DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 gaming company uses Amazon DynamoDB to store player profiles and game state. The access patterns include: (1) lookup by player ID, (2) query by game ID for recent games, and (3) leaderboard queries sorted by score. The current single-table design is causing hot partitions on the leaderboard queries. What design change should the company implement to resolve hot partitions?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a GSI with the game ID as the partition key and a composite sort key of score and timestamp.
Option C is correct because creating a Global Secondary Index (GSI) with game ID as the partition key and a composite sort key of score and timestamp allows efficient leaderboard queries without hot partitions. This design distributes write activity across multiple partitions by game ID, while the composite sort key enables sorted queries by score and timestamp within each game, avoiding the hot partition issue caused by the original single-table design.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Increase the read capacity units (RCUs) on the base table to handle the load.
Why it's wrong here
Increasing capacity does not resolve hot partition caused by uneven write distribution.
✗
Enable DynamoDB Accelerator (DAX) to cache frequent leaderboard queries.
Why it's wrong here
DAX caches reads, not writes; hot partitions are write-related.
✓
Create a GSI with the game ID as the partition key and a composite sort key of score and timestamp.
Why this is correct
GSI distributes write activity and allows efficient sorted queries per game.
Related concept
Read the scenario before looking for a memorised answer.
✗
Shard the table by player ID and use application-level aggregation for leaderboards.
Why it's wrong here
Player ID sharding does not help leaderboard queries which need aggregation across players.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse caching solutions (like DAX) with architectural fixes for hot partitions, failing to recognize that caching does not eliminate the underlying partition-level contention caused by a skewed access pattern.
Detailed technical explanation
How to think about this question
Under the hood, a GSI with a composite sort key (e.g., score#timestamp) allows DynamoDB to perform efficient range queries and sorted results using the Query API, which is optimized for such access patterns. The partition key (game ID) ensures that write traffic for leaderboard updates is distributed across multiple partitions, while the sort key enables ordering by score and timestamp without scanning. In real-world scenarios, this design is critical for gaming leaderboards where thousands of players update scores simultaneously, as it prevents a single partition from becoming a bottleneck.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a GSI with the game ID as the partition key and a composite sort key of score and timestamp. — Option C is correct because creating a Global Secondary Index (GSI) with game ID as the partition key and a composite sort key of score and timestamp allows efficient leaderboard queries without hot partitions. This design distributes write activity across multiple partitions by game ID, while the composite sort key enables sorted queries by score and timestamp within each game, avoiding the hot partition issue caused by the original single-table design.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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