---
title: "HeliosDB Full v8.0: A 14-Protocol Native LSM, RocksDB-Free"
description: "v7.9.0→v8.0.0 retired RocksDB. Native LSM, custom WAL, content-addressed CAS, branch-aware GC. Speaks 14 wire protocols simultaneously without any third-party storage engine on the read or write path."
date: 2026-05-19
updated: 2026-05-19
tag: "Architecture"
canonical: https://www.heliosdb.com/blog/full-8-0-native-lsm-14-protocols.html
---

# HeliosDB Full v8.0: A 14-Protocol Native LSM, RocksDB-Free

v8.0.0 is a milestone release: HeliosDB Full no longer depends on RocksDB. The native LSM tree, custom WAL, content-addressed CAS, and branch-aware GC carry the read and write path end-to-end — while the engine continues to speak 14 wire protocols simultaneously. This post covers what changed, why we did it, and what it means for operators.

## Why retire RocksDB

RocksDB is excellent. We used it for years. Three things made the dependency increasingly awkward:

- **Branch semantics.** Git-like branches with copy-on-write at the storage layer want delta SSTables and branch-aware compaction. We were layering branch metadata on top of RocksDB's column families, which works, but the planner and the GC had to round-trip through a foreign abstraction every operation.
- **Time-travel reads.** MVCC versions on RocksDB go through `seqnum`-based snapshots. That's fine for short-lived snapshots; it's awkward for "give me this row as of timestamp T" with T anywhere in the retention window.
- **Compile times and binary size.** RocksDB pulled in C++ build tooling. Removing it dropped clean-build time materially and shaved ~12 MB off the release binary.

## The native LSM

v7.9.0 ported `heliosdb-vector` off RocksDB first — the easiest module to migrate, and the one with the loudest performance claim. v8.0.0 finished the job: every storage-touching crate is now on the native LSM. Highlights:

- **Direct-I/O WAL with single-write durability.** Aligned writes via `O_DIRECT`; the redundant secondary fsync the prior architecture used was retired in v7.7.3.
- **Content-addressed value storage.** Large values are deduplicated across rows and branches by content hash. Useful for embedding-heavy workloads where the same vector recurs across many tenants.
- **Branch-aware GC.** Tombstones and stale versions are reclaimed only when no live branch references them; the GC scheduler consults a branch/MVCC matrix before compacting.
- **Speculative filters.** When a query repeatedly probes a column with a similar value distribution, the engine maintains a probabilistic filter for the next probe.

Three of these four (content-addressed storage, branch-aware GC, speculative filtering) are documented as defensive publications in the HeliosDB IP register. They are public prior art; we describe them here in the same shape.

## 14 protocols, one storage engine

The wire-protocol adapters — PostgreSQL, MySQL, MongoDB, Redis, Cassandra, Oracle, MSSQL, DB2, Snowflake, Databricks, Pinecone, ClickHouse, HTTP, S3 — all sit above the same query planner sitting above the same storage engine. v8.0 doesn't change that surface; it changes what's underneath.

## Performance side-effects

The migration was conservative on perf claims. The numbers we're confident about:

- Branch creation: < 1 ms (was ~10 ms).
- Storage overhead at branch creation: 0 bytes of data, 256 bytes of metadata.
- Read performance on a branch: 97% of main branch.
- Time-travel point queries: same order of magnitude as live reads (was ~3× slower on RocksDB snapshots).
- Cold-build time: ~40% faster (no C++ toolchain).

## Operator impact

Storage is on-disk-compatible across the v7.9 → v8.0 cut: the LSM was already shipping in v7.9 with RocksDB sidelined, so the upgrade is zero-touch. The `rocksdb` Cargo dep is no longer in the dependency tree at all.

## What's next

v8.1 (already shipped) hardened the v8.0 implementations for end-user use. v8.2 added the agentic-ops skills repository for Claude Code & Codex. v8.3+ will continue the perf wave: HNSW-on-disk for billion-scale vector search, parallel compaction, async checkpointing.

HeliosDB Full is source-available under SSPL-1.0. Repository: [github.com/dimensigon/HDB-HeliosDB-Full](https://github.com/dimensigon/HDB-HeliosDB-Full).