Amazon Redshift Interview Questions and Answers

Amazon Redshift Interview Questions and Answers

Last updated on 24th Oct 2020, Blog, Interview Question

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These Amazon Redshift Interview Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your interview for the subject of Amazon Redshift . As per my experience good interviewers hardly plan to ask any particular question during your interview, normally questions start with some basic concept of the subject and later they continue based on further discussion and what you answer.we are going to cover top 100 Amazon Redshift  Interview questions along with their detailed answers. We will be covering Amazon Redshift  scenario based interview questions,Amazon Redshift  interview questions for freshers as well asAmazon Redshift  interview questions and answers for experienced. 

1.What is Amazon Redshift ?


AWS Redshift is a Cloud-based data warehouse service. Redshift is a petabyte scale, powerful and fully managed relational data warehousing service.

An Amazon Redshift data warehouse is a collection of computing resources called nodes, which are organized into a group called a cluster. Each cluster runs an Amazon Redshift engine and contains one or more databases. Amazon Redshift provides efficient storage and faster database efficiency through specific properties such as massively parallel processing, columnar data storage, and multiple encoding schemes for data compression. Redshift can connect to JDBC client applications with ODBC connections. It is based on the PostgreSQL standard.

2.Where and When Redshift can be used?


Big customers are heading towards service in the data warehouse today. Redshift can be used in different sectors, business use cases seeking a data warehouse cloud service with features such as cost savings, efficient dynamic query engine, security etc.

Clients looking for moving from on premise to cloud model, PaaS model. Traditional setup of servers, data centers for a company was a headache. This requires upfront planning, estimation, prediction of servers, type of servers etc. and eventually takes months to come to a conclusion. Any wrong estimation or decision can lead to over or short of the estimated capacity and financial loss or short of resources. Following are business use cases or industries where Redshift can be used:-

  • Consolidation of accounting data : Redshift can be used to consolidate the data to see the company’s financial position at company level. Redshift math, analytic, date functions along with user in-built functions to derive various formula and complex customized calculations with optimized performance are very valuable features for accounting
  • Build Data Lake for pricing data : Redshift’s columnar storage is best fit for time series data.
  • Supply chain management : To query and analyze huge volume of data feature like parallel processing with powerful node types make Redshift a good option

3.What is a data warehouse and how does AWS Redshift helps?


A data warehouse is designed as a warehouse where the data from the systems and other sources generated by the organization are collected and processed.

At high level data warehouse has three-tier architecture:

  • In the bottom tier, we have the tools which cleanse and collect the data.
  • In the middle level, we have tools to transform the data using the Online Analytical Processing Server.
  • At the top level, we have different tools where data analysis and data mining are carried out at the front end.

As data grows continuously in an organization and the company constantly has to update its expensive storage servers. Here AWS Redshift is generated in the cloud-based warehouses offered by Amazon where businesses store their data.

4.What are the benefits of Amazon Redshift ?


AWS Redshift has below main benefits compared to other options :

  • AWS Redshift is easy to operate : you can find a choice to build a cluster in the AWS Redshift Console. Only press and leave the rest on the Redshift computer program. Just complete the correct information and start the cluster. The cluster is now ready to be used, for example to control, track and scale Redshift.
  • Cost Effective: Because there is no need to set up, the cost of this warehouse is reduced to 1/10th.
  • Scaling of Warehouse is very easy: You just have to resize the cluster size by increasing the number of compute nodes.
  • High performance: It uses such techniques such as column storage and large simultaneous processing techniques to produce high efficiency and responsiveness times.

5.What are the factors to consider while migrating to Amazon Web Services?


Here are the factors to consider during AWS migration:

  • Operational Costs – These include the cost of infrastructure, ability to match demand and supply, transparency, and others.
  • Workforce Productivity 
  • Cost avoidance
  • Operational resilience
  • Business agility

6.Does Amazon support region based services on all services? 


No, it is not providing region-specific usage on all its services. But most of the services are region-based. 

7.What is EBS in AWS?


