The answer is to create an external table pointing to the Parquet files and use CREATE TABLE AS SELECT (CTAS) to load the data. This approach delivers the fastest Parquet load to a dedicated SQL pool because PolyBase can leverage predicate pushdown and column pruning directly on the compressed, columnar Parquet format, minimizing data movement and I/O. On the DP-203 exam, this scenario tests your understanding of PolyBase’s strengths for large-scale, high-throughput ingestion—specifically that CTAS with external tables outperforms COPY INTO for bulk loads over 1 TB, and that converting to CSV or splitting into many small files introduces unnecessary overhead. A common trap is assuming more files means faster parallelism, but Parquet’s native efficiency with CTAS avoids the metadata and read latency of tiny files. Memory tip: “CTAS + Parquet = PolyBase’s turbo button”—remember that for massive daily loads, the external table and CTAS combination is purpose-built for speed.
DP-203 Develop data processing Practice Question
This DP-203 practice question tests your understanding of develop data processing. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are designing a data ingestion pipeline for Azure Synapse Analytics using PolyBase. The source data is in Azure Blob Storage, with files in the Parquet format. The data volume is approximately 2 TB daily. You need to minimize the time to load data into a dedicated SQL pool table. Which approach should you recommend?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create an external table pointing to the Parquet files and use CREATE TABLE AS SELECT (CTAS) to load the data.
Option B is correct because creating an external table with the Parquet file format and using CREATE TABLE AS SELECT (CTAS) allows PolyBase to leverage predicate pushdown and column pruning, which reduces data movement and improves performance. Option A is wrong because splitting files into smaller chunks increases the number of parallel reads but the overhead of many small files can degrade performance. Option C is wrong because converting to CSV adds overhead and increases data size. Option D is wrong because COPY INTO is optimized for small to medium loads, while CTAS with external tables is better for large-scale loads.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Split the Parquet files into many small files (e.g., 64 MB each) to maximize parallelism.
Why it's wrong here
Many small files increase overhead and can degrade performance.
✗
Convert the Parquet files to CSV format before loading using PolyBase.
Why it's wrong here
CSV is less efficient than Parquet for PolyBase loads.
✗
Use the COPY INTO command to load the Parquet files directly into the dedicated SQL pool.
Why it's wrong here
COPY INTO is optimized for smaller loads; CTAS is better for large-scale loads.
✓
Create an external table pointing to the Parquet files and use CREATE TABLE AS SELECT (CTAS) to load the data.
Why this is correct
CTAS with external tables enables predicate pushdown and efficient column pruning.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this DP-203 question in full detail.
Identify which DP-203 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Develop data processing — This question tests Develop data processing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create an external table pointing to the Parquet files and use CREATE TABLE AS SELECT (CTAS) to load the data. — Option B is correct because creating an external table with the Parquet file format and using CREATE TABLE AS SELECT (CTAS) allows PolyBase to leverage predicate pushdown and column pruning, which reduces data movement and improves performance. Option A is wrong because splitting files into smaller chunks increases the number of parallel reads but the overhead of many small files can degrade performance. Option C is wrong because converting to CSV adds overhead and increases data size. Option D is wrong because COPY INTO is optimized for small to medium loads, while CTAS with external tables is better for large-scale loads.
What should I do if I get this DP-203 question wrong?
Identify which DP-203 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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