Cost estimation for access patterns in DynamoDB - Mini Project: Build & Apply

Cost Estimation for Access Patterns in DynamoDB

📖 Scenario: You are managing a DynamoDB table for an online bookstore. You want to estimate the cost of different access patterns based on read and write operations.

🎯 Goal: Build a simple DynamoDB cost estimation model that calculates the total read and write capacity units (RCUs and WCUs) needed for given access patterns.

📋 What You'll Learn

Create a dictionary with exact read and write counts for different operations

Add a configuration variable for the cost per capacity unit

Calculate total RCUs and WCUs using the given counts

Calculate the total estimated cost based on capacity units and cost per unit

💡 Why This Matters

🌍 Real World

Estimating costs helps businesses plan budgets and optimize their DynamoDB usage to avoid surprises in billing.

💼 Career

Understanding cost estimation is important for cloud engineers, database administrators, and developers working with AWS DynamoDB.

1

Setup Access Pattern Counts

Create a dictionary called access_counts with these exact entries: 'reads': 1500, 'writes': 300.

DynamoDB

# Create the access_counts dictionary with reads and writes
# Your code here

Need a hint?

Use curly braces to create a dictionary with keys 'reads' and 'writes' and their respective values.

2

Add Cost Per Capacity Unit Configuration

Create two variables: cost_per_rcu set to 0.00013 and cost_per_wcu set to 0.00065.

DynamoDB

access_counts = {'reads': 1500, 'writes': 300}
# Define cost_per_rcu and cost_per_wcu variables
# Your code here

Need a hint?

Assign the exact float values to the variables as shown.

3

Calculate Total Capacity Units

Create two variables: total_rcu assigned from access_counts['reads'] and total_wcu assigned from access_counts['writes'].

DynamoDB

access_counts = {'reads': 1500, 'writes': 300}
cost_per_rcu = 0.00013
cost_per_wcu = 0.00065
# Calculate total_rcu and total_wcu from access_counts
# Your code here

Need a hint?

Use dictionary key access to assign values to total_rcu and total_wcu.

4

Calculate Total Estimated Cost

Create a variable total_cost that calculates the sum of total_rcu * cost_per_rcu and total_wcu * cost_per_wcu.

DynamoDB

access_counts = {'reads': 1500, 'writes': 300}
cost_per_rcu = 0.00013
cost_per_wcu = 0.00065
total_rcu = access_counts['reads']
total_wcu = access_counts['writes']
# Calculate total_cost based on capacity units and cost per unit
# Your code here

Need a hint?

Multiply the counts by their costs and add them to get total_cost.