Table capacity modes (on-demand vs provisioned) in DynamoDB - Hands-On Comparison

DynamoDB Table Capacity Modes: On-Demand vs Provisioned

📖 Scenario: You are building a simple inventory system for a small online store. You want to create a DynamoDB table to store product information. You need to decide how to set the table's capacity mode to handle read and write traffic efficiently.

🎯 Goal: Create a DynamoDB table named Products with a primary key ProductID. First, set up the table with the Provisioned capacity mode and specify read and write capacity units. Then, change the capacity mode to On-Demand to allow automatic scaling without specifying capacity units.

📋 What You'll Learn

Create a DynamoDB table named Products with ProductID as the partition key.

Set the table's capacity mode to Provisioned with ReadCapacityUnits set to 5 and WriteCapacityUnits set to 5.

Add a configuration variable to switch the capacity mode to On-Demand.

Update the table creation code to use the On-Demand capacity mode when the configuration variable is set.

💡 Why This Matters

🌍 Real World

Choosing the right capacity mode in DynamoDB helps manage costs and performance for applications with varying traffic patterns.

💼 Career

Understanding DynamoDB capacity modes is essential for cloud developers and database administrators working with AWS to optimize database scalability and cost.

1

Create DynamoDB table with Provisioned capacity mode

Write the AWS CLI command to create a DynamoDB table named Products with ProductID as the partition key. Set the capacity mode to Provisioned with ReadCapacityUnits and WriteCapacityUnits both set to 5.

DynamoDB

# Your AWS CLI command here to create the table with provisioned capacity

Need a hint?

Use aws dynamodb create-table with --provisioned-throughput to set capacity units.

2

Add configuration variable for capacity mode

Create a shell variable named CAPACITY_MODE and set it to PROVISIONED to represent the current capacity mode setting.

DynamoDB

aws dynamodb create-table \
    --table-name Products \
    --attribute-definitions AttributeName=ProductID,AttributeType=S \
    --key-schema AttributeName=ProductID,KeyType=HASH \
    --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

# Define capacity mode variable
# Your code here

Need a hint?

Use CAPACITY_MODE=PROVISIONED to set the variable.

3

Write conditional logic to choose capacity mode

Write a shell if statement that checks if CAPACITY_MODE equals PROVISIONED. If yes, set a variable CAPACITY_PARAMS to --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5. Otherwise, set CAPACITY_PARAMS to --billing-mode PAY_PER_REQUEST for on-demand mode.

DynamoDB

aws dynamodb create-table \
    --table-name Products \
    --attribute-definitions AttributeName=ProductID,AttributeType=S \
    --key-schema AttributeName=ProductID,KeyType=HASH \
    --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5

CAPACITY_MODE=PROVISIONED

# Add if statement to set CAPACITY_PARAMS based on CAPACITY_MODE
# Your code here

Need a hint?

Use if [ "$CAPACITY_MODE" = "PROVISIONED" ] to check the variable.

4

Create table using dynamic capacity mode parameter

Rewrite the AWS CLI command to create the Products table using the variable CAPACITY_PARAMS for capacity settings instead of hardcoding. This will allow switching between provisioned and on-demand modes by changing CAPACITY_MODE.

DynamoDB

aws dynamodb create-table \
    --table-name Products \
    --attribute-definitions AttributeName=ProductID,AttributeType=S \
    --key-schema AttributeName=ProductID,KeyType=HASH \
    $CAPACITY_PARAMS

CAPACITY_MODE=PROVISIONED

if [ "$CAPACITY_MODE" = "PROVISIONED" ]; then
    CAPACITY_PARAMS="--provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5"
else
    CAPACITY_PARAMS="--billing-mode PAY_PER_REQUEST"
fi

# Use $CAPACITY_PARAMS in the create-table command
# Your code here

Need a hint?

Use $CAPACITY_PARAMS in the create-table command to apply the selected capacity mode.