DP-203 Develop data processing Practice Question
You are troubleshooting a pipeline in Azure Data Factory that copies data from an Azure Blob Storage to an Azure Synapse Analytics dedicated SQL pool. The pipeline fails with the error: 'PolyBase requires a varchar(max) column to be less than 1 MB.' Which action should you take to resolve this issue?
⚠ Common exam trap
Watch out — candidates often assume the error requires truncating data or switching to bulk insert, but the correct solution leverages PolyBase's staging feature to handle large columns without data loss.
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
✓
Configure the copy activity to use staging via Azure Blob Storage.
The error indicates that PolyBase is being used for the copy operation, and it has a limitation that varchar(max) columns must be less than 1 MB. Configuring staging via Azure Blob Storage (option B) allows the copy activity to use PolyBase with staging, which automatically splits large varchar(max) values into manageable chunks, bypassing the 1 MB limit. This is the recommended approach in Azure Data Factory for loading large string data into Synapse dedicated SQL pools.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Modify the source data to truncate varchar(max) columns to 8000 characters.
Why it's wrong here
Truncating data may cause data loss and is not recommended.
- ✓
Configure the copy activity to use staging via Azure Blob Storage.
Why this is correct
Using staging allows PolyBase to handle large varchar(max) columns by breaking them into smaller chunks.
- ✗
Increase the 'batchSize' property in the copy activity to 10000.
Why it's wrong here
Batch size controls the number of rows per batch, not column size limits.
- ✗
Disable PolyBase in the sink settings and use bulk insert instead.
Why it's wrong here
Disabling PolyBase may resolve the error but reduces performance.
Visual reference
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 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.
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.
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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.