Practice Exams | AWS Certified Data Engineer - Associate (Udemy.com)

Preparing for AWS Certified Data Engineer Associate DEA-C01? This is THE practice exams course to give you the winning edge.

These practice exams have been co-authored by Stephane Maarek and Abhishek Singh who bring their collective experience of passing 20 AWS Certifications to the table.

Why Serious Learners Choose These Practice Exams

• Human-crafted, exam-aware questions backed by real AWS expertise
  Every item is designed by an instructor with deep, hands-on AWS experience and insight into how AWS actually tests concepts, not mass-generated by generic AI tools.

• Authentic exam feel with blueprint-aligned difficulty and distractors
  Questions mirror the tone, complexity, and trap patterns used in actual certification exams, helping learners build confidence under realistic conditions.

• Enhanced with diagrams, flows, and AWS-doc-based explanations
  Answers include visually rich explanations, custom diagrams, and carefully written descriptions distilled from official AWS documentation.

• Updated to reflect real-world patterns and the latest AWS services
  Content stays aligned with how AWS evolves its exams, focusing on the topics and service combinations most likely to appear in current and upcoming versions.

• Designed to build actual problem-solving skill, not just memorization
  Scenarios train reasoning across architectures, security, data, and data engineering patterns, preparing learners to think like Data Engineers instead of guessing. Do not just ace the exam, become a stronger AWS Professional.

We want you to think of this course as the final pit-stop so that you can cross the winning line with absolute confidence and get AWS Certified! Trust our process, you are in good hands.

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SAMPLE QUESTION:

A data engineer is encountering slow query performance while executing Amazon Athena queries on datasets stored in an Amazon S3 bucket, with AWS Glue Data Catalog serving as the metadata repository. The data engineer has identified the root cause of the sluggish performance as the excessive number of partitions in the S3 bucket, leading to increased Athena query planning times.

What are the two possible approaches to mitigate this issue and enhance query efficiency (Select two)?

1. Transform the data in each partition to Apache ORC format

2. Compress the files in gzip format to improve query performance against the partitions

3. Perform bucketing on the data in each partition

4. Set up an AWS Glue partition index and leverage partition filtering via the GetPartitions call

5. Set up Athena partition projection based on the S3 bucket prefix

What's your guess? Scroll below for the answer.

Correct: 4,5.

Explanation:

Correct options:

Set up an AWS Glue partition index and leverage partition filtering via the GetPartitions call

When you create a partition index, you specify a list of partition keys that already exist on a given table. The partition index is sub list of partition keys defined in the table. A partition index can be created on any permutation of partition keys defined in the table. For the above sales_data table, the possible indexes are (country, category, creationDate), (country, category, year), (country, category), (country), (category, country, year, month), and so on.

Let's take a sales_data table as an example which is partitioned by the keys Country, Category, Year, Month, and creationDate. If you want to obtain sales data for all the items sold for the Books category in the year 2020 after 2020-08-15, you have to make a GetPartitions request with the expression "Category = 'Books' and creationDate > '2020-08-15'" to the Data Catalog.

If no partition indexes are present on the table, AWS Glue loads all the partitions of the table and then filters the loaded partitions using the query expression provided by the user in the GetPartitions request. The query takes more time to run as the number of partitions increases on a table with no indexes. With an index, the GetPartitions query will try to fetch a subset of the partitions instead of loading all the partitions in the table.

Overview of AWS Glue partition index and partition filtering:

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Set up Athena partition projection based on the S3 bucket prefix

Processing partition information can be a bottleneck for Athena queries when you have a very large number of partitions and aren’t using AWS Glue partition indexing. You can use partition projection in Athena to speed up query processing of highly partitioned tables and automate partition management. Partition projection helps minimize this overhead by allowing you to query partitions by calculating partition information rather than retrieving it from a metastore. It eliminates the need to add partitions’ metadata to the AWS Glue table.

In partition projection, partition values, and locations are calculated from configuration rather than read from a repository like the AWS Glue Data Catalog. Because in-memory operations are usually faster than remote operations, partition projection can reduce the runtime of queries against highly partitioned tables. Depending on the specific characteristics of the query and underlying data, partition projection can significantly reduce query runtime for queries that are constrained by partition metadata retrieval.

Overview of Athena partition projection:

Reference Image

via - Reference Link

Incorrect options: