date: 2025-08-11 topics: [backend, architecture, bullmq, redis, mongodb, feed] day: 25

Day 25 – Materialized Feed Architecture with BullMQ & Redis

✅ What I Worked On

Designed scalable feed system using a denormalized Feed collection
Added PlantUML diagram for architecture visualization
Documented system structure in README.md
Wrote STAR-format examples for feed update events (like-added, answer-added, etc.)
Planned use of BullMQ workers for async feed updates
Decided on Redis queue + Mongo atomic $inc for counters

📚 What I Learned

How to separate read and write models for high-performance APIs
Event-driven updates using job queues
Benefits of materialized views for high-traffic feeds (inspiration from Twitter, Reddit, Stack Overflow)
Using PlantUML to visualize backend architecture

❌ Blockers

Confusion over how to keep isLike user-specific flag — debating whether to resolve at read time or precompute per user
Unsure about best retry/backoff settings in BullMQ for handling temporary Redis or Mongo outages
Need to figure out idempotency to avoid double increments when events are retried
Designing schema updates for Feed collection without breaking existing API consumers
Wondering how to handle backfill efficiently without locking collections or impacting live traffic

🧠 Reflection

Moving to an event-driven, materialized feed feels like a huge performance win for large-scale systems. Excited to start wiring the actual worker logic and test end-to-end job processing.