Design a scalable search service with sharding

## Technical Design: Search + Sharding Trade-offs Design a search service that lets users query documents/products with keywords. ### Functional requirements - `GET /search?q=...` returns top results ranked by relevance. - Support basic filtering (e.g., category, language, tenant/app id). - P95 latency target (e.g., < 200 ms) and ability to scale to large corpora. ### Non-functional requirements - Data size grows to billions of docs. - Frequent reads, continuous ingestion/updates. - High availability. ### Prompt 1. Describe how you would implement the core search algorithm at a high level (indexing + querying). 2. Propose a **sharding strategy** for the index. 3. Discuss trade-offs: latency, cost, rebalancing, hot keys, consistency, and operational complexity. No need to write production code, but be concrete about components and data flows.