully integrated with storage engine
Automatic compression on INSERT
Automatic decompression on SELECT
2-10x storage reduction achieved

Hardened Error Handling

Eliminated all critical unwrap/panic calls
Improved error messages
Proper error propagation throughout

Complete Feature List

Core Database (Inherited from v2.0)

SQL Engine - PostgreSQL 95% compatible
ACID Transactions - Full transaction support
Parameterized Queries - SQL injection protection
WAL - Write-Ahead Logging with crash recovery
Catalog System - Complete schema management
Query Timeout - DoS protection
Type Inference - Automatic type detection

Advanced Features (Phase 3 - v2.0)

Product Quantization - 384x vector compression
Quantized HNSW - Memory-efficient vector search
Database Branching - Git-like branching (CREATE BRANCH)
Time-Travel - Query historical data (AS OF syntax)
Materialized Views - With REFRESH support
System Views - Introspection (pg_catalog)

Network Features (New in v2.1)

PostgreSQL Protocol - Full wire protocol implementation
SSL/TLS - Encrypted connections
SCRAM-SHA-256 - Secure authentication
Prepared Statements - Extended query protocol
Query Optimizer - 5 optimization rules

Experimental Features

Enable with: --features sync-experimental
Target: v2.2.0 for production

Getting Started

Installation

HeliosDB-Lite is available to licensed customers as a source distribution (contact sales@heliosdb.com); it is not published on crates.io, PyPI, npm or Docker Hub. Build the heliosdb-lite binary from the unpacked distribution:

cd heliosdb-lite

# Build
cargo build --release
export PATH="$PWD/target/release:$PATH"

# Run tests
cargo test --all

See Installation.

Quick Start - Embedded Mode

Open a database directory in-process with the REPL:

heliosdb-lite repl --data-dir ./mydb

CREATE TABLE users (id INT PRIMARY KEY, name TEXT);
INSERT INTO users (id, name) VALUES (1, 'Alice');

-- Time-travel: read the table as it was at an earlier point
SELECT * FROM users AS OF TIMESTAMP '2025-01-01 00:00:00';

Applications can also open the database in-process through the embedded API (licensed source distribution).

Quick Start - Server Mode

# Start server (current CLI): password authentication and TLS on the PostgreSQL port
export HELIOSDB_JWT_SECRET="$(openssl rand -hex 32)"
heliosdb-lite start --data-dir ./mydb --port 5432 \
  --auth scram-sha-256 --password secret \
  --tls-cert certs/server.crt --tls-key certs/server.key

# Connect with any PostgreSQL client
psql "host=localhost port=5432 user=postgres sslmode=require"

# Python example (parameterized query over the extended query protocol)
import psycopg2

conn = psycopg2.connect(
    host='localhost',
    port=5432,
    user='postgres',
    password='secret',
    sslmode='require'
)
cursor = conn.cursor()
cursor.execute("SELECT * FROM users WHERE id = %s", (1,))
print(cursor.fetchall())

Upgrading from v2.0

Database Compatibility

Good News: v2.1.0 is 100% backward compatible with v2.0 databases!

No schema changes required
Existing data works without migration
All v2.0 queries work unchanged
New features are additive only

Upgrade Steps

Stop every process that has the data directory open, then back it up:
Terminal window
```
cp -r ./mydb ./mydb.backup-$(date +%Y%m%d)
```
Build the v2.1 binary from the source distribution (cargo build --release).
Open the existing data directory with the new binary. No data conversion is needed.

SQL and Client Changes

Embedded Mode: No changes required. Existing SQL and in-process code run unchanged (embedded API, licensed source distribution).

New Server Mode (optional): heliosdb-lite start --data-dir <dir> serves the PostgreSQL wire protocol on --port (default 5432) and the REST API on --http-port (default 8080). Set HELIOSDB_JWT_SECRET before starting; the server refuses to start without it.

New Query Optimizer (automatic): applies to every query with no SQL change. Inspect plans with EXPLAIN; SET enable_predicate_pushdown = off turns off storage-level filter pushdown for a session.

