Question 68 of 1,786
Data Store ManagementhardMultiple ChoiceObjective-mapped

DEA-C01 Global Secondary Index (GSI) Practice Question

This DEA-C01 practice question tests your understanding of data store management. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: global Secondary Index (GSI). Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company runs a streaming application on Amazon EC2 instances that writes data to an Amazon DynamoDB table (us-east-1). The data is later consumed by a reporting job that runs every hour. Recently, the reporting job has been failing with ProvisionedThroughputExceededException errors during peak hours. The DynamoDB table uses provisioned capacity with 1000 read capacity units (RCU) and 500 write capacity units (WCU). The reporting job performs scans and reads using eventually consistent reads. The application's write traffic is steady, but the reporting job's reads spike at the top of the hour. The data engineer needs to resolve the throughput exceptions without affecting the application's writes. Which solution should the data engineer implement?

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Create a global secondary index (GSI) with enough RCU for the reporting job and have the job query the index instead of scanning the table.

The reporting job is failing due to ProvisionedThroughputExceededException because it performs full table scans, consuming read capacity from the table's provisioned RCU. Since the write traffic is steady and must not be affected, increasing the table's RCU (Option B) is not ideal because it would also allow more reads, potentially impacting writes if capacity is shared. Switching to on-demand (Option D) would eliminate throttling but could significantly increase costs and does not provide dedicated read capacity for the reporting job. A read replica (Option C) is not a native DynamoDB feature. Creating a global secondary index (GSI) with its own provisioned read capacity dedicated for the reporting job (Option A) offloads the read traffic from the main table, preventing interference with writes. The job can query the GSI with eventually consistent reads, effectively using the allocated RCU on the GSI without affecting the table's capacity.

Key principle: Global Secondary Index (GSI)

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Create a global secondary index (GSI) with enough RCU for the reporting job and have the job query the index instead of scanning the table.

    Why this is correct

    Correct. Adding a GSI with its own RCU allows the reporting job to read from the index without consuming the table's RCU, avoiding throttling and not affecting writes.

    Related concept

    Global Secondary Index (GSI)

  • Increase the table's RCU to 2000.

    Why it's wrong here

    Incorrect. Increasing table RCU would allow more reads but does not isolate the reporting workload from writes and may still lead to contention.

  • Create a read replica of the DynamoDB table in a different region.

    Why it's wrong here

    Incorrect. DynamoDB does not support read replicas across regions; this is not a valid solution.

  • Switch the table to on-demand capacity mode.

    Why it's wrong here

    Incorrect. On-demand mode eliminates throttling but can be more expensive and does not guarantee performance isolation between reads and writes.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The main trap is thinking that simply increasing the table's RCU or switching to on-demand is the best solution, without considering the impact on write performance or cost. A GSI with dedicated capacity isolates read workloads.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • Global Secondary Index (GSI)
  • ProvisionedThroughputExceededException
  • Eventually Consistent Reads
  • Read Capacity Unit (RCU)

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Global Secondary Index (GSI)

Real-world example

How this comes up in practice

A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

Visual reference

Client Recursive Resolver Root DNS (13 root servers) TLD DNS (.com, .org, …) Authoritative example.com query IP addr answer

What to study next

Got this wrong? Here's your next step.

Review global Secondary Index (GSI), then practise related DEA-C01 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this DEA-C01 question test?

Data Store Management — This question tests Data Store Management — Global Secondary Index (GSI).

What is the correct answer to this question?

The correct answer is: Create a global secondary index (GSI) with enough RCU for the reporting job and have the job query the index instead of scanning the table. — The reporting job is failing due to ProvisionedThroughputExceededException because it performs full table scans, consuming read capacity from the table's provisioned RCU. Since the write traffic is steady and must not be affected, increasing the table's RCU (Option B) is not ideal because it would also allow more reads, potentially impacting writes if capacity is shared. Switching to on-demand (Option D) would eliminate throttling but could significantly increase costs and does not provide dedicated read capacity for the reporting job. A read replica (Option C) is not a native DynamoDB feature. Creating a global secondary index (GSI) with its own provisioned read capacity dedicated for the reporting job (Option A) offloads the read traffic from the main table, preventing interference with writes. The job can query the GSI with eventually consistent reads, effectively using the allocated RCU on the GSI without affecting the table's capacity.

What should I do if I get this DEA-C01 question wrong?

Review global Secondary Index (GSI), then practise related DEA-C01 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

Global Secondary Index (GSI)

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Last reviewed: Jun 20, 2026

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This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.