Database & Analytics

Question 1

Databases

Answer 1

Is an organized collection of structured information, or data, typically stored electronically in a computer system.

• You build indexes to efficiently query / search through the data
• You define relationships between your datasets

Question 2

Relational Databases

Answer 2

Is a collection of information that organizes data in predefined relationships where data is stored in one or more tables of columns and rows

• Can use the SQL language to perform queries / lookups

Question 3

NoSQL Databases

Answer 3

• NoSQL databases are purpose built for specific data models and have flexible schemas for building modern applications
• Benefits: Flexibility, Scalability, High-performance, Highly functional
• Examples: Key-value, document, graph, in-memory, search databases

Question 4

NoSQL data example: JSON

Answer 4

• JSON = JavaScript Object Notation
• JSON is a common form of data that fits into a NoSQL model
• Data can be nested
• Fields can change over time

Question 5

Databases & Shared Responsibility on AWS

Answer 5

• AWS offers use to manage different databases
• Benefits include:
• Quick Provisioning, High Availability, Vertical and Horizontal Scaling
• Automated Backup & Restore, Operations, Upgrades
• Operating System Patching is handled by AWS
• Monitoring, alerting

Question 6

AWS RDS

Answer 6

• RDS stands for Relational Database Service
• It’s a managed DB service for DB use SQL as a query language.
• It allows you to create databases in the cloud that are managed by AWS
• Postgres
• MySQL
• MariaDB
• Oracle
• Microsoft SQL Server
• Aurora (AWS Proprietary database)

Question 7

Advantage over using RDS versus deploying
DB on EC2

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 windows for upgrades
• Scaling capability (vertical and horizontal)
• Storage backed by EBS (gp2 or io1)

Question 8

Amazon Aurora

Answer 8

• Aurora is a proprietary technology from AWS (not open sourced)
• PostgreSQL and MySQL are both supported as Aurora DB
• Aurora is “AWS cloud optimized”, better performance than RDS
• Aurora storage automatically grows in increments of 10GB, up to 64 TB.
• Aurora costs more than RDS (20% more) – but is more efficient

Question 9

RDS Deployments: Read Replicas, Multi-AZ

Answer 9

• Read Replicas:
• Scale the read workload of your DB
• Can create up to 5 Read Replicas
• Data is only written to the main DB

• Multi-AZ:
• Failover in case of AZ outage (high availability)
• Data is only read/written to the main database
• Can only have 1 other AZ as failover

Question 10

RDS Deployments: Multi-Region

Answer 10

• Multi-Region (Read Replicas)
• Disaster recovery in case of region issue
• Local performance for global reads
• Replication cost

Question 11

Amazon ElastiCache

Answer 11

• ElastiCache is to get managed Redis or Memcached
• Caches are in-memory databases with high performance, low latency
• Helps reduce load off databases for read intensive workloads
• You want to save the queries somewhere else,so that they’re very readily available.

Question 12

DynamoDB

Answer 12

• Fully Managed Highly available with replication across 3 AZ
• NoSQL database /// Serverless
• Automatically scales up and down to adjust for capacity and maintain performance
• Millions of requests per seconds, 100s of TB of storage
• Single-digit millisecond latency – low latency retrieval

Question 13

DynamoDB – type of data

Answer 13

• DynamoDB is a key/value database

Question 14

DynamoDB Accelerator - DAX

Answer 14

• Fully Managed in-memory cache for
DynamoDB
• 10x performance improvement – single- digit millisecond latency to microseconds
latency
• Secure, highly scalable & highly available

Question 15

DynamoDB – Global Tables

Answer 15

• Make a DynamoDB table accessible with low latency in multiple-regions
• Active-Active replication (read/write to any AWS Region)

Question 16

Redshift

Answer 16

• Relational database
• Redshift is based on PostgreSQL, but it’s not used for OLTP
• It’s OLAP – online analytical processing (analytics and data warehousing)
Columnar storage of data (instead of row based)
• Load data once every hour, not every second

Question 17

Amazon EMR “Elastic MapReduce”

Answer 17

• EMR helps creating Hadoop clusters (Big Data) to analyze and process vast amount of data
• The clusters can be made of hundreds of EC2 instances
• Use cases: data processing, machine learning, web indexing, big data

Question 18

Amazon Athena

Answer 18

• Serverless query service to analyze data stored in Amazon S3
• Uses standard SQL language
• Use cases: Business intelligence / analytics / reporting, analyze

• Exam Tip: analyze data in S3 using serverless SQL, use Athena

Question 19

Amazon QuickSight

Answer 19

• Serverless machine that allows you to create dashboards on your databases so we can visually represent your data and show your business users the insights they’re looking for
• Fast, automatically scalable, embeddable, with per-session pricing
• Use cases: • Business analytics • Building visualization

Question 20

DocumentDB

Answer 20

• DocumentDB is the same for MongoDB (which is a NoSQL database)
• MongoDB is used to store, query, and index JSON data
• Fully Managed, highly available with replication across 3 AZ
• Aurora storage automatically grows in increments of 10GB, up to 64 TB.
• Automatically scales to workloads with millions of requests per seconds

Question 21

Amazon Neptune

Answer 21

• Fully managed graph database
• A popular graph dataset would be a social network
• Highly available across 3 AZ, with up to 15 read replicas
• Build and run applications working with highly connected datasets
• Can store up to billions of relations

Question 22

Amazon QLDB

Answer 22

• QLDB stands for ”Quantum Ledger Database”
• Centralized component
• A ledger is a book recording financial transactions
• Fully Managed, Serverless, High available, Replication across 3 AZ
• Used to review history of all the changes made to your application data over time
• NoSQL

Question 23

Amazon Managed Blockchain

Answer 23

• Blockchain makes it possible to build applications where multiple parties can execute transactions without the need for a trusted, central authority
• Amazon Managed Blockchain is a managed service to: • Join public blockchain networks
• Or create your own scalable private network

Question 24

AWS Glue

Answer 24

• Fully serverless service
• Managed extract, transform, and load (ETL) service
• Useful to prepare and transform data for analytics

• Glue Data Catalog: catalog of datasets

Question 25

DMS – Database Migration Service

Answer 25

• Quickly and securely migrate databases
to AWS, resilient, self healing
• The source database remains available
during the migration

Question 26

Difference between relational and non relational db

Answer 26

The difference between DynamoDB and, say, RDS is that DynamoDB will have all the data living within one single table, and there’s no way to join it with another table.