The answer is that the global secondary index is throttling due to uneven access patterns. This is the most likely cause because DynamoDB on-demand capacity scales automatically for the base table, but each GSI has its own independent write capacity, and if a GSI’s partition key is poorly chosen, hot partitions can exceed the index’s throughput limits, triggering ProvisionedThroughputExceededException errors even when the base table has ample capacity. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding that on-demand mode does not eliminate throttling risks for GSIs—a common trap is assuming on-demand means zero throttling everywhere. Remember that while the base table handles spikes, a GSI with a skewed access pattern remains a bottleneck. Memory tip: “GSI throttling is the hidden spike—check your index keys, not just your table.”
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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 critical Amazon DynamoDB table with on-demand capacity. The table experiences throttling errors (ProvisionedThroughputExceededException) during peak hours. The table has a global secondary index (GSI) with a different partition key. What is the MOST likely cause of the throttling?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The global secondary index is throttling due to uneven access patterns.
Option C is correct because on-demand tables can throttle if a GSI's write capacity is exceeded. Option A is incorrect because on-demand capacity scales automatically for the base table. Option B is incorrect because throttling is not due to read-heavy workloads on the base table. Option D is incorrect because partition keys are automatically managed.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The base table's write capacity is insufficient for the workload.
Why it's wrong here
On-demand tables automatically scale; throttling is rare for base table.
✓
The global secondary index is throttling due to uneven access patterns.
Why this is correct
GSIs on on-demand tables have their own capacity; hot partitions can cause throttling.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The partition key design causes hot partitions in the base table.
Why it's wrong here
On-demand tables handle hot partitions better; GSI is more likely issue.
✗
The table's read capacity is too low for the read-heavy workload.
Why it's wrong here
Throttling errors are for writes, not reads.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Management and Operations — This question tests Management and Operations — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The global secondary index is throttling due to uneven access patterns. — Option C is correct because on-demand tables can throttle if a GSI's write capacity is exceeded. Option A is incorrect because on-demand capacity scales automatically for the base table. Option B is incorrect because throttling is not due to read-heavy workloads on the base table. Option D is incorrect because partition keys are automatically managed.
What should I do if I get this DBS-C01 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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