Table capacity modes (on-demand vs provisioned) in DynamoDB - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the table capacity mode to on-demand.

DynamoDB

aws dynamodb create-table --table-name MyTable --billing-mode [1]

Drag options to blanks, or click blank then click option'

APAY_PER_REQUEST

BON_DEMAND

CPROVISIONED

DSTANDARD

Attempts:

3 left

💡 Hint

Common Mistakes

Using PROVISIONED instead of PAY_PER_REQUEST for on-demand mode.

Using ON_DEMAND which is not a valid billing mode value.

The correct billing mode value for on-demand capacity is PAY_PER_REQUEST.

2fill in blank

medium

Complete the code to update an existing table to provisioned capacity mode.

DynamoDB

aws dynamodb update-table --table-name MyTable --billing-mode [1] --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

Drag options to blanks, or click blank then click option'

APAY_PER_REQUEST

BSTANDARD

CON_DEMAND

DPROVISIONED

Attempts:

3 left

💡 Hint

Common Mistakes

Using PAY_PER_REQUEST when trying to set provisioned mode.

Omitting provisioned throughput parameters.

To switch to provisioned capacity, use PROVISIONED as the billing mode.

3fill in blank

hard

Fix the error in the command to create a table with provisioned capacity.

DynamoDB

aws dynamodb create-table --table-name MyTable --billing-mode [1] --provisioned-throughput ReadCapacityUnits=10,WriteCapacityUnits=10

Drag options to blanks, or click blank then click option'

APAY_PER_REQUEST

BON_DEMAND

CPROVISIONED

DSTANDARD

Attempts:

3 left

💡 Hint

Common Mistakes

Using PAY_PER_REQUEST with provisioned throughput parameters.

Using ON_DEMAND which is invalid in this context.

The billing mode for provisioned capacity is PROVISIONED. Using PAY_PER_REQUEST or ON_DEMAND here causes errors.

4fill in blank

hard

Fill both blanks to create a table with on-demand capacity and a primary key named 'UserId'.

DynamoDB

aws dynamodb create-table --table-name Users --attribute-definitions AttributeName=UserId,AttributeType=[1] --key-schema AttributeName=UserId,KeyType=[2] --billing-mode PAY_PER_REQUEST

Drag options to blanks, or click blank then click option'

AS

BHASH

CN

DRANGE

Attempts:

3 left

💡 Hint

Common Mistakes

Using RANGE instead of HASH for the primary key.

Using N when the key is a string.

The primary key attribute type is S for string, and the key type is HASH for partition key.

5fill in blank

hard

Fill all three blanks to update a table to provisioned mode with 8 read and 4 write capacity units.

DynamoDB

aws dynamodb update-table --table-name Orders --billing-mode [1] --provisioned-throughput ReadCapacityUnits=[2],WriteCapacityUnits=[3]

Drag options to blanks, or click blank then click option'

APAY_PER_REQUEST

BPROVISIONED

C4

D8

Attempts:

3 left

💡 Hint

Common Mistakes

Using PAY_PER_REQUEST when specifying provisioned throughput.

Swapping read and write capacity values.

Use PROVISIONED for billing mode, with 8 read and 4 write capacity units.

Practice

1. Which DynamoDB table capacity mode automatically adjusts to your application's traffic without requiring manual capacity settings?

easy

A. On-demand mode

B. Provisioned mode

C. Reserved mode

D. Manual mode

Solution

1. Step 1: Understand capacity modes in DynamoDB

   DynamoDB offers two main capacity modes: on-demand and provisioned. On-demand mode automatically adjusts capacity based on traffic.

2. Step 2: Identify the mode that adjusts automatically

   On-demand mode charges per request and scales automatically without manual settings, unlike provisioned mode which requires fixed capacity.

3. Final Answer:

   On-demand mode -> Option A

4. Quick Check:

   Automatic scaling = On-demand mode [OK]

Hint: Automatic scaling means on-demand mode [OK]

Common Mistakes:

• Confusing provisioned mode as automatic
• Thinking reserved or manual modes exist
• Assuming manual capacity adjustment is automatic

2. Which of the following is the correct way to specify provisioned capacity when creating a DynamoDB table using AWS CLI?

easy

A. --billing-mode PAY_PER_REQUEST

B. --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

C. --capacity-mode ON_DEMAND

D. --read-write-capacity 10

Solution

1. Step 1: Recall AWS CLI syntax for provisioned capacity

   Provisioned mode requires specifying read and write capacity units using --provisioned-throughput with ReadCapacityUnits and WriteCapacityUnits.

