DP-203 Partition pruning Practice Question
You are designing a data processing solution using Azure Synapse Analytics serverless SQL pool. The solution will query data stored in Parquet files in Azure Data Lake Storage Gen2. You need to ensure that the queries are optimized for performance. Which action should you take?
⚠ Common exam trap
DP-203 often tests whether candidates know serverless SQL pool limitations; the trap is picking materialized views (a dedicated pool feature) or MAXDOP tuning, which do not address the I/O-bound nature of serverless queries.
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
✓
Partition the Parquet files by date and use partition pruning in the query.
In Azure Synapse serverless SQL pool, performance is dominated by how much data must be read from storage, since there is no persistent compute or indexing. Partitioning Parquet files by date and filtering on the partition column enables partition pruning, so the engine reads only the relevant folders instead of scanning the entire dataset. This dramatically reduces I/O and query time, making D the correct optimization.
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 MAXDOP setting in the query.
Why it's wrong here
MAXDOP governs intra-query parallelism for a single statement, not the data-scan efficiency that dominates serverless SQL pool performance over Parquet. It is tempting because parallelism sounds like a tuning lever, but serverless pools auto-scale, and the real gains come from partitioning, file sizing, and selecting only needed columns.
- ✗
Convert the Parquet files to CSV format for faster parsing.
Why it's wrong here
Converting Parquet to CSV removes columnar storage and predicate pushdown, forcing full row reads and slower scans in serverless SQL pool. It is tempting because CSV is universally readable and simple to inspect, but Parquet's columnar compression and statistics are precisely what serverless SQL pool exploits for performance.
- ✗
Create materialized views on the external tables.
Why it's wrong here
Serverless SQL pool does not support materialized views on external tables; the feature exists only in dedicated SQL pools. It is tempting because materialised views accelerate repeated queries, but in serverless the correct approach is partitioning, file compaction, and statistics on external data.
- ✓
Partition the Parquet files by date and use partition pruning in the query.
Why this is correct
Partitioning Parquet files by date lets the serverless SQL pool read only relevant folders, since partition pruning eliminates scanning of unrelated files. This directly reduces data scanned and I/O, which is the dominant performance constraint for serverless queries over Data Lake Storage Gen2.
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 |
Go deeper
Related to this question
About these practice questions
One of 509 original DP-203 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.