Distributed Database Layer

A distributed database system built with TypeScript and PostgreSQL, featuring consistent hashing, vector clocks for versioning, and quorum-based replication.

Architecture

┌─────────────────────────────────────────────────────────┐
│                     Express API                         │
├─────────────────────────────────────────────────────────┤
│  Hash Ring          │  Vector Clock    │  Handler       │
│  (CRC32)            │  (Versioning)    │  (CRUD + Quorum)│
├─────────────────────────────────────────────────────────┤
│     PostgreSQL 1    │  PostgreSQL 2    │  PostgreSQL 3  │
└─────────────────────────────────────────────────────────┘

Features

• Consistent Hashing - CRC32-based hash ring for deterministic data distribution
• Vector Clocks - Conflict detection and causal ordering of events
• Quorum Replication - Write succeeds only when majority of replicas confirm
• Automatic Failover - Reads try multiple replicas on failure

Quick Start

# Start PostgreSQL instances
docker compose up -d

# Install dependencies
npm install

# Run the server
npm run dev

API Endpoints

Method	Endpoint	Description
POST	/db	Create record
GET	/db/:id	Get record by ID
PUT	/db/:id	Update record

Example

# Create
curl -X POST http://localhost:8080/db \
  -H "Content-Type: application/json" \
  -d '{"name": "John", "email": "john@example.com"}'

# Read
curl http://localhost:8080/db/{id}

# Update
curl -X PUT http://localhost:8080/db/{id} \
  -H "Content-Type: application/json" \
  -d '{"name": "John Updated"}'

Configuration

[server]
port = 8080

[postgres]
nodes = ["postgres://...@localhost:5432/db1", "..."]

[replication]
factor = 2              # Number of replicas per record
hash_ring_replicas = 50 # Virtual nodes per physical node

Tech Stack

• Runtime: Node.js + TypeScript
• Framework: Express.js
• Database: PostgreSQL
• Hashing: CRC-32