AWS Database Interview Questions & Answers

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AWS Database Interview Questions

    1. Question 1. What Do You Know About The Amazon Database?

      Answer :

      Amazon database is one of the Amazon Web Services that offers managed database along with managed service and NoSQL. It is also a fully managed petabyte-scale data warehouse service and in-memory caching as a service. There are four AWS database services, the user can choose to use one or multiple that meet the requirements. Amazon database services are – DynamoDB, RDS, RedShift, and Elastic ache.

    2. Question 2. Explain Amazon Relational Database?

      Answer :

      Amazon relational database is a service that helps users with a number of services such as operation, lining up, and scaling an on-line database within the cloud. It automates the admin tasks such as info setup, hardware provisioning, backups, and mending. Amazon relational database provides users with resizable and cost-effective capability. By automating the tasks, it saves time and thus let user concentrate on the applications and provide them high availableness, quick performance, compatibility, and security.

      There are a number of AWS RDS engines, such as:

      • Mysql
      • Oracle
      • PostgreSQL
      • SQL Server
      • MariaDB
      • Amazon Aurora

    3. Question 3. What Are The Features Of Amazon Database?

      Answer :

      Following are the important features of Amazon Database:

      • Easy to administer
      • Highly scalable
      • Durable and reliable
      • Faster performance
      • Highly available
      • More secure
      • Cost-effective

    4. Question 4. Which Of The Aws Db Service Is A Nosql Database And Server-less, And Delivers Consistent Single-digit Millisecond Latency At Any Scale?

      Answer :

      Amazon DynamoDB.

    5. Question 5. What Is The Key-value Store?

      Answer :

      Key-value store is a database service which facilitates the storing, updating, and querying of the objects which are generally identified with the key and values. These objects consist of the keys and values which constitutes the actual content that is stored.

    6. Question 6. What Is Dynamodb?

      Answer :

      DynamoDB is a NoSQL database service that provides an inevitable and faster performance. DynamoDB is superintendent and offers a high level of scalability. DynamoDB makes users not to worry about the configuration, setup, hardware provisioning, throughput capacity, replication, software patching or cluster scaling. It helps users in offloading the scaling and operating distributed databases to AWS.

    7. Question 7. List Some Of The Benefits Of Using Amazon Dynamodb?

      Answer :

      Amazon DynamoDB is the NoSQL service that provides a number of benefits to the users.

      Some of the benefits of AWS DynamoDB are:–

      • Being a self-managed service, DynamoDB doesn’t require the experts for setup, installation, cluster etc.
      • It provides inevitable and faster performance.
      • It is highly scalable, available, and durable.
      • It provides very high throughput at the low latency.
      • It is highly cost-effective.
      • It supports and allows the creation of dynamic tables with multi-values attributes i.e. it’s flexible in nature.

    8. Question 8. What Is A Dynamodbmapper Class?

      Answer :

      The mapper class is the entry point of the DynamoDB. It allows users to enter the DynamoDB and access the endpoint. DynamoDB mapper class helps users access the data stored in various tables, then execute queries, scan them against the tables, and perform CRUD operations on the data items.

    9. Question 9. What Are The Data Types Supported By Dynamodb?

      Answer :

      DynamoDB supports different types of data types such as collection data types, scalar data types, and even null values.

      Scalar Data Types – The scalar data types supported by DynamoDB are:

      • Binary
      • Number
      • Boolean
      • String

      Collection Data Types – The collection data types supported by DynamoDB are:

      • Binary Set
      • Number Set
      • String Set
      • Heterogeneous Map
      • Heterogeneous List

    10. Question 10. What Do You Understand By Dynamodb Auto Scaling?

      Answer :

      DynamoDB Auto scaling specifies its specialized feature to automatically scale up and down its own read and write capacity or global secondary index.

