Databases

Question 1

Do NoSQL databases perform aggregations such as SUM() or AVG()

Answer 1

No

Question 2

Do NoSQL databases scale horizontally?

Answer 2

Yes

Question 3

Is DynamoDB Highly Available across Multiple AZs out of the box?

Answer 3

Yes

Question 4

Does Dynamo DB integrate with IAM?

Answer 4

Yes

Question 5

DynamoDB is made of ____________?

Answer 5

Tables

Question 6

DynamoDB tables must have a _________?

Answer 6

Partition key

Question 7

Each DynamoDB item has________?

Answer 7

Attributes

Question 8

What is the maximum size of an item?

Answer 8

400kb

Question 9

What is a partition key in DynamoDB?

Answer 9

It acts as a primary key and must be unique for each item. It also must be diverse enough to data is distributed.

Question 10

What two primary key options are available in DynamoDB?

Answer 10

Partition Key
Partition Key + Sort Key

Question 11

When using a partition key and sort key in DynamoDB, what is the limitation?

Answer 11

The partition and sort key combination must be unique.

Question 12

What are the two table classes in DynamoDB?

Answer 12

DynamoDB standard

DynamodDB standard-IA

Question 13

What does the sort key really do in the UI?

Answer 13

Allows you to sort on a column.

Question 14

What are the capacity modes in DynamoDB?

Answer 14

Provisioned Mode

On-Demand Mode

Question 15

How often can you switch between capacity modes in DynamoDB?

Answer 15

Every 24 hours

Question 16

If you exceed your RCU or WCU in DynamodDB, what error is returned?

Answer 16

ProvisionedThroughputExceededException

Question 17

How can you deal with ProvisionedThroughputExceededException without increasing WCU or RCU?

Answer 17

Exponential Backoff

Question 18

What is the measurement for one WCU?

Answer 18

One item per second for an item up to 1kb in size.

Question 19

If you have an item that is 4.5kb in size, how many WCU is required?

Answer 19

5 .. Rounding up is required.

Question 20

What are the two kinds of reads in Dynamodb?

Answer 20

Strongly Consistent

Eventually Consistent

Question 21

What is the problem with Eventually consistent reads?

Answer 21

Old data may be returned if there is replication latency.

Question 22

What does a consistent read in DynamoDB do?

Answer 22

It reads the data after a write, but ensures that it is the most recent data.