On-demand vs provisioned cost comparison in DynamoDB - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the billing mode as on-demand in the table creation.

DynamoDB

aws dynamodb create-table --table-name Music --attribute-definitions AttributeName=Artist,AttributeType=S --key-schema AttributeName=Artist,KeyType=HASH --billing-mode [1]

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

AON_DEMAND

BPAY_PER_REQUEST

CPROVISIONED

DSTANDARD

Attempts:

3 left

💡 Hint

Common Mistakes

Using PROVISIONED instead of PAY_PER_REQUEST for on-demand billing mode.

Using ON_DEMAND which is not the correct billing mode string.

The billing mode for on-demand capacity in DynamoDB is specified as PAY_PER_REQUEST.

2fill in blank

medium

Complete the code to set the read capacity units for provisioned mode.

DynamoDB

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

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

A5

B20

C0

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Setting read capacity units to 0 which disables reads.

Setting read capacity units too high without need.

Setting ReadCapacityUnits to 5 matches the write capacity units and is a common balanced setting.

3fill in blank

hard

Fix the error in the cost calculation formula for provisioned mode.

DynamoDB

cost = (read_units * 0.00013 + write_units * 0.00065) * [1]

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Ahours_per_month

Bdays_per_month

Cminutes_per_month

Dseconds_per_month

Attempts:

3 left

💡 Hint

Common Mistakes

Using days or minutes instead of hours in the formula.

Forgetting to multiply by time period.

The cost is calculated per hour, so multiply by the number of hours in a month.

4fill in blank

hard

Fill both blanks to complete the on-demand cost calculation formula.

DynamoDB

cost = (read_requests * [1] + write_requests * [2]) / 1000000

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

A0.25

B1.25

C0.00025

D0.00125

Attempts:

3 left

💡 Hint

Common Mistakes

Using per-request costs like 0.00025 instead of per-million costs.

Mixing up read and write request costs.

On-demand read request units cost $0.25 per million and write request units cost $1.25 per million.

5fill in blank

hard

Fill all three blanks to complete the provisioned throughput cost formula with monthly hours.

DynamoDB

cost = (read_units * [1] + write_units * [2]) * [3]

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

A0.00013

B0.00065

C720

D730

Attempts:

3 left

💡 Hint

Common Mistakes

Using 720 hours instead of 730 hours for monthly calculation.

Swapping read and write unit costs.

Read units cost $0.00013/hr, write units $0.00065/hr, multiplied by 730 hours in a month.