2. Step 2: Match correct syntax option

   --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 uses the correct syntax. The --billing-mode PAY_PER_REQUEST and --capacity-mode ON_DEMAND options specify on-demand mode, while --read-write-capacity is invalid.

3. Final Answer:

   --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 -> Option B

4. Quick Check:

   Provisioned throughput syntax = --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5 [OK]

Hint: Provisioned mode uses --provisioned-throughput flag [OK]

Common Mistakes:

• Using PAY_PER_REQUEST flag for provisioned mode
• Confusing capacity mode flags
• Using invalid flags like --read-write-capacity

3. Consider a DynamoDB table in provisioned mode with ReadCapacityUnits=5 and WriteCapacityUnits=5. If your application suddenly sends 20 read requests per second, what will happen?

medium

A. All 20 read requests succeed without delay

B. The table switches to on-demand mode automatically

C. Some read requests may be throttled due to exceeding capacity

D. DynamoDB automatically increases capacity to handle 20 requests

Solution

1. Step 1: Understand provisioned capacity limits

   Provisioned mode sets fixed read/write capacity units. Here, 5 read units allow about 5 strongly consistent reads per second.

2. Step 2: Analyze traffic exceeding capacity

   Sending 20 read requests exceeds the provisioned 5 units. DynamoDB throttles excess requests instead of automatically scaling or switching modes.

3. Final Answer:

   Some read requests may be throttled due to exceeding capacity -> Option C

4. Quick Check:

   Exceeding provisioned units causes throttling [OK]

Hint: Provisioned mode throttles if requests exceed capacity [OK]

Common Mistakes:

• Assuming automatic scaling in provisioned mode
• Thinking all requests always succeed
• Believing table switches modes automatically

4. You created a DynamoDB table with the following command:

aws dynamodb create-table --table-name MyTable --billing-mode PROVISIONED

But you forgot to specify provisioned throughput. What will happen?

medium

A. Table is created with default capacity of 5 read and 5 write units

B. Table is created but capacity is unlimited

C. Table is created in on-demand mode automatically

D. Table creation fails with an error about missing provisioned throughput

Solution

1. Step 1: Check requirements for provisioned mode

   Provisioned mode requires specifying ReadCapacityUnits and WriteCapacityUnits explicitly during table creation.

2. Step 2: Understand AWS CLI behavior on missing parameters

   Omitting provisioned throughput causes AWS CLI to return an error because required parameters are missing.

3. Final Answer:

   Table creation fails with an error about missing provisioned throughput -> Option D

4. Quick Check:

   Missing provisioned throughput causes creation error [OK]

Hint: Provisioned mode needs capacity units specified [OK]

Common Mistakes:

• Assuming default capacity is assigned
• Thinking table switches to on-demand mode
• Believing capacity is unlimited without settings

5. A startup expects unpredictable traffic spikes but wants to control costs during low usage. Which DynamoDB capacity mode strategy is best to balance cost and performance?

hard

A. Use on-demand mode to automatically handle spikes and pay per request

B. Use provisioned mode with low capacity and manually increase during spikes

C. Use provisioned mode with high capacity to handle spikes

D. Switch between on-demand and provisioned modes daily

Solution

1. Step 1: Analyze startup traffic pattern

   Unpredictable spikes mean traffic varies a lot, so automatic scaling is important to avoid throttling or overpaying.

2. Step 2: Evaluate capacity mode options for cost and performance

   On-demand mode charges per request and scales automatically, ideal for unpredictable traffic and cost control. Provisioned mode requires manual adjustments and risks throttling or wasted capacity.

3. Final Answer:

   Use on-demand mode to automatically handle spikes and pay per request -> Option A

4. Quick Check:

   Unpredictable traffic = On-demand mode best [OK]

Hint: Unpredictable traffic? Choose on-demand mode [OK]

Common Mistakes:

• Choosing high provisioned capacity wastes money
• Manually adjusting capacity is slow and error-prone
• Switching modes daily is not supported