    11. Question 11. What Is A Data Warehouse And How Aws Redshift Can Play A Vital Role In The Storage?

      Answer :

      A data warehouse can be thought of a repository where the data generated from the company’s systems and other sources is collected and stored. So a data warehouse has three-tier architecture:

      • In the bottom tier, we have the tools which cleanse and collect the data.
      • In the middle tier, we have tools which transform the data using Online Analytical Processing Server.
      • In the top tier, we have different tools where data analysis and data mining is performed at the front end.

      Setting up and managing a data warehouse involves a lot of money as the data in an organization continuously increases and the organization has to continuously upgrade their data storage servers. So here AWS RedShift comes into existence where the companies store their data in the cloud-based warehouses provided by Amazon.

    12. Question 12. What Is Amazon Redshift And Why Is It Popular Among Other Cloud Data Warehouses?

      Answer :

      Amazon RedShift is a fast and scalable data warehouse which is easy to use and is cost effective to manage all the organization’s data. The database is ranged from gigabytes to 100’s of petabyte of cloud data storage. A person does not need knowledge of any programming language to use this feature, just upload the cluster and tools which are already known to the user he can start using RedShift.

      AWS RedShift is popular due to the following reasons:

      1. AWS RedShift is very easy to use: In the console of AWS RedShift, you will find an option of creating a cluster. Just click on that and leave the rest on the machine programming of RedShift. Just fill the correct details as asked and launch the cluster. Now the cluster is ready to be used as RedShift automated most of the task like managing, monitoring and scaling.
      2. Scaling of Warehouse is very easy: You just have to resize the cluster size by increasing the number of compute nodes.
      3. RedShift gives 10x times better and fast performance: It makes use of specific strategies like columnar storage and massive parallel processing strategies to deliver high throughput and response time.
      4. Economical: As it does not require any setup so cost reduces down to 1/10th of the traditional data warehouse.

    13. Question 13. What Is Redshift Spectrum?

      Answer :

      The RedShift Spectrum allows you to run queries alongside petabyte of data which is unstructured and that too with no requirement of loading ETL. Spectrum scales millions of queries and allows you to allocate and store the data wherever you want and whatever the type of format is suitable for you.

    14. Question 14. What Is A Leader Node And Compute Node?

      Answer :

      In a leader node the queries from the client application are received and then the queries are parsed and the execution plan is developed. The steps to process these queries are developed and the result is sent back to the client application.

      In a compute node the steps assigned in the leader node are executed and the data is transmitted. The result is then sent back to the leader node before sending it to the client application.

    15. Question 15. How To Load Data In Amazon Redshift?

      Answer :

      Amazon DynamoDB, Amazon EMR, AWS Glue, AWS Data Pipeline are some of the data sources by which you can load data in RedShift data warehouse. The clients can also connect to RedShift with the help of ODBC or JDBC and give the SQL command ‘insert’ to load the data.

    16. Question 16. Mention The Database Engines Which Are Supported By Amazon Rds?

      Answer :

      The database engines that are supported by Amazon RDS are Amazon Aurora, Mysql, MariaDB, Oracle, SQL Server, and PostgreSQL database engine.

    17. Question 17. What Is The Work Of Amazon Rds?

      Answer :

      When a user wants to set up a relational database then Amazon RDS is used. It provisions the infrastructure capacity that a user requests to install the database software. Once the database is set up and functional RDS automates the tasks like patching up of the software, taking the backup of the data and management of synchronous data replication with automatic failover.

    18. Question 18. What Is The Purpose Of Standby Rds Instance?

      Answer :

      The main purpose of launching a standby RDS instance is to prevent the infrastructure failure (in case failure occurs) so it is stored in a different availability zone which is a totally different infrastructure physically and independent.

    19. Question 19. Are Rds Instances Upgradable Or Down Gradable According To The Need?

      Answer :

      Yes, you can upgrade the RDS instances with the help of following command: modify-db-instance. If you are unable to detect the amount of CPU needed to upgrade then start with db.m1.small DB instance class and monitor the utilization of CPU with the help of tool Amazon Cloud Watch Service.

