SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A solutions architect is reviewing an application that writes millions of small records per hour to an Amazon DynamoDB table. The table uses a partition key of customer ID, and a few very large customers generate most of the traffic. During peak periods, the application receives ProvisionedThroughputExceededException errors even though total consumed capacity is below the provisioned amount. Which action will resolve the throttling MOST effectively?
⚠ Common exam trap
The trap here is assuming ProvisionedThroughputExceededException always means total capacity is too low, when it frequently signals a hot partition caused by a low-cardinality or skewed partition key.
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
✓
Redesign the table to use a composite partition key that appends a random or calculated suffix to the customer ID, distributing writes across more partitions.
The throttling is caused by hot partitions, where a few high-traffic customer IDs exceed the per-partition throughput ceiling despite ample table-level capacity. Appending a random or calculated suffix to the partition key spreads each large customer's writes across many partitions, eliminating the bottleneck. Simply adding capacity, switching to on-demand, or moving to an index with the same skewed key does not redistribute the load.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Switch the table from provisioned capacity to on-demand capacity mode so DynamoDB automatically handles all traffic spikes.
Why it's wrong here
On-demand mode removes capacity planning and scales with traffic, but it still respects per-partition throughput limits. A single hot partition key can still throttle even in on-demand mode because the physical partition has a fixed maximum. Changing capacity mode alone does not redistribute a skewed key, so the underlying problem remains.
- ✓
Redesign the table to use a composite partition key that appends a random or calculated suffix to the customer ID, distributing writes across more partitions.
Why this is correct
Hot partitions occur when a single partition key value concentrates traffic. Adding a high-cardinality suffix spreads each large customer's writes across many partitions, each with its own throughput ceiling. This directly addresses the imbalance causing ProvisionedThroughputExceededException while keeping total capacity adequate. It is the standard DynamoDB remedy for skewed access patterns.
- ✗
Create a global secondary index on the customer ID attribute and direct all reads and writes to the index instead of the base table.
Why it's wrong here
A global secondary index has its own partition key and its own throughput limits; if it reuses the same skewed customer ID as the partition key, it inherits the same hot partition problem. Indexes also add storage and write amplification costs. Redirecting traffic to an index does not solve the concentration of writes on a few key values.
- ✗
Enable DynamoDB auto scaling to increase the provisioned read and write capacity units when consumed capacity approaches the limit.
Why it's wrong here
Auto scaling adjusts table-level capacity, but the throttling stems from uneven distribution across partitions, not from insufficient total capacity. Adding capacity does not fix a hot partition because a single partition key value is limited to roughly 1,000 write capacity units per second. The errors would likely persist for the largest customers until the key design changes.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SAP-C02 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 SAP-C02 exam.