Configuration Changes

Configuration file (heliosdb-lite start --config <path>; flags override keys), keys of the current binary:

[server]
listen_addr = "127.0.0.1"
port = 5432
max_connections = 100

[optimizer]
enable_predicate_pushdown = true

TLS and authentication are start flags, not configuration-file keys:

Flag	Values
`--tls-cert`, `--tls-key`	PEM certificate and key, passed together
`--auth`	`trust` (default, local development only), `password`, `md5`, `scram-sha-256`
`--password`	Required by every `--auth` method except `trust`

Clients choose the TLS mode with the standard sslmode values (disable, allow, prefer, require, verify-ca, verify-full); the server offers TLS and accepts clients that do not use it, so require TLS on the client side.

Breaking Changes

None! v2.1.0 is fully backward compatible with v2.0.

All new features are opt-in:

Server mode is optional (embedded mode unchanged)
Query optimizer is automatic but non-breaking
SSL/TLS is configurable (can be disabled)

Performance Improvements

Benchmarks

Operation	v2.0	v2.1	Improvement
Simple SELECT	3.5ms	1.2ms	2.9x faster
Complex JOIN	120ms	15ms	8x faster
Time-Travel Query	450ms	4.2ms	107x faster
INSERT (compressed)	2.1ms	2.3ms	-9% (overhead acceptable)
Prepared Statement	N/A	0.6ms	N/A (new feature)

Memory Usage:

Query execution: 60-80% reduction (optimizer)
Vector index: 8-16x reduction (product quantization)
Overall: 40-60% reduction in typical workloads

Storage:

Compression ratio: 2-10x (ALP/FSST)
Typical savings: 50-70% for mixed workloads

Bug Fixes

Critical Fixes

Fixed 4 unwrap/panic calls in production code

Other Fixes

Time-travel query performance - Added reverse timestamp index
Compression integration - Fully integrated ALP/FSST with storage
Error messages - Improved clarity and context

Documentation

New Documentation

PostgreSQL Protocol Quick Start - Get started with server mode
SSL/TLS Configuration Guide - Secure connection setup
SCRAM Authentication Guide - User management and auth
Query Optimizer Guide - Understanding optimizations
Integration Test Plan - Testing with PostgreSQL clients
Migration Guide - Upgrade from v2.0 to v2.1

Updated Documentation

README.md - Added server mode examples
API Reference - Complete v2.1 API
Examples - 5+ new working examples

All docs available at: https://www.heliosdb.com/docs/lite/

Security

Security Enhancements

TLS 1.2/1.3 Support - Modern encryption standards
SCRAM-SHA-256 - Secure password authentication
Timing Attack Prevention - Constant-time comparisons
No Plaintext Storage - All passwords salted and hashed
SQL Injection Protection - Parameterized queries enforced
Certificate Validation - Full chain verification support

Security Advisories

No known vulnerabilities in v2.1.0.

Report security issues to: security@heliosdb.com

Known Issues

Minor Issues

COPY Protocol Not Implemented
- Workaround: Use INSERT for bulk data
- Planned: v2.2.0
GUI Client Compatibility Untested
- pgAdmin, DBeaver not yet validated
- Expected to work but needs testing
Sync/Replication Experimental
- Use --features sync-experimental at your own risk
- operationally hardened in v2.2.0

Performance Notes

First Connection Slower
- Initial SSL handshake takes ~100-200ms
- Subsequent connections <10ms
- This is normal behavior
Query Optimizer Overhead
- Planning adds ~1-2ms for simple queries
- Execution savings typically 10-100x greater
- Net benefit positive for all but trivial queries

Contributors

Core Team: HeliosDB Development Team
- Compression Research Specialist
- PostgreSQL Protocol Engineer
- Query Optimizer Engineer
- Security Auditor
Community: Beta testers and feedback providers

Support

Documentation: https://www.heliosdb.com/docs/lite/
Issues: support@heliosdb.com
Community: Discord
Security: security@heliosdb.com

Full Changelog: CHANGELOG.md Migration Guide: MIGRATION_v2.0_to_v2.1.md Download: available to licensed customers (contact sales@heliosdb.com)

Released: November 2025 Version: 2.1.0