Free Amazon Web Services Data-Engineer-Associate Practice Exam with Questions & Answers | Set: 6

Problem Analysis:

Millions of 1 KB JSON files in S3 are being processed and converted to Apache Parquet format using AWS Glue.

Processing time is increasing due to the additional testing facilities.

The goal is to reduce processing time while using the existing AWS Glue framework.

Key Considerations:

AWS Glue offers the dynamic frame file-grouping feature, which consolidates small files into larger, more efficient datasets during processing.

Grouping smaller files reduces overhead and speeds up processing.

Solution Analysis:

Option A: Lambda for File Grouping

Using Lambda to group files would add complexity and operational overhead. Glue already offers built-in grouping functionality.

Option B: AWS Glue Dynamic Frame File-Grouping

This option directly addresses the issue by grouping small files during Glue job execution.

Minimizes data processing time with no extra overhead.

Option C: Redshift COPY Command

COPY directly loads raw files but is not designed for pre-processing (conversion to Parquet).

Option D: Amazon EMR

While EMR is powerful, replacing Glue with EMR increases operational complexity.

Final Recommendation:

Use AWS Glue dynamic frame file-grouping for optimized data ingestion and processing.

AWS Glue Dynamic Frames

Optimizing Glue Performance

Amazon Redshift data sharing now supports bi-directional and selective write access through datashare namespaces.

This allows centralized management of permissions from headquarters while giving Regional clusters controlled write access to specific datasets — adhering to least privilege and minimizing admin overhead.

“Use Redshift datashares with write permissions and namespaces to enable controlled cross-Region data collaboration while maintaining centralized governance.”

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

This configuration ensures near real-time inventory updates, centralized access management, and compliance with AWS security best practices.

The AWS Glue Data Catalog is an Apache Hive metastore-compatible catalog that provides a central metadata repository for various data sources and formats. You can use the AWS Glue Data Catalog as an external Hive metastore for Amazon EMR and Amazon Athena queries, and import metadata from existing Hive metastores into the Data Catalog. This solution requires the least development effort, as you can use AWS Glue crawlers to automatically discover and catalog the metadata from Hive, and use the AWS Glue console, AWS CLI, or Amazon EMR API to configure the Data Catalog as the Hive metastore. The other options are either more complex or require additional steps, such as setting up Apache Ranger for security, managing a Hive metastore on an EMR cluster or an RDS instance, or migrating the metadata manually. References:

Using the AWS Glue Data Catalog as the metastore for Hive (Section: Specifying AWS Glue Data Catalog as the metastore)

Metadata Management: Hive Metastore vs AWS Glue (Section: AWS Glue Data Catalog)

AWS Glue Data Catalog support for Spark SQL jobs (Section: Importing metadata from an existing Hive metastore)

AWS Certified Data Engineer - Associate DEA-C01 Complete Study Guide (Chapter 5, page 131)

AWS Glue DataBrew is a visual data preparation tool that allows you to clean, normalize, and transform data without writing code. You can use DataBrew to create recipes that define the steps to apply to your data, such as filtering, renaming, splitting, or aggregating columns. You can also use DataBrew to run jobs that execute the recipes on your data sources, such as Amazon S3, Amazon Redshift, or Amazon Aurora. DataBrew integrates with AWS Glue Data Catalog, which is a centralized metadata repository for your data assets1.

The solution that meets the requirement with the least operational effort is to use AWS Glue DataBrew to create a recipe that uses the COUNT_DISTINCT aggregate function to calculate the number of distinct customers. This solution has the following advantages:

It does not require you to write any code, as DataBrew provides a graphical user interface that lets you explore, transform, and visualize your data. You can use DataBrew to concatenate the columns that contain customer first names and last names, and then use the COUNT_DISTINCT aggregate function to count the number of unique values in the resulting column2.

It does not require you to provision, manage, or scale any servers, clusters, or notebooks, as DataBrew is a fully managed service that handles all the infrastructure for you. DataBrew can automatically scale up or down the compute resources based on the size and complexity of your data and recipes1.

