RDS & DynamoDB

Question 1

eventually consistent vs strongly consistent reads

Answer 1

“Strongly consistent returns the most up to date data but may take longer to get >1sec
eventually consistent returns whatever is currently in the system which may not include recent updates”

Question 2

What is a CNAME used for?

Answer 2

“Canonical Name
Points one domain address to another
often a sub domain (ft.mydomain.com) to it’s main domain(www.mydomain.com)”

Question 3

What is the failover mechanism feature?

Answer 3

A safety feature that automatically changes the DNS CNAME record of DB instances to point to backup instances in the event of failure

Question 4

What is Aurora?

Answer 4

“A MySQL and PostreSQL compatible relational database built for the cloud
High performance and availability at 1/10th the cost”

Question 5

What is provisioned throughput capacity?

Answer 5

“A setting that needs to be configured when creating a DynamoDB
Writes are more expensive than reads
Because of this read heavy applications work well on DynamoDB”

Question 6

What is a primaryKey in DynamoDB?

Answer 6

“Primary Key is either
Partition key
Partition key and sort key (essentialy a way to improve look up potential)”

Question 7

What causes DynamoDB to reject requests?

Answer 7

“Tables are aranged poorly so that queries overburden one partition too much
Adaptive capacity is a feature that borrows capacity from other partitions, mitigating poor table design for most cases”

Question 8

What is the RCU and WCU limits per partition?

Answer 8

“Read capacity units - 3000

Write capacity units - 1000”

Question 9

In DynamoDB what is a GSI?

Answer 9

“Global Secondary Index
A feature to reduce the use of scan and filerExpression on the data
Allows you to query a table by a row that is not the primary key
GSI clones your primary table using your new Partition Key, but keeps these two tables in sync”

Question 10

Which database service supports schema changes?

Answer 10

Aurora

Question 11

What is the Elasticache Service?

Answer 11

Caches all th ecommon queries so data sets will be fetched from the cache rather than the database

Question 12

Standby vs Read Replica

Answer 12

“uses synchronous replication between primary and standby systems
read replicas use asynchronous replication”

Question 13

What is Multi-region replication or Global tables?

Answer 13

“AWS managed multi-region, multi-master database
Every region has their own table and AWS ensures that they are synced within 3 seconds
Only enabled on tabels with
no data (empty table)
tables with the same name and structure”

Question 14

transporting from redshift to S3 within VPC

Answer 14

create and configure S3 VPC endpoint. enable redshift enhanced VPC routing feature.

Question 15

What is Redshift?

Answer 15

An AWS columnar datastore

Question 16

What feature creates copies of Redshift in other regions

Answer 16

“Cross-Region Snapshot

copies can be created automatically or manually”

Question 17

What feature provides enhanced availability an durability for RDS?

Answer 17

“RDS multi-az deployment
Amazon automatically creates a primary DB instance and synchronously replicates the data to a standby instance in a different AZ”

Question 18

What is DynamoDB streams?

Answer 18

An ordered flow of information about changes to items in a DynamoDB table

Question 19

process of automated backup of Amazon RDS

Answer 19

“storage volume snapshot of database instance is created once daily
for restoring at a specific point in time best practice is to capture transaction logs every 5 minutes in an S3 bucket”

Question 20

What Redshift feature ensures all traffic to and from it are within the VPC?

Answer 20

Enhanced VPC routing