DynamoDB

Question 1

DynamoDB 3 most common data types

Answer 1

B (Binary), N (Number), S (String)

Question 2

What are table rows and columns called?

Answer 2

Items (rows) and Attributes (columns)

Question 3

What is when DynamoDB slices your table up into smaller chunks of data? (this speeds up reads for very large tables)

Answer 3

A Partition

Question 4

When does DynamoDB create a partition?

Answer 4

• Every 10 GB of Data or
• When you exceed RCUs (3000) or WCUs (1000) limits for a single partition
• When DynamoDB sees a pattern of a hot partition, it will split that partition in an attempt to fix the issue

Question 5

What are the two types of primary key?

Answer 5

• Simple Primary Key (Using only a Partition Key)

- Composite Primary Key (Using both a Partition and Sort Key)

Question 6

Partition Key is also known as…

Answer 6

HASH

Question 7

Sort Key is also known as…

Answer 7

RANGE

Question 8

When creating a Simple Primary Key, what value must be unique?

Answer 8

the Partition Key

Question 9

When creating a Composite Primary Key, what combination must be unique?

Answer 9

the combined Partition and Sort Key must be unique

Question 10

What DynamoDB API calls support transaction?

Answer 10

via the TransactWriteItems and TransactGetItems API calls

Question 11

What is the name of the feature that allows to set up a Lambda function triggered every time data is modified in a table to react to changes?

Answer 11

DynamoDB Streams

Question 12

What two types of Indexes does DynamoDB have?

Answer 12

LSI - Local Secondary Index (supports strongly or eventual consistency reads)

GSI - Global Secondary Index (cannot provide strong consistency)

Question 13

DynamoDB two capacity modes are…

Answer 13

Provisioned and On-Demand

Question 14

What is the name of the maximum amount of capacity your application is allowed to read or write per second from a table or index?

Answer 14

Provisioned Throughput Capacity

Question 15

The two methods of retrieving items?

Answer 15

scan and query

(Scan: Scans through all items in a table and then returns one or more items through filters. Avoid using this)

(Query: Find items based on primary key values)

Question 16

How often can you switch between DynamoDB capacity modes?

Answer 16

You can switch between these modes once every 24 hours

Question 17

This is a fully managed in-memory write through cache for DynamoDB that runs in a cluster

Answer 17

DynamoDB Accelerator (DAX)

Question 18

How do you calculate Reads (RCU)?

Answer 18

A read capacity unit represents: one strongly consistent read per second, or two eventually consistent reads per second, for an item up to 4 KB in size

How to calculate RCUs for strong

• Round data up to nearest 4
• Divide data by 4
• Times by number of reads

How to calculate RCUs for eventual

• Round data up to nearest 4
• Divide data by 4
• Times by number of reads
• Divide the final number by 2
• Round up to the nearest whole number

Question 19

How do you calculate Writes (Writes)?

Answer 19

A write capacity unit represents: one write per second, for an item up to 1 KB

How to calculate Writes

• Round data up to nearest 1
• Times by number of writes