    20. Question 20. What Is Amazon Elastic Ache?

      Answer :

      Amazon Elastic ache is an in-memory key-value store which is capable of supporting two key-value engines – Redis and Memcached. It is a fully managed and zero administrations which are hardened by Amazon. With the help of Amazon Elastic ache, you can either build a new high-performance application or improve the existing application. You can find the various application of Elastic ache in the field of Gaming, Healthcare, etc.

    21. Question 21. What Is The Use Of Amazon Elastic Ache?

      Answer :

      The performance of web applications could be improved with the help of the caching of information that is used again and again. The information can be accessed very fast using in-memory-caching. With Elastic ache there is no need of managing a separate caching server. You can easily deploy or run an open source compatible in-memory data source with high throughput and low latency.

    22. Question 22. What Are The Benefits Of Amazon Elastic Ache?

      Answer :

      There are various benefits of using Amazon Elastic ache some of which are discussed below:

      • The cache node failures are automatically detected and recovered.
      • It can be easily integrated with other AWS so as to provide a high performance and secured in-memory cache.
      • As most of the data is managed by Elastic ache such as setup, configuration, and monitoring so that the user can focus on other high-value applications.
      • The performance is enhanced greatly as it only supports the applications which require a very less response time.
      • The Elastic ache can easily scale itself up or scale down according to the need.

    23. Question 23. Explain The Types Of Engines In Elastic Ache?

      Answer :

      There is two type of engine supported in Elastic ache: Memcached and Redis.

      Memcached:

      It is a popular in-memory data store which the developers use for the high-performance cache to speed up applications. By storing the data in memory instead of disk Memcached can retrieve the data in less than a millisecond. It works by keeping every value of the key for every other data to be stored and uniquely identifies each data and lets Memcached quickly find the record.

      Redis:

      Today’s applications need low latency and high throughput performance for real-time processing. Due to the performance, simplicity, and capability of redis, it is most favored by the developers. It provides high performance for real-time apps and sub-millisecond latency. It supports complex data types i.n. string, hashes, etc and has a backup and restore capabilities. While Memcached supports key names and values up to 1 MB only redis supports up to 512 MB.

    24. Question 24. Is It Possible To Run Multiple Db Instances For Free For Amazon Rds?

      Answer :

      Yes, it is possible to run more than one Single-AZ micro DB instance for Amazon RDS and that’s for free. However, if the usage exceeds 750 instance hours across all the RDS Single-AZ micro DB instances, billing will be done at the standard Amazon RDS pricing across all the regions and database engines.

      For example, consider we are running 2 Single-AZ micro DB instances for 400 hours each in one month only; the accumulated usage will be 800 instance hours from which 750 instance hours will be free. In this case, you will be billed for the remaining 50 hours at the standard pricing of Amazon RDS.

    25. Question 25. Which Aws Services Will You Choose For Collecting And Processing E-commerce Data For Real-time Analysis?

      Answer :

      I’ll use DynamoDB for collecting and processing e-commerce data for real-time analysis. DynamoDB is a fully managed NoSQL database service that can be used for any type of unstructured data. It can even be used for the e-commerce data taken from e-commerce websites. On this retrieved e-commerce data, analysis can be then performed using RedShift. Elastic MapReduce can also be used for analysis but we’ll avoid it here as real-time analysis if required.

    26. Question 26. What Will Happen To The Db Snapshots And Backups If Any User Deletes Db Instance?

      Answer :

      When a dB instance is deleted, the user receives an option of making a final dB snapshot. If you will do that it will restore your information from that snapshot. AWS RDS keeps all these dB snapshots together that are created by the user along with the all other manually created dB snapshots when the dB instance is deleted. At the same time, automated backups are deleted while manually created dB snapshots are preserved.

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