DP-203 Design and implement data storage Practice Question
You are designing a storage solution for a financial analytics platform that ingests CSV files into Azure Data Lake Storage Gen2. Analysts run complex T-SQL queries against the data using Azure Synapse Analytics serverless SQL pool. You need to minimize query cost and improve performance. What should you do?
⚠ Common exam trap
The trap here is assuming that simply changing the storage service or adding a view will optimize query cost, when the real gains come from using a columnar format and partitioning the data.
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
✓
Convert the CSV files to Parquet format and partition the data by date.
Serverless SQL pool charges based on data processed. Converting CSV to Parquet, a columnar format, allows queries to read only needed columns and push down filters, reducing data scanned. Partitioning by date further minimizes data read when queries filter on date. Together, these changes significantly lower cost and improve performance for analytical queries over file data in Data Lake Storage Gen2.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Store the CSV files in a single folder and create a view that selects all columns.
Why it's wrong here
Storing CSV files in a single folder without partitioning forces serverless SQL to scan all files for every query, increasing data processed and cost. CSV is row-based and does not support column pruning, so even queries selecting few columns read entire rows. This approach does not optimize performance or cost.
- ✗
Use Azure Blob Storage instead of Azure Data Lake Storage Gen2.
Why it's wrong here
Azure Blob Storage lacks the hierarchical namespace and POSIX ACLs of Data Lake Storage Gen2, which are important for fine-grained access control and efficient folder-level operations. More importantly, switching storage type does not address the query performance and cost issues caused by CSV format and lack of partitioning. Serverless SQL pool can query Blob Storage, but the format and partitioning remain the primary factors.
- ✓
Convert the CSV files to Parquet format and partition the data by date.
Why this is correct
Parquet is a columnar format that enables column pruning and predicate pushdown, reducing the amount of data scanned by serverless SQL queries. Partitioning by date further limits the data read when queries filter on date, directly lowering cost and improving performance. This is the recommended approach for analytical workloads in Azure Synapse serverless SQL pools.
- ✗
Enable Azure Synapse Link for Azure Cosmos DB.
Why it's wrong here
Azure Synapse Link for Azure Cosmos DB is used to create a near-real-time analytical store for operational data in Cosmos DB. It is irrelevant for CSV files stored in Data Lake Storage Gen2 and does not improve serverless SQL query performance or reduce cost for file-based data. This service is designed for a different data source and workload pattern.
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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
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.