AWS DynamoDB Interview Questions and Answers
Experienced / Expert level questions & answers
Ques 1. Explain the concept of Global Secondary Index (GSI) in DynamoDB.
A Global Secondary Index allows querying a table based on alternate keys in addition to the primary key. It provides more flexibility in querying data.
Ques 2. What is the difference between On-Demand and Provisioned Throughput in DynamoDB?
On-Demand Throughput allows you to pay per request without capacity planning, while Provisioned Throughput requires capacity planning and offers cost savings for consistent workloads.
Ques 3. Explain the best practices for designing tables in DynamoDB.
Best practices include choosing the right primary key, using appropriate read and write capacities, avoiding hot keys, and utilizing secondary indexes judiciously.
Ques 4. What is the purpose of the DynamoDB Accelerator (DAX)?
DAX is an in-memory caching service that provides fast read access to frequently accessed data in DynamoDB, reducing the need to read from the DynamoDB table directly.
Ques 5. Explain the concept of Provisioned Concurrency in DynamoDB.
Provisioned Concurrency is a feature that ensures that a specified number of read and write capacity units are always available for your table, reducing warm-up times.
Ques 6. Explain the concept of Auto Scaling in DynamoDB.
Auto Scaling automatically adjusts the provisioned read and write capacity based on the actual usage of a table. It helps in handling varying workloads.
Ques 7. What are the limitations of DynamoDB?
Limitations include a maximum item size of 400 KB, a maximum of 256 tables per region per account, and a maximum provisioned capacity of 40,000 read and write capacity units.
Ques 8. Explain the differences between DynamoDB and Amazon RDS.
DynamoDB is a NoSQL database service, while Amazon RDS is a relational database service. DynamoDB is designed for scalability and high availability, while RDS offers traditional relational database features.
Ques 9. What is the purpose of the 'TransactWriteItems' operation in DynamoDB?
'TransactWriteItems' allows you to perform multiple write operations as a single, atomic transaction. Either all the operations in the transaction succeed, or none of them are applied.
Ques 10. Explain the benefits of using DynamoDB Accelerator (DAX).
DAX provides low-latency read access to DynamoDB tables by caching frequently accessed data. It reduces the need to read from the DynamoDB table directly, improving application performance.
Ques 11. How does DynamoDB handle transactions?
DynamoDB supports transactions using the 'TransactWriteItems' operation. It allows you to group multiple write operations into a single, atomic transaction.
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