It does not require you to create or update any AWS Glue Data Catalog entries, as DataBrew can automatically create and register the data sources and targets in the Data Catalog. DataBrew can also use the existing Data Catalog entries to access the data in S3 or other sources3.

Option A is incorrect because it suggests creating and running an Apache Spark job in an AWS Glue notebook. This solution has the following disadvantages:

It requires you to write code, as AWS Glue notebooks are interactive development environments that allow you to write, test, and debug Apache Spark code using Python or Scala. You need to use the Spark SQL or the Spark DataFrame API to read the S3 file and calculate the number of distinct customers.

It requires you to provision and manage a development endpoint, which is a serverless Apache Spark environment that you can connect to your notebook. You need to specify the type and number of workers for your development endpoint, and monitor its status and metrics.

It requires you to create or update the AWS Glue Data Catalog entries for the S3 file, either manually or using a crawler. You need to use the Data Catalog as a metadata store for your Spark job, and specify the database and table names in your code.

Option B is incorrect because it suggests creating an AWS Glue crawler to create an AWS Glue Data Catalog of the S3 file, and running SQL queries from Amazon Athena to calculate the number of distinct customers. This solution has the following disadvantages:

It requires you to create and run a crawler, which is a program that connects to your data store, progresses through a prioritized list of classifiers to determine the schema for your data, and then creates metadata tables in the Data Catalog. You need to specify the data store, the IAM role, the schedule, and the output database for your crawler.

It requires you to write SQL queries, as Amazon Athena is a serverless interactive query service that allows you to analyze data in S3 using standard SQL. You need to use Athena to concatenate the columns that contain customer first names and last names, and then use the COUNT(DISTINCT) aggregate function to count the number of unique values in the resulting column.

Option C is incorrect because it suggests creating and running an Apache Spark job in Amazon EMR Serverless to calculate the number of distinct customers. This solution has the following disadvantages:

It requires you to write code, as Amazon EMR Serverless is a service that allows you to run Apache Spark jobs on AWS without provisioning or managing any infrastructure. You need to use the Spark SQL or the Spark DataFrame API to read the S3 file and calculate the number of distinct customers.

It requires you to create and manage an Amazon EMR Serverless cluster, which is a fully managed and scalable Spark environment that runs on AWS Fargate. You need to specify the cluster name, the IAM role, the VPC, and the subnet for your cluster, and monitor its status and metrics.

It requires you to create or update the AWS Glue Data Catalog entries for the S3 file, either manually or using a crawler. You need to use the Data Catalog as a metadata store for your Spark job, and specify the database and table names in your code.

1: AWS Glue DataBrew - Features

2: Working with recipes - AWS Glue DataBrew

3: Working with data sources and data targets - AWS Glue DataBrew

[4]: AWS Glue notebooks - AWS Glue

[5]: Development endpoints - AWS Glue

[6]: Populating the AWS Glue Data Catalog - AWS Glue

[7]: Crawlers - AWS Glue

[8]: Amazon Athena - Features

[9]: Amazon EMR Serverless - Features

[10]: Creating an Amazon EMR Serverless cluster - Amazon EMR

[11]: Using the AWS Glue Data Catalog with Amazon EMR Serverless - Amazon EMR

Problem Analysis:

The company needs cross-account access to allow QuickSight in BI-Account to interact with an S3 bucket in Hub-Account.

The bucket is encrypted with an AWS KMS key.

Appropriate permissions must be set for both S3 access and KMS decryption.

Key Considerations:

QuickSight requires IAM permissions to access S3 data and decrypt files using the KMS key.

Both S3 and KMS permissions need to be properly configured across accounts.

Solution Analysis:

Option A: Use Existing KMS Key for Encryption

While the existing KMS key is used for encryption, it must also grant decryption permissions to QuickSight.

Option B: Add S3 Bucket to QuickSight Role

Granting S3 bucket access to the QuickSight service role is necessary for cross-account access.

Option C: AWS RAM for Bucket Sharing

AWS RAM is not required; bucket policies and IAM roles suffice for granting cross-account access.

