#Databases

Discuss core operating system concepts (memory management, processes vs threads) and relate them to database indexing and I/O performance.

Explain how database indexes work internally. Discuss B-Trees, B+ Trees, clustered vs non-clustered indexing, and index lookup performance.

Design a Promo Code System for Blinkit where promotions can depend on user segments, region, checkout amount, validity period, budget caps, and other parameters. The marketing team must also be able to configure and manage these promotions. Cover the following aspects: - Functional and non-functional requirements - Scale estimations - API design - High-level design (HLD) and scaling strategy - Consistency vs availability trade-offs - Region-specific request handling using Kafka partitions - Entity identification, schema design, and ER diagram

Explain what Redis is, its data structures, and common production use cases such as caching, rate limiting, and session storage.

Compare SQL and NoSQL databases. What are the key architectural trade-offs between ACID compliance, scalability, schema flexibility, and query complexity?