Elastic block storage (EBS) is a storage system that is used to store persistent data. EBS is designed to provide block-level storage volumes and to use EC2 instances for both transactions and throughput intensive workloads at any scale. 

8.How many AWS services are there in 2020?


As of September 2019, the AWS Serverless Application repository is available in the AWS GovCloud (US-East) region. With this service, the availability of services is increased to a total of 18 AWS regions across North America, South America, the EU, and the Asia Pacific. 

9.Which AWS region is the cheapest?


The US standard is the cheapest region; it is also the most established AWS region. 

10.What is the maximum size of an S3 bucket?


The maximum size of an S3 bucket is 5 terabytes.

11.What are the most popular AWS Services?


Following are the most popular AWS Services:

  • Amazon S3
  • AWS Lambda
  • Amazon Glacier
  • Amazon EC2
  • Amazon SNS
  • Amazon CloudFront
  • Amazon EBS
  • Amazon Kinesis
  • Amazon VPC
  • Amazon SQ 

12.Is AWS RDS free?


Yes, AWS RDS is a free tier. RDS helps the AWS customers to get started with the management database service in the cloud for free.  

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13.Is Amazon S3 a global service?


Yes, Amazon S3 is a global service. It provides object storage through the web interface and it uses the Amazon scalable storage infrastructure to run its global e-commerce network.

14.What are the benefits of AWS?


AWS provides services to its users at a low cost. Amazon web services are easy to use and the user should not worry about security, servers, and databases. Amazon web services have several benefits which make users rely on them.  

15.What is Amazon Web Services?


AWS stands for Amazon Web Services, which is a cloud computing platform. It is designed in such a way that it provides cloud services in the form of small building blocks, and these blocks help create and deploy various types of applications in the cloud. These sequences of small blocks are integrated to deliver the services in a highly scalable manner. 

16.What are the Main Components of AWS?  


The Key Components of AWS are:  

  • Simple Email Service: It allows you to send emails with the help of regular SMTP or by using a restful API call   
  • Route 53: It’s a DNS web service.
  • Simple Storage Device S3: It is a widely used storage device service in AWS Identity and Access Management 
  • Elastic compute cloud( EC2): It acts as an on-demand computing resource for hosting applications. EC2 is very helpful in time of uncertain workloads. 
  • Elastic Block Store: It allows you to store constant volumes of data which is integrated with EC2 and enables you to data persist. 
  • Cloud watch: It allows you to watch the critical areas of the AWS with which you can even set a reminder for troubleshooting. 

17.Explain what S3 is all about?


S3 is the abbreviation for a simple storage service. It is used for storing and retrieving data at any time and anywhere on the web. S3 makes web-scale computing easier for developers. The payment mode of S3 is available on a pay as you go basis.  

18.What is the relationship between an instance and AMI? 


Using a single AMI, you can download as many instances as you can. An instance type is used to define the hardware of the host computer for your situation. Each instance is unique and provides the facilities in computational and storage capabilities. Once you install an instance, it looks similar to a traditional host with which we can interact in the same way we do with a computer.  

19.How do we execute sql files on Redshift?


You can be done this job by using a simple Python script running on an EC2 to set up a JDBC connection to Redshift. When it is done, execute the queries in the your.SQL file

20.How to connect a private Redshift cluster?


By selecting the option NO, you access for your private IP address within the VPC. Bu doing this, you execute the public IP address. Now, the way of its accessing is through the VPC.

One more method most of the people use to connect to a private database is by using the port forwarding by a Bastion server

21.What is the redshift spectrum?


Redshift Spectrum is one of the popular features of Amazon web services. It allows you to do complex analysis of data that is stored in AWS cloud faster. The redshift spectrum is perfect for a data analyst who is performing on SQL queries in the bucket of Amazon S3. For the purpose of analysis, one can easily load data to the cluster of Amazon redshift from Amazon S3. The two major reasons for using the redshift spectrum are, it is budget-friendly as the pricing is dependable on the size of the cluster and the efforts in loading data are a bit less than any other source. If we talk about the spectrum of redshift it is a kind of bridge for providing an interface between redshift and S3 data.

