Concepts

Availability, reliability, scalability, CAP theorem, consistency models, fault tolerance, PACELC, concurrency, and NFRs.

Write strategies, eviction policies, cache invalidation, distributed caching, Redis internals, and common cache failure patterns.

ACID, transaction isolation, indexing, CDC, pagination, connection pooling, and read-write splitting.

Key-value, document, column-family, search engines, graph databases, blob storage, NewSQL, OLTP vs OLAP, and choosing the right DB.

Message queue fundamentals, SQS internals, and RabbitMQ — delivery guarantees, routing, and failure handling.

Kafka architecture, producers, consumers, advanced internals, backpressure, and Kafka vs SQS vs RabbitMQ comparison.

Event sourcing, CQRS, outbox pattern, CDC, and combining inbox + outbox for reliable event delivery.

Stream processing, batch processing, Lambda and Kappa architectures, and schema evolution in data pipelines.

Network uncertainty, consensus, clocks, CRDTs, failure detection, Merkle trees, replication, sharding, and coordination services.