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Fast Development Mode

Overview​

The dev-fast script provides an optimized local development experience with 4-6x faster WebSocket streaming performance compared to the standard dev script.

Usage​

# Using pnpm (recommended)
pnpm dev-fast

# Using the script directly
./dev-fast

# With AWS profile
pnpm dev-fast --profile your-profile

What It Does​

  1. Compiled Subscriber-Fanout: Builds and runs the compiled JavaScript version instead of tsx watch, eliminating TypeScript compilation overhead
  2. Increased MongoDB Pool: Sets MONGODB_MAX_POOL_SIZE=10 (vs default 2) for better concurrent connection handling
  3. Faster WebSocket Updates: Reduces throttling from 100ms to 25ms in development (4x more updates per second)
  4. Memory Optimization: Sets NODE_OPTIONS="--max-old-space-size=4096" to prevent garbage collection pauses
  5. Development Environment: Properly sets NODE_ENV=development for all services

Performance Improvements​

  • WebSocket streaming: 4-6x faster perceived response time
  • Database operations: ~2x faster with larger connection pool
  • Overall responsiveness: Significantly improved, closer to production performance

When to Use​

Use dev-fast when:

  • Testing AI streaming responses
  • Working with real-time features
  • Demonstrating the app locally
  • Performance testing

Use regular dev when:

  • You need hot-reload for subscriber-fanout code
  • You're debugging TypeScript compilation issues
  • Initial setup or configuration changes

Trade-offs​

  • Build time: Adds ~5-10 seconds startup time to build subscriber-fanout
  • Hot reload: Subscriber-fanout changes require restart (client still hot-reloads)
  • Memory usage: Uses more memory due to larger pools and compiled code

Troubleshooting​

If you encounter issues:

  1. Ensure all dependencies are installed: pnpm install
  2. Clean build artifacts: pnpm clean
  3. Check MongoDB is running and accessible
  4. Verify AWS credentials are configured

Technical Details​

The optimizations include:

  • MongoDB maxPoolSize: 10 (configurable via MONGODB_MAX_POOL_SIZE)
  • WebSocket throttle: 25ms in development vs 100ms in production
  • Node.js heap size: 4GB
  • Compiled TypeScript for critical path services