DP-203 Develop data processing Practice Question
You are troubleshooting a slow-running pipeline in Azure Data Factory that uses a Copy activity to transfer data from Azure Blob Storage to Azure Synapse Analytics. The pipeline processes about 100 GB of CSV files. The copy performance is poor even though the source and sink are in the same region. What is the most likely cause?
⚠ Common exam trap
Watch out — candidates often assume DIU settings are the primary performance lever, but for Synapse sinks, the staging/PolyBase mechanism is the critical factor that can improve performance by orders of magnitude.
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
✓
The copy activity is not using staging and PolyBase
The Copy activity in Azure Data Factory uses PolyBase or COPY statement (staging) to bulk load data into Azure Synapse Analytics. Without staging and PolyBase, the default insert method is row-by-row, which is extremely slow for large datasets like 100 GB of CSV files. Enabling staging with PolyBase allows parallel, high-throughput loading, which is essential for performance at this scale.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The copy activity is not using staging and PolyBase
Why this is correct
PolyBase dramatically improves load performance.
- ✗
The source and sink are in different Azure regions
Why it's wrong here
They are in the same region.
- ✗
The Data Integration Unit (DIU) setting is too low
Why it's wrong here
DIU affects throughput but PolyBase is more impactful.
- ✗
The source files are compressed
Why it's wrong here
Compression can actually improve performance.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Introduction to Azure Data Engineering
Key term
Azure Synapse Analytics
Azure Synapse Analytics is a cloud-based data integration, warehousing, and analytics service that brings together big data and data warehouse capabilities under one platform.
Key term
Azure Data Factory
Azure Data Factory is a cloud-based data integration service that lets you create, schedule, and orchestrate data pipelines to move and transform data from various sources to destinations.
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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.