Databases

Question 1

What are the benefits of databases?

Answer 1

• structure the data
• build indexes to efficiently query/search through the data
• define relationships between your datasets
• flexibility, scalability, high-performance, highly funtctional

Question 2

Name a few examples of databases

Answer 2

key-value, document, graph, in-memory, search database

Question 3

What do the AWS database-services provide?

Answer 3

• quick provisioning, high availability, vertical and horizontal scaling
• automated backup & restore, Operations, Upgrades
• Operating System Patching is handled by AWS
• Monitoring, alerting

Question 4

Can you run a database on EC2 without using the database-services?

Answer 4

Yes, but you must handle yourself the resiliency, backup, patching, high availability, fault tolerance, scale etc.

Question 5

Name the six engines of Amazon RDS

Answer 5

• Aurora
• PostgreSQL
• MySQL
• MariaDB
• Oracle Database
• SQL Server

Question 6

Name three benefits of RDS

Answer 6

• automated backups
• database snapshots
• automatic host replacement

Question 7

What does RDS provide?

Answer 7

• automated provisioning, OS patching
• Continuous backups and restore to specific timestamp (Point in Time Restore)!
  
  • Monitoring dashboards
• Read replicas for improved read performance
• Multi AZ setup for DR (Disaster Recovery)
• Maintenance window for upgrades)
• Scaling capability (vertical and horizontal)
• Storage backed by EBS (gp2 or io!)

Question 8

Can you SSH into your RDS database instance?

Answer 8

No

Question 9

What do you know about Amazon Aurora?

Answer 9

• PostgreSQL and MySQL are supported
• 5 times performance improvement over MySQL on RDS
• cost 20% more than RDS but is more efficient

Question 10

What do you know about Amazon Dynamo DB

Answer 10

• noSQL database -> key-value-pair
• millions of requests per second
• low latency
• integrated with IAM for security, authorization and administration
• low cost and auto scaling capabilities

Question 11

What do you know about DynamoDB Accelerator - DAX?

Answer 11

• fully managed in-memory cache for DynamoDB
• 10x performance improvement - single-digit millisecond latency to microseconds latency
• secure, highly scalable & highly available
• difference with ElastiCache at the CCP level: DAX is only used for and is integrated with DynamoDB, while ElastiCache can be used for other databases

Question 12

What do you know about Redshift?

Answer 12

• OLAP - online analytical processing (analytics and data warehousing)
• load data once every hour, not every second
• 10x better performance than other data warehouse, scale to PBs of data
• columnar storage of data (instead of row based)
• massively parallel query execution (MPP), highly available
• pay as you go based on the instances provisioned
• has a sql interface for performing the queries
• BI tools such as AWS Quicksight or Tableau integrate with it

Question 13

What do you know about Amazon Elastic MapReduce (EMR)

Answer 13

• helps creating Hadoop clusters (Big Data) to analyze and process vast amount of data
• the clusters can be made of hundreds of EC2 instances
• take care of all the provisioning and configuration
• use cases: data processing, machine learning, web indexing, big data…

Question 14

What do you know about Athena?

Answer 14

• fully serverless database with SQL capabilities
• used to query data in S3
• pay per query
• output results back to S3
• secured through IAM
• use case: one-time SQL queries, serverless queries on S3, log analytics

Question 15

What do you know about Amazon QuickSight?

Answer 15

• serverless machine learning-powered business intelligence service to create interactive dashboards
• fast automatically scalable, embeddable, with per-session pricing
• integrated with RDS, Aurora, Athena, Redshift, S3

Question 16

Name four use cases for Amazon QuickSight

Answer 16

• business analytics
• building visualizations
• perform ad-hoc analysis
• get business insights using data

Question 17

What do you know about DocumentDB

Answer 17

• is the same for MongoDB (NoSQL database) as Aurora for PostgreSQL/MySQL
• MongoDB is used to store, query and index JSON data
• similar deployment concepts as Aurora
• fully managed, highly available with replication 3 AZ
• automatically scales to workloads with millions of requests per second

Question 18

What do you know about Amazon Neptune?

Answer 18

• fully managed graph database
• highly available across 3 AZs with up to 15 read replicas
• can store up to billions of relations and query the graph with milliseconds latency
• great for knowledge graphs (wikipedia), fraud detection, recommendation engines, social networking

Question 19

What do you know about Amazon Quantum Ledger Database (QLDB)?

Answer 19

• a ledger is a book recording financial transactions
• fully managed, serverless, high available, replication across 3 AZs
• used to review history of all the changes made to your application data over time
• immutable system: no entry can be removed or modified, cryptographically verifiable

Question 20

What do you know about Amazon Managed Blockchain?

Answer 20

• blockchain make it possible to build applications where multiple parties can execute transactions without the need for a trusted, central authority
• is a managed service to join public blockchain networks or create your own scalable private network
• compatible with the frameworks Hyperledger Fabric & Ethereum

Question 21

What do you know about AWS Glue?

Answer 21

• managed extract, transform and load (ETL) service
• useful to prepare and transform data for analytics
• fully serverless service
• glue data catalog catalog of datasets: can be used by Athena, Redshift, EMR

Question 22

What do you know about Database Migration Service (DMS)?

Answer 22

• quickly and securely migrate databases to AWS, resilient, self healing
• the source database remains available during the migration
• supports homogeneous and heterogeneous migrations