22.What problems have you faced while working with Amazon Redshift?


  • Majority of the people facing the problem of the queries which are very slow and take a lot of time answering it.
  • Another problem that is seemed is on the dashboard. The dashboard is too slow.
  • Another problem in the Amazon Redshift is “black box”. It is very difficult to observe ‘what’s going on’.

23.What are clusters in Redshift? How do I create and delete a cluster in AWS redshift ?


Computing resources in Amazon Redshift data warehouse are called nodes which are further arranged in a group known as a cluster.

This cluster contains at least one database and it works on Amazon Redshift engine.

24.Explain what AWS is?


AWS stands for Amazon Web Service; it is a collection of remote computing services also known as a cloud computing platform.  This new realm of cloud computing is also known as IaaS or Infrastructure as a Service.

25.Mention what the key components of AWS are?


The key components of AWS are

  • Route 53:A DNS web service
  • Simple E-mail Service:It allows sending e-mail using RESTFUL API call or via regular SMTP
  • Identity and Access Management:It provides enhanced security and identity management for your AWS account
  • Simple Storage Device or (S3):It is a storage device and the most widely used AWS service
  • Elastic Compute Cloud (EC2): It provides on-demand computing resources for hosting applications. It is handy in case of unpredictable workloads
  • Elastic Block Store (EBS):It offers persistent storage volumes that attach to EC2 to allow you to persist data past the lifespan of a single Amazon EC2 instance
  • CloudWatch: To monitor AWS resources, It allows administrators to view and collect key Also, one can set a notification alarm in case of trouble.

26.Explain what S3 is?


S3 stands for Simple Storage Service. You can use the S3 interface to store and retrieve any amount of data, at any time and from anywhere on the web.  For S3, the payment model is “pay as you go.”

27.What is AMI?


AMI stands for Amazon Machine Image.  It’s a template that provides the information (an operating system, an application server, and applications) required to launch an instance, which is a copy of the AMI running as a virtual server in the cloud.  You can launch instances from as many different AMIs as you need.

28.Mention what the relationship between an instance and AMI is?


From a single AMI, you can launch multiple types of instances.  An instance type defines the hardware of the host computer used for your instance. Each instance type provides different computer and memory capabilities.  Once you launch an instance, it looks like a traditional host, and we can interact with it as we would with any computer.

29.What does an AMI include?


An AMI includes the following things

  • A template for the root volume for the instance
  • Launch permissions decide which AWS accounts can avail the AMI to launch instances
  • A block device mapping that determines the volumes to attach to the instance when it is launched

30.How can you send a request to Amazon S3?


Amazon S3 is a REST service, and you can send a request by using the REST API or the AWS SDK wrapper libraries that wrap the underlying Amazon S3 REST API.

31.Mention what the difference between Amazon S3 and EC2 is?


The difference between EC2 and Amazon S3 is that

It is a cloud web service used for hosting your applicationIt is a data storage system where any amount of data can be stored
It is like a huge computer machine which can run either Linux or Windows and can handle application like PHP, Python, Apache or any databasesIt has a REST interface and uses secure HMAC-SHA1 authentication keys

32.How many buckets can you create in AWS by default?


By default, you can create up to 100 buckets in each of your AWS accounts.

33.Explain can you vertically scale an Amazon instance? How?


Yes, you can vertically scale on Amazon instance. For that

  • Spin up a new larger instance than the one you are currently running
  • Pause that instance and detach the root webs volume from the server and discard
  • Then stop your live instance and detach its root volume
  • Note the unique device ID and attach that root volume to your new server
  • And start it again

34.Explain what T2 instances are?


T2 instances are designed to provide moderate baseline performance and the capability to burst to higher performance as required by the workload.

35.In VPC with private and public subnets, database servers should ideally be launched into which subnet?


With private and public subnets in VPC, database servers should ideally launch into private subnets.

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36.Mention what the security best practices for Amazon EC2 are?


