Amazon Database Interview Questions and Answers
Q: What is AWS RDS?
Answer: Amazon RDS is a managed relational database service that provides organizations with a fully managed database in the cloud. Amazon Aurora, MariaDB, Microsoft SQL Server, MySQL, Oracle, and PostgreSQL are just six of the database engines it supports. A relational database refers to a specific type of database that organizes data into tables consisting of rows and columns. Amazon RDS offers a reliable and affordable relational database solution, designed to meet industry standards. With the ability to adjust its capacity according to your needs, it ensures cost-efficiency.
Q: Name the database types in RDS?
Answer: Following are the types of databases in RDS – MYSQL, PostgreSQL, SQL server, Aurora, Oracle, and MariaDB etc.
Q: What is DynamoDB?
Answer: DynamoDB is a NoSQL database offered by Amazon Web Services (AWS). For companies that need effective data management solutions, it is made to offer great performance, and scalability. Unlike conventional relational databases, DynamoDB uses a non-relational data paradigm, enabling more adaptable and scalable data storage.
Q: What is the difference between SQL and NoSQL Database in AWS?
Answer: The primary difference between SQL and NoSQL databases lies in their data models and the way they handle data.
| Features | SQL Database | NoSQL Database |
| Data Model | SQL databases, uses a structured data model. They store data in tables with predefined schemas, consisting of rows and columns. | NoSQL databases use a flexible and schema-less data model. They can store unstructured, semi-structured, or structured data, such as key-value pairs, documents, graphs, or time-series. |
| Schema | SQL databases enforce a rigid schema, meaning the structure of the data is predefined and must adhere to a specific schema. Changes to the schema often require altering the database structure. | NoSQL databases allow for dynamic schema changes, meaning the structure of the data can evolve over time without requiring a predefined schema. Each record in a collection can have different attributes. |
| Query Language | SQL databases utilize Structured Query Language (SQL) to manage and manipulate data. SQL provides a standardized syntax for querying, inserting, updating, and deleting data. | NoSQL databases use various query languages specific to their data models, such as MongoDB’s query language for document databases. |
| Data Integrity | SQL databases offer strong data integrity and support ACID (Atomicity, Consistency, Isolation, Durability) properties. Transactions ensure data consistency and reliability. | NoSQL databases often sacrifice some aspects of data integrity (like strong consistency) for increased scalability and performance. They may provide eventual consistency or other consistency models. |
| Scalability | SQL databases generally scale vertically by increasing the resources (CPU, RAM) of the database server. Scaling horizontally across multiple servers can be more complex. | NoSQL databases are designed for horizontal scalability. They can distribute data across multiple servers, allowing for seamless scalability by adding more servers to handle increased workload. |
Q: What are the managed database services provided by AWS?
Answer: AWS provides a range of managed database services that handle administrative tasks, such as backups, software patching, scaling, and infrastructure management. The key managed database services offered by AWS are: – Amazon RDS, Amazon Aurora, Amazon DynamoDB, Amazon DocumentDB, Amazon Neptune, Amazon ElastiCache, and Amazon Redshift.
Q: What is Redshift Spectrum?
Answer: Amazon Redshift Spectrum is a feature of Amazon Redshift, the fully managed data warehousing service offered by AWS. Redshift Spectrum enables you to query data directly from Amazon S3, the cloud storage service, without the need to load or move the data into Redshift tables. It combines the power and scalability of Redshift with the flexibility and cost-effectiveness of storing data in S3.
Q: What is the Amazon ElastiCache?
Answer: Amazon ElastiCache is a fully managed, in-memory caching service provided by AWS. It is designed to enhance the performance and scalability of applications by seamlessly integrating with popular open-source in-memory engines like Redis and Memcached. ElastiCache simplifies the deployment, operation, and scaling of a caching layer, allowing applications to retrieve frequently accessed data quickly and reduce the load on backend databases or other data stores.
Q: When will you prefer to use Provisioned IOPS over normal RDS storage?
Answer: Provisioned IOPS (Input/Output Operations Per Second) is a feature available for Amazon RDS (Relational Database Service) that allows you to allocate a specific amount of IOPS to your database storage.
Provisioned IOPS is the preferred choice over normal RDS storage for batch-oriented workloads. When dealing with batch processing tasks, which involve large data sets and complex operations, Provisioned IOPS offers predictable and consistent I/O performance.
Q: How do Amazon RDS, DynamoDB, and Redshift Differ from Each Other?
Answer: Amazon RDS is ideal for traditional SQL-based relational databases, DynamoDB excels in handling flexible and scalable NoSQL workloads, while Redshift is specifically tailored for data warehousing and analytical use cases. The choice between these services depends on factors like data model requirements, scalability needs, performance expectations, and the nature of your application or workload.
Q: What is the purpose of standby RDS instance?
Answer: The purpose of a standby RDS (Relational Database Service) instance is to provide high availability and fault tolerance for your database. A standby instance serves as a backup or replica of the primary RDS instance and is ready to take over in the event of a failure or during maintenance activities.
Q: What is an ElastiCache cluster?
Answer: ElastiCache clusters are designed to improve application performance by providing a distributed, scalable, and highly available caching layer. They enable applications to retrieve frequently accessed data quickly, reducing the load on backend databases or other data sources. The specific configuration and size of an ElastiCache cluster can be customized to meet the needs of your application’s caching requirements.