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Tellstone

Introduction

Tellstone is an ultra-high-performance, cloud-native in-memory key/value store written entirely in Go. It speaks two protocols over TCP — a compact custom binary protocol and a Redis-compatible (RESP2) protocol — on top of a sharded, low-contention storage engine with optional TTL eviction, at-rest encryption, and per-shard WAL persistence for crash recovery.

+---------------------------------------------+
|             Your K8s Cluster                 |
|                                               |
|  [App Pod] --( binary :9988 / RESP :6379 )-->|
|                                               |
|     +---------------------------------+       |
|     |        TELLSTONE CORE           |       |
|     |  (N Sharded In-Memory Buckets — GOMAXPROCS by default)|       |
|     +---------------------------------+       |
+---------------------------------------------+

Why Tellstone?

Section titled “Why Tellstone?”

Many managed databases (PostgreSQL, MySQL, …) become bottlenecks under high-frequency workloads. Tellstone offers a lean, memory-efficient buffer in front of them:

  • Zero-copy binary protocol — direct binary messages avoid text parsing or Protobuf overhead for maximum performance.
  • Redis-compatible — an optional RESP2 listener lets you drive Tellstone with redis-cli, redis-benchmark, memtier_benchmark, and existing Redis client libraries for seamless integration.
  • Sharded, low-contention engine — N shards (default GOMAXPROCS, configurable) indexed by key hash, each guarded by its own RWMutex, for near-linear scaling across cores.
  • Configurable TTL eviction — an active timing wheel evicts expired keys in O(1); lazy eviction on read backs it up for efficient key management.
  • Optional at-rest encryption — ChaCha20-Poly1305, off by default, for secure data storage when needed.
  • Per-shard WAL persistence — an append-only write-ahead log per shard for crash recovery. Disabled by default; enable with --enable-persistence.
  • Metrics & tracing — a built-in Prometheus exporter and optional OpenTelemetry tracing for comprehensive observability.

What’s here today vs. on the roadmap

Section titled “What’s here today vs. on the roadmap”

Tellstone’s core engine (Phase 1) and persistence (Phase 1.5) are done: the sharded store, both protocols, TTL eviction, encryption, observability, and per-shard WAL for crash recovery. Clustering, replication, and a broader command set are Phase 2 — see the clustering page for current status.

Phase 1 — Core Engine (done): sharded in-memory engine with TTL eviction, binary TCP protocol, Redis-compatible RESP listener (PING/GET/SET/DEL), at-rest encryption, Prometheus metrics, and OpenTelemetry tracing.

Phase 1.5 — Persistence (done): per-shard append-only WAL with TTL-aware replay, tombstone deletes, crash-safe truncation, and zero-allocation writes. Enable with --enable-persistence.

Phase 2 — Distributed (future): event-driven replication (e.g. NATS JetStream), write-through/write-behind persistence to external stores, official client SDKs, and a broader RESP command set (RESP3, INCR, EXPIRE, MULTI/EXEC).

Where to go next

Section titled “Where to go next”