Free Practice Questions for Amazon Web Services Data-Engineer-Associate Exam

AWS Lake Formation is a service that allows you to easily set up, secure, and manage data lakes. One of the features of Lake Formation is row-level security, which enables you to control access to specific rows or columns of data based on the identity or role of the user. This feature is useful for scenarios where you need to restrict access to sensitive or regulated data, such as customer data from different countries. By registering the S3 bucket as a data lake location in Lake Formation, you can use the Lake Formation console or APIs to define and apply row-level security policies to the data in the bucket. You can also use Lake Formation blueprints to automate the ingestion and transformation of data from various sources into the data lake. This solution requires the least operational effort compared to the other options, as it does not involve creating or moving data, or managing multiple tables, views, or roles. References:

AWS Lake Formation

Row-Level Security

AWS Certified Data Engineer - Associate DEA-C01 Complete Study Guide, Chapter 4: Data Lakes and Data Warehouses, Section 4.2: AWS Lake Formation

Option B is the right approach because the requirement is to mask PII in the log destination (the CloudWatch Logs log group). The exam guide explicitly calls out security responsibilities that include “data encryption and masking” and also emphasizes enabling and preparing logs for audit and governance needs. A log-group–level masking mechanism is therefore the most direct control point to prevent sensitive values from being exposed to anyone who can view logs.

Option A (Glue security configuration) is primarily used to apply protections such as encryption settings for Glue jobs and related outputs; it does not inherently solve the problem of masking PII that has already been emitted into application logs. Option C (Macie) is intended to discover and classify sensitive data—most commonly in Amazon S3—and to produce findings; it is not a log-masking control for CloudWatch Logs. The material reinforces Macie as a discovery/classification service for PII rather than a masking mechanism. Option D adds custom code paths in the ETL job and still may miss PII that appears in framework/system logs; it also violates the “least operational effort” spirit compared to applying a centralized log policy.

Therefore, attaching a data protection policy directly to the CloudWatch Logs log group best meets the masking requirement.

In AWS Glue’s SQL implementation (Spark SQL-compatible), the MERGE INTO statement supports conditional actions.

The clause WHEN MATCHED THEN DELETE deletes matching records from the target table (accounts) where the join condition is true.

“A MERGE INTO statement can perform updates, inserts, or deletes based on the match condition between source and target tables.”

– Ace the AWS Certified Data Engineer - Associate Certification - version 2 - apple.pdf

The data engineer needs to ensure that the data in an Amazon EMR cluster is encrypted both at rest and in transit. The data in Amazon S3 is already encrypted using an AWS KMS key. To meet the requirements, the most suitable solution is to create an EMR security configuration that specifies the correct KMS key for at-rest encryption and use the PEM file for in-transit encryption.

Option C: Create an Amazon EMR security configuration. Specify the appropriate AWS KMS key for at-rest encryption for the S3 bucket. Specify the Amazon S3 path of the PEM file for in-transit encryption. Use the security configuration during EMR cluster creation.This option configures encryption for both data at rest (using KMS keys) and data in transit (using the PEM file for SSL/TLS encryption). This approach ensures that data is fully protected during storage and transfer.

Options A, B, and D either involve creating unnecessary additional security configurations or make inaccurate assumptions about the way encryption configurations are attached.

For exactly-once delivery and processing in Amazon Kinesis Data Streams, the best approach is to design the application so that it handles idempotency. By embedding a unique ID in each record, the application can identify and remove duplicate records during processing.

Exactly-Once Processing:

Kinesis Data Streams does not natively support exactly-once processing. Therefore, idempotency should be designed into the application, ensuring that each record has a unique identifier so that the same event is processed only once, even if it is ingested multiple times.

This pattern is widely used for achieving exactly-once semantics in distributed systems.

The best solution to ensure that the AWS Glue Data Catalog synchronizes with the S3 storage when the company adds new partitions to the bucket with the least latency is to use code that writes data to Amazon S3 to invoke the Boto3 AWS Glue create partition API call. This way, the Data Catalog is updated as soon as new data is written to S3, and the partition information is immediately available for querying by other services. The Boto3 AWS Glue create partition API call allows you to create a new partition in the Data Catalog by specifying the table name, the database name, and the partition values1. You can use this API call in your code that writes data to S3, such as a Python script or an AWS Glue ETL job, to create a partition for each new S3 object key that matches the partitioning scheme.

Option A is not the best solution, as scheduling an AWS Glue crawler to run every morning would introduce a significant latency between the time new data is written to S3 and the time the Data Catalog is updated. AWS Glue crawlers are processes that connect to a data store, progress through a prioritized list of classifiers to determine the schema for your data, and then create metadata tables in the Data Catalog2. Crawlers can be scheduled to run periodically, such as daily or hourly, but they cannot run continuously or in real-time. Therefore, using a crawler to synchronize the Data Catalog with the S3 storage would not meet the requirement of the least latency.

