DynamoDB

Question 1

What is the maximun size of a row in DynamoDB?

Answer 1

400kb

Question 2

What are the two options for partition keys in DynamoDB?

Answer 2

1. Partition Key (Hash)
2. Partition Jey + Sort Key (Hash + Range)

Question 3

What are the two read/write capacity modes for DynamoDB?

Answer 3

1. Provisioned Mode
2. On-Demand Mode

Question 4

One Write Capacity Unit is the equivalent of _ write per second for an item up to _KB in size

Answer 4

One Write Capacity Unit is the equivalent of one write per second for an item up to 1 KB in size

Question 5

One Read Capacity Unit is the equivalent of _ strongly consistend read per second, or _ eventually consistered reads per second for an item up to _KB in size

Answer 5

One Read Capacity Unit is the equivalent of one strongly consistend read per second, or one eventually consistered reads per second for an item up to 4KB in size

Question 6

How are WCU and RCU’s distributed for Dynambo DB

Answer 6

Eventy across partitions

Question 7

What are 3 possible solutions to DynamoDB throttling?

Answer 7

1. Exponential backoff
2. Distribute parition keys more
3. Use DynamoDB Accelerator (DAX)

Question 8

What is the difference between a ProjectionExpression and a FilterExpression?

Answer 8

ProjectionExpression determines what attributes will be returned from a query whereas a FilterExpression filters out results AFTER the query is commpleted based on non-key attributes.

Question 9

If part of a DynamoDB batch operation fails, what happens?

Answer 9

A list of “UnprocessedItems” will be returned

Question 10

What operations can be done as Batch operations in DynamoDB and how many items can be done at once?

Answer 10

Up to 25 PutItem and DeleteItem can be batched

Question 11

What is the difference between Unprocessed Items and Unprocessed Keys

Answer 11

Unprocessed Items are items in a batch write item that failed to write. Unprocessed Keys are keys that failed to read during a BatchGetItem.

Question 12

What is the difference between a Condition Expression and a Filter Expression

Answer 12

Condition Expressions are used in relation to write operations whereas Filter Expressions are read related

Question 13

How can you utalise a Condition Expression to prevent overwriting an element in DynamoDB?

Answer 13

Use the ‘attiribute_not_exists’ condition expression with the partition key and sort key