DP-203 Design and implement data storage Practice Question
You are a data engineer at a financial services company. The company uses Azure Cosmos DB for NoSQL to store customer transaction data. The data is partitioned by customerId. The application team needs to run analytical queries that aggregate transactions by date across all customers. These queries are currently slow and consume high RUs. You need to enable faster analytical queries without impacting the transactional workload. What should you do?
⚠ Common exam trap
Many candidates think increasing RU/s or changing the partition key is a simpler fix, but the DP-203 exam specifically tests the understanding that analytical workloads must be isolated from transactional workloads using a dedicated analytical store like Synapse Link.
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
✓
Enable the Azure Cosmos DB analytical store (Synapse Link) and query the data using Azure Synapse Serverless SQL.
Enabling the Azure Cosmos DB analytical store (Synapse Link) creates a separate column-oriented store optimized for large-scale analytical queries without consuming RUs from the transactional workload. By querying this analytical store using Azure Synapse Serverless SQL, you can run fast aggregations across all customers by date while the transactional container remains unaffected.
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 provisioned RU/s on the container to handle both transactional and analytical queries.
Why it's wrong here
Raising RU/s gives analytical scans more throughput but they still consume the same shared budget, so transactional latency suffers and cost rises. It is tempting because it addresses throttling, and would be correct if the workload were uniformly transactional with no requirement to isolate analytics.
- ✗
Change the partition key to /date to optimize for analytical queries.
Why it's wrong here
Repartitioning by /date does not remove the cross-partition fan-out for per-customer transactional reads and forces a full data migration. It is tempting because date is the analytical filter, and would be correct if the dominant workload were date-range queries rather than customer-keyed transactions.
- ✗
Create a materialized view using the change feed and store aggregated data in a separate container.
Why it's wrong here
A change-feed materialised view is a custom, eventually consistent pipeline that duplicates storage and maintenance effort, and the stem asks for the built-in analytical capability. It is tempting because pre-aggregation genuinely speeds repeated queries, and would be correct when no native analytical store is available.
- ✓
Enable the Azure Cosmos DB analytical store (Synapse Link) and query the data using Azure Synapse Serverless SQL.
Why this is correct
Enabling the analytical store (Synapse Link) replicates NoSQL data into a column-oriented store, separate from the transactional row store. Azure Synapse serverless SQL then queries this columnar copy, so cross-partition aggregations by date avoid consuming RUs on the transactional workload — satisfying the isolation constraint.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-203 practice question is part of Courseiva's free Microsoft 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 DP-203 exam.