Amazon Web Services Updated SAA-C03 Exam Questions and Answers by alaia

AWS Lambda is event driven and “scales automatically with the number of requests,” charging per request and compute duration in milliseconds; you can schedule with Amazon EventBridge rules. Allocating 1 GB memory proportionally increases available CPU, which suits short CPU bursts. For a 10-second, once-per-hour job, Lambda eliminates instance idle time, providing the lowest cost and no servers to manage. Fargate tasks (A) bill per-second with a 1-minute minimum and require container packaging; for a 10-second job, costs are higher than Lambda. Options C and D keep EC2 management overhead and either maintain instances or add start/stop orchestration complexity; EC2 costs dominate because the instance sits idle for 59+ minutes each hour. Therefore, Lambda + EventBridge is the most cost-effective and operationally simple solution.

Amazon Athenais a serverless query service that allows you to run SQL queries directly on data stored in Amazon S3 without the need for a data warehouse. It is cost-effective because you only pay for the queries you run, and it can handleApache Parquetfiles efficiently. Additionally, Athena integrates with KMS, making it suitable for querying encrypted data.

Key AWS features:

Cost-Effective: Athena charges only for the data scanned by the queries, making it a more cost-effective solution compared to Redshift or EMR for occasional queries.

Direct S3 Querying: Athena supports querying data directly in S3, including Parquet files, without needing to move the data.

AWS Documentation: Athena ' s compatibility with encrypted Parquet files in S3 makes it the ideal choice for this scenario, reducing both cost and complexity​​.

The most resilient and scalable architecture for handling millions of high-resolution images with frequent updates is to store the binary images in Amazon S3 and store their metadata or reference (geographic code and S3 URL) in Amazon DynamoDB.

From AWS Documentation:

“Store large objects like images in Amazon S3 and use Amazon DynamoDB to store metadata and references. This design pattern is scalable, highly available, and cost-effective.”

(Source: AWS Architecture Blog – Best Practices for Handling Large Objects)

Why B is correct:

Amazon S3 is designed for storing large volumes of binary data (images).

DynamoDB provides low-latency reads/writes using the geographic code as the partition key.

Highly available, serverless, and auto-scaling, suitable for disaster scenarios with bursts of activity.

Reduces pressure on the database layer by separating metadata from image storage.

Why the others are incorrect:

Option A and D: Storing images directly in RDS is expensive, unscalable, and not optimal for binary storage.

Option C: DynamoDB is suitable, but storing actual binary image data in DynamoDB is not best practice due to item size limits (400 KB) and performance concerns.

Amazon Kinesis Data Streams provides a highly scalable and durable service for ingesting real-time streaming data. By decoupling ingestion and processing, Kinesis can handle large spikes in traffic without service disruption. Lambda functions (or other consumers) can then process the data as it arrives, scaling automatically. This pattern avoids 503 errors due to compute saturation and delivers a resilient, serverless, and highly scalable architecture.

Reference Extract from AWS Documentation / Study Guide:

" Kinesis Data Streams provides a scalable and durable real-time data streaming service. Coupling Kinesis with AWS Lambda enables event-driven processing, elasticity, and decoupling between ingestion and processing layers. "

Source: AWS Certified Solutions Architect – Official Study Guide, Streaming and Serverless section.