Option B is not the best solution, as manually running the AWS Glue CreatePartition API twice each day would also introduce a significant latency between the time new data is written to S3 and the time the Data Catalog is updated. Moreover, manually running the API would require more operational overhead and human intervention than using code that writes data to S3 to invoke the API automatically.

Option D is not the best solution, as running the MSCK REPAIR TABLE command from the AWS Glue console would also introduce a significant latency between the time new data is written to S3 and the time the Data Catalog is updated. The MSCK REPAIR TABLE command is a SQL command that you can run in the AWS Glue console to add partitions to the Data Catalog based on the S3 object keys that match the partitioning scheme3. However, this command is not meant to be run frequently or in real-time, as it can take a long time to scan the entire S3 bucket and add the partitions. Therefore, using this command to synchronize the Data Catalog with the S3 storage would not meet the requirement of the least latency. References:

AWS Glue CreatePartition API

Populating the AWS Glue Data Catalog

MSCK REPAIR TABLE Command

AWS Certified Data Engineer - Associate DEA-C01 Complete Study Guide

Option C is correct because the requirement is to verify that at least 90% of values in the Email column are valid email addresses. In AWS Glue Data Quality, rules are written in DQDL, and ColumnValues is the rule component used to validate whether column values satisfy a condition or pattern. AWS Glue Data Quality documentation explains that DQDL is the language used to define rules, and it specifically notes that ColumnValues rules can evaluate column content and that NULL values do not pass during comparisons. That is important here because the problem explicitly says the column contains null entries and invalid email values. A threshold of > 0.9 means the rule passes only when more than 90% of rows satisfy the email-validation condition.

Option A is incorrect because Uniqueness checks the percentage of values that are unique, not whether values are valid email addresses. AWS documents Uniqueness as measuring how many values occur exactly once, which is unrelated to email-format validity. Option D has the same issue because UniqueValueRatio addresses uniqueness characteristics, not format validation. Option B uses the right rule family but the wrong threshold because > 0.1 would require only 10% valid values. Therefore, ColumnValues with a threshold greater than 0.9 is the correct choice.

AWS Glue Detect PII transform is designed to identify sensitive data using custom pattern matching, making it well suited for detecting PII in proprietary or non-standard data formats. The transform integrates directly into AWS Glue ETL jobs and requires minimal configuration beyond defining the detection patterns.

Amazon Macie primarily relies on managed data identifiers and machine learning models optimized for common data formats such as JSON, CSV, and text. While Macie supports custom identifiers, it is less efficient for deeply proprietary formats and introduces additional service configuration.

Using AWS Lambda with custom regular expressions or Amazon Athena with SQL-based pattern matching would require building, operating, and maintaining custom logic across multiple buckets, increasing operational overhead and complexity.

AWS Glue provides a serverless, scalable, and centralized approach for PII detection as part of an existing data processing pipeline, making it the most operationally efficient solution for this requirement.

Therefore, Option A is the best answer.

Amazon Kinesis Data Firehose is a fully managed data ingestion service that enables reliable and scalable delivery of streaming and batch data into Amazon S3 with minimal operational overhead. This directly satisfies the requirement for a fully managed AWS ingestion service while avoiding the need to provision, scale, or manage infrastructure.

By using the Amazon Kinesis Agent on the on-premises servers, the company can automatically forward daily data files to Kinesis Data Firehose. Firehose handles buffering, retry logic, scaling, and delivery without requiring administrative effort. Delivering the data to Amazon S3 allows seamless integration with Amazon Athena, which natively queries data stored in S3 without requiring data movement or transformation.

Enabling Amazon S3 versioning protects files from accidental deletion by preserving previous versions of objects. This aligns with AWS best practices for data durability and governance, especially for analytics workloads and compliance requirements.

Other options introduce unnecessary operational complexity. AWS DataSync with Amazon EFS is not optimized for Athena-based analytics. AWS Glue jobs and Amazon RDS are unsuitable for file-based analytical access. A self-managed Apache Kafka solution with Amazon MSK significantly increases operational overhead.

Therefore, option B is the most efficient, scalable, and operationally optimal solution according to AWS Certified Data Engineer – Associate best practices.

Amazon Redshift query performance for large joins depends heavily on data distribution and query optimization. Using the KEY distribution style on both tables ensures that rows with the same join key are co-located on the same compute nodes, minimizing costly data redistribution during joins.

Selecting a high-cardinality column as the distribution key is critical to evenly distribute data across nodes and prevent data skew. Low-cardinality keys can cause hotspots where too much data resides on a small number of nodes, degrading performance.

Using EVEN distribution on the 10-billion-row table and ALL distribution on the 900-million-row table is inefficient because ALL distribution replicates the entire table to every node, which is not appropriate for large datasets. The Amazon Redshift query optimizer operates automatically and does not require manual selection.

Amazon Redshift Advisor analyzes workload patterns and provides actionable recommendations for distribution styles, sort keys, and query optimizations. Using Redshift Advisor allows the data engineer to apply proven optimizations based on actual cluster usage.

Therefore, combining KEY distribution with a high-cardinality join column and leveraging Amazon Redshift Advisor recommendations is the most effective solution to improve query performance.