Option D: IAM Policy for KMS Access

QuickSight’s service role in BI-Account needs explicit permissions to use the KMS key for decryption.

Option E: Add KMS Key as Resource for Role

The KMS key must explicitly list the QuickSight role as an entity that can access it.

Implementation Steps:

S3 Bucket Policy in Hub-Account:Add a policy to the S3 bucket granting the QuickSight service role access:

json

{

" Version " : " 2012-10-17 " ,

" Statement " : [

{

" Effect " : " Allow " ,

" Principal " : { " AWS " : " arn:aws:iam:: < BI-Account-ID > :role/service-role/QuickSightRole " },

" Action " : " s3:GetObject " ,

" Resource " : " arn:aws:s3::: < Bucket-Name > /* "

}

]

}

KMS Key Policy in Hub-Account:Add permissions for the QuickSight role:

{

" Version " : " 2012-10-17 " ,

" Statement " : [

{

" Effect " : " Allow " ,

" Principal " : { " AWS " : " arn:aws:iam:: < BI-Account-ID > :role/service-role/QuickSightRole " },

" Action " : [

" kms:Decrypt " ,

" kms:DescribeKey "

],

" Resource " : " * "

}

]

}

IAM Policy for QuickSight Role in BI-Account:Attach the following policy to the QuickSight service role:

{

" Version " : " 2012-10-17 " ,

" Statement " : [

{

" Effect " : " Allow " ,

" Action " : [

" s3:GetObject " ,

" kms:Decrypt "

],

" Resource " : [

" arn:aws:s3::: < Bucket-Name > /* " ,

" arn:aws:kms: < region > : < Hub-Account-ID > :key/ < KMS-Key-ID > "

]

}

]

}

Setting Up Cross-Account S3 Access

AWS KMS Key Policy Examples

Amazon QuickSight Cross-Account Access

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 query editor v2 in Amazon Redshift is a web-based tool that allows users to run SQL queries and scripts on Amazon Redshift clusters. The query editor v2 supports creating and managing materialized views, which are precomputed results of a query that can improve the performance of subsequent queries. The query editor v2 also supports scheduling queries to run at specified intervals, which can be used to refresh materialized views automatically. This solution requires the least effort, as it does not involve any additional services, coding, or configuration. The other solutions are more complex and require more operational overhead. Apache Airflow is an open-source platform for orchestrating workflows, which can be used to refresh materialized views, but it requires setting up and managing an Airflow environment, creating DAGs (directed acyclic graphs) to define the workflows, and integrating with Amazon Redshift. AWS Lambda is a serverless compute service that can run code in response to events, which can be used to refresh materialized views, but it requires creating and deploying Lambda functions, defining UDFs within Amazon Redshift, and triggering the functions using events or schedules. AWS Glue is a fully managed ETL service that can run jobs to transform and load data, which can be used to refresh materialized views, but it requires creating and configuring Glue jobs, defining Glue workflows to orchestrate the jobs, and scheduling the workflows using triggers. References:

Query editor V2

Working with materialized views

Scheduling queries

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

Amazon DynamoDB is a serverless, low-latency, NoSQL database ideal for semi-structured data.

Adding DynamoDB Accelerator (DAX) provides microsecond response times for read-heavy workloads.

“For applications requiring millisecond or sub-millisecond reads with serverless operation, use DynamoDB with DAX caching.”

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

Apache Iceberg query performance depends heavily on metadata optimization and file layout efficiency. Generating column-level statistics allows query engines such as AWS Glue, Amazon Athena, and Amazon Redshift to perform predicate pushdown and data skipping. These statistics help avoid scanning unnecessary Parquet files and significantly reduce query execution time.

Real-time streaming workloads often generate many small files, which degrades query performance. Table compaction consolidates small Parquet files into fewer, larger files, improving scan efficiency and reducing metadata overhead. Iceberg supports compaction as a core optimization technique, and Glue can schedule these operations automatically.

Iceberg does not use traditional indexes, so index optimization is not applicable. Copy-on-write affects write semantics and consistency, not query speed. Views do not improve physical query performance.

Therefore, generating statistics and compacting files are the two most effective optimizations.