DBS-C01 Workload-Specific Database Design Practice Question
A company is running a MongoDB-compatible database on Amazon DocumentDB. The application performs frequent updates to a small subset of fields in documents. The company notices that write latency is high. What should the database specialist recommend to reduce write latency?
⚠ Common exam trap
Test-takers frequently assume scaling up hardware (Option B) or changing storage (Option D) is the default fix for high write latency, but the exam tests understanding that index overhead is the most common cause of write amplification in DocumentDB and MongoDB-compatible databases.
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
✓
Review and remove unnecessary indexes on the collection.
Unnecessary indexes impose a write penalty on every insert, update, and delete operation. In Amazon DocumentDB, each write must update all indexes on the collection, so removing unused indexes reduces the per-document write overhead and directly lowers write latency for frequent updates to a small subset of fields.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Review and remove unnecessary indexes on the collection.
Why this is correct
Fewer indexes mean less work during writes, reducing latency.
- ✗
Increase the instance size of the DocumentDB cluster.
Why it's wrong here
While this may improve performance, it does not address root cause if indexes are the issue.
- ✗
Enable multi-master writes to distribute write load.
Why it's wrong here
DocumentDB supports only single-master writes.
- ✗
Change the storage type from standard to provisioned IOPS.
Why it's wrong here
DocumentDB uses the same underlying storage; provisioned IOPS is not applicable.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.