Database Scalability and High Availability Questions

Architectural approaches and operational practices for scaling and maintaining database availability. Topics include vertical versus horizontal scaling trade offs; replication topologies, leader and follower roles, read replicas and replica lag; read write splitting and connection pooling; sharding and partitioning strategies including range based, hash based, and consistent hashing approaches; handling hot partitions and data skew; federation and multi database federation patterns; cache layers and cache invalidation; rebalancing and resharding strategies; distributed concurrency control and transactional guarantees across shards; multi region deployment strategies, cross region failover and disaster recovery; monitoring, capacity planning, automation for failover and backups, and cost optimization at scale. Candidates should be able to pick scaling approaches based on read and write patterns and explain operational complexity and trade offs introduced by distributed data.

HardTechnical

39 practiced

For a high-throughput event ingestion table, design a backpressure and throttling strategy to protect the database when consumers lag. Include how you'd surface backpressure to producers, incremental throttling policies, and considerations for SLA adherence.

EasyTechnical

36 practiced

Define replication lag and read replica in a distributed database. Describe two practical causes of replication lag and one operational approach to mitigate each cause.

HardTechnical

61 practiced

You need to guarantee serializable transactions across two shards without a central coordinator that becomes a bottleneck. Propose a lock-free or low-coordination protocol that provides strong consistency, explain how it handles conflicts and network partitions, and state its limitations.

MediumTechnical

47 practiced

Explain database federation and multi-database federation patterns. Provide an example architecture where federation is preferable to sharding and another where federation introduces unacceptable complexity.

MediumSystem Design

33 practiced

Your OLTP database supports a leaderboard feature that updates scores at high rate and serves read-heavy traffic. Reads require near-real-time accuracy. Suggest a combined architecture using sharding, caching, and/or in-memory stores to meet latency and consistency needs. Explain trade-offs and how to handle failure cases.

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