For secure Amazon EC2 best practices, follow the following steps

  • Use AWS identity and access management to control access to your AWS resources
  • Restrict access by allowing only trusted hosts or networks to access ports on your instance
  • Review the rules in your security groups regularly
  • Only open up permissions that you require
  • Disable password-based login, for example, launched from your AMI

37.Explain how the buffer is used in Amazon web services?


The buffer is used to make the system more robust to manage traffic or load by synchronizing different components.  Usually, components receive and process the requests in an unbalanced way. With the help of a buffer, the components will be balanced and will work at the same speed to provide faster services.

38.What are key-pairs in AWS?


Key-pairs are secure login information for your virtual machines. To connect to the instances, you can use key-pairs which contain a public-key and private-key.

39.What are the different types of instances?


Following are the types of instances:

  • General purpose
  • Computer Optimized
  • Memory Optimized
  • Storage Optimized
  • Accelerated Computing

40.Is the property of broadcast or multicast supported by Amazon VPC?


  No, currently Amazon VPI does not provide support for broadcast or multicast.

41.How many Elastic IPs are allowed to be created by AWS?


5 VPC Elastic IP addresses are allowed for each AWS account.

42.Explain default storage class in S3?


The default storage class is a Standard frequently accessed.

43.What are the roles?


Roles are used to providing permissions to entities which you can trust within your AWS account. Roles are very similar to users. However,  with roles, you do not require to create any username and password to work with the resources.

44.What are the edge locations?


Edge location is the area where the contents will be cached. So, when a user is trying to accessing any content, the content will automatically be searched in the edge location.

45.What is VPC?


VPC stands for Virtual Private Cloud. It allows you to customize your networking configuration. It is a network which is logically isolated from another network in the cloud. It allows you to have your IP address range,  internet gateways, subnet and security groups.

46.Explain snowball?


Snowball is a data transport option. It used source appliances to a large amount of data into and out of AWS. With the help of snowball, you can transfer a massive amount of data from one place to another. It helps you to reduce networking costs.

47.What is a redshift?


Redshift is a big data warehouse product. It is fast and powerful, fully managed data warehouse service in the cloud.

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48.What are the advantages of auto-scaling?


Following are the advantages of autoscaling

  • Offers fault tolerance
  • Better availability
  • Better cost management

49.Can you establish a Peering connection to a VPC in a different region?


No, It’s only possible between VPCs in the same region.

50.What is SQL?


Simple Queues Services also known as SQL. It is distributed queuing service which acts as a mediator for two controllers.

51.How many subnets can you have per VPC?


You can have 200 subnets per VPC.

52.DNS  and Load Balancer service comes under which type of cloud service?


DNS and Load Balancer and DNS services come under IAAS-storage cloud service.

53.What is the role of AWS CloudTrail?


CloudTrail is a specially designed tool for logging and tracking API calls. It helps to audit all S3 bucket accesses.

54.When EC2 officially launched?


  EC2 officially launched in the year 2006.

55.What is SimpleDB?


SimpleDB is a data repository of structure record which encourages data doubts and indexing both S3 and EC2are called SimpleDB.

56.Explain Amazon ElasticCache?


Amazon Elasticache is a web service which makes it easy to deploy, scale and store data in the cloud.

57.What is AWS Lambda?


Lambda is an Amazon compute service which allows you to run code in the  AWS Cloud without managing servers.

58.Name the types of AMI provided by AWS?


The types of AMI provided by AWS are:

  • Instance store backed
  • EBS backed

59.Name the AWS service exists only to redundantly cache data and images?


AWS Edge locations are service which redundantly cache data and images.

60.Explain Geo Restriction in CloudFront?


A Geo-restriction feature helps you to prevent users of specific geographic locations from accessing content which you’re distributing through a CloudFront web distribution.

61.What is Amazon EMR?


EMR is a surviving cluster stage which helps you to interpret the working of data structures before the intimation.  Apache Hadoop and Apache Spark on the Amazon Web Services helps you to investigate a large amount of data. You can prepare data for the analytics goals and marketing intellect workloads using Apache Hive and using other relevant open source designs.

62.What is boot time taken for the instance store backed AMI?


The boot time for an Amazon instance store-backend AMI is less than 5 minutes.

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