# 2026-02-06

## Morning
- Implemented two-tier caching system (`CacheMiddleware`)
  - Redis L1 with configurable TTL (default 5min)
  - In-process LRU L2 with 1000 entry cap and 30s TTL
  - Cache invalidation via Redis pub/sub — when any instance invalidates a key, all instances evict from L2
  - Unit tests: 23 new tests, all passing
  - PR #355 opened, assigned Alice for review

- Sprint planning meeting (10:00-11:00)
  - Next sprint focus: product search migration from Elasticsearch to Milvus
  - Bob prioritized: search relevance > search speed > faceted filtering
  - Estimated 2 weeks for full migration
  - Diana will update the frontend search UI to support semantic search suggestions

## Afternoon
- Started Milvus integration for product search
  - Created `ProductSearchService` class with hybrid search (vector + scalar filtering)
  - Schema: product_name (VARCHAR), description (VARCHAR), embedding (FLOAT_VECTOR, 1536d), category (VARCHAR), price (FLOAT), in_stock (BOOL)
  - Index type: IVF_FLAT with nlist=1024 for 500K+ products
  - Initial benchmark: 15ms p99 latency for top-10 search on 100K products

- Met with Diana about search UI
  - She'll add "Did you mean..." suggestions using our search API
  - Search results will show relevance score as a visual bar
  - Mobile search will get voice input support (Web Speech API)

## Evening
- Investigated the payment webhook timeout issue from yesterday
  - Root cause: Stripe retry logic conflicts with our idempotency check
  - When webhook times out, Stripe retries, but our handler rejects the duplicate
  - Solution: implement Kafka-based async webhook processor
    1. Webhook endpoint immediately ACKs (200) and publishes to `payment.webhooks` topic
    2. Consumer processes events idempotently using Stripe event ID as key
    3. Dead letter queue for events that fail 3 times
  - PR #358 with initial implementation, needs integration test
