Data Partitioning and Sharding Questions

Techniques and operational practices for horizontally partitioning data across multiple database instances or storage nodes to achieve scale, improve performance, and manage growth. Includes selection and design of partition and shard keys to evenly distribute load and avoid hotspots, with range based, hash based, and directory based approaches and consistent hashing mechanisms. Covers handling uneven distribution and data skew, hotspot detection and mitigation, and the impact of partitioning on query patterns such as joins and cross shard queries. Explains implications for transactions and consistency, including transactional boundaries that span partitions and approaches to distributed transactions and compensation. Describes resharding and online data migration strategies, rolling rebalances, and methods to minimize downtime and data movement. Emphasizes operational concerns including shard management, automation, monitoring and alerting, failure recovery, and performance tuning. Discusses trade offs between simplicity, latency, throughput, and operational complexity and highlights considerations for both transactional and analytical workloads, including routing, caching, and coordination patterns.

HardTechnical

70 practiced

Develop a cost model to compare two choices for scaling a sharded datastore: adding more smaller instances versus upgrading to fewer larger instances. Include hardware, licensing, operational overhead, failover impact, and migration complexity in your model and describe how you'd apply it to a decision.

MediumSystem Design

81 practiced

Design an approach to support global secondary indexes (GSIs) in a sharded OLTP system where the primary shard key is user_id but queries require fast lookup by email (unique). Discuss options: global index service, index per shard with routing, or consistent centralized index, and state trade-offs.

MediumTechnical

102 practiced

How would you compute a global top-K (e.g., top 100 most purchased products) when underlying data is sharded across 200 nodes? Discuss algorithms and trade-offs between accuracy, latency, and resource usage.

MediumTechnical

84 practiced

Describe a backup and recovery strategy for a sharded cluster that guarantees point-in-time recovery for the entire logical dataset. Include coordination between shard backups and replaying logs across shards to restore a consistent global state.

MediumTechnical

87 practiced

Describe a programmatic approach to detect data skew across shards using production telemetry. Explain what signals you'd compute, how you'd normalize for traffic patterns, and one automated mitigation you could apply when a shard is overloaded.

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