The answer is reducing columns in the query and using a single date dimension table for all date columns. These two DirectQuery optimization practices minimize data transfer and avoid multiple expensive joins against the source database, directly addressing performance bottlenecks in Power BI. On the PL-300 exam, this question tests your understanding of how DirectQuery pushes queries to the source—reducing columns limits the data pulled, while a single date table prevents redundant table scans. A common trap is assuming calculated columns are safe (they are pushed to the source but can still degrade performance), or that disabling relationships helps (it breaks model integrity). Bidirectional filtering is also a known performance risk. For the exam, remember the mnemonic “Less is More”: fewer columns and fewer date tables mean faster DirectQuery.
PL-300 Model the data Practice Question
This PL-300 practice question tests your understanding of model the data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 Power BI data model for a manufacturing company. Which TWO practices help optimize performance when using DirectQuery?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reduce the number of columns in the fact query to only those needed
Option A is correct: Reducing columns in the query reduces data transfer. Option C is correct: Using a single date table avoids multiple joins. Option B is wrong because calculated columns in DirectQuery are pushed to source but can degrade performance. Option D is wrong because disabling relationships is not a best practice. Option E is wrong because bidirectional filtering can cause performance issues.
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.
✗
Disable relationships between tables to reduce query complexity
Why it's wrong here
Relationships are necessary for correct filtering.
✗
Create calculated columns in Power Query instead of in DAX
Why it's wrong here
Calculated columns in Power Query are still materialized and may not improve performance.
✓
Reduce the number of columns in the fact query to only those needed
Why this is correct
Minimizes data transfer from the source.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable bidirectional cross-filtering for all relationships
Why it's wrong here
Can degrade performance and cause ambiguity.
✓
Use a single date dimension table for all date columns
Why this is correct
Reduces the number of joins and relationships.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which PL-300 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.
Model the data — This question tests Model the data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Reduce the number of columns in the fact query to only those needed — Option A is correct: Reducing columns in the query reduces data transfer. Option C is correct: Using a single date table avoids multiple joins. Option B is wrong because calculated columns in DirectQuery are pushed to source but can degrade performance. Option D is wrong because disabling relationships is not a best practice. Option E is wrong because bidirectional filtering can cause performance issues.
What should I do if I get this PL-300 question wrong?
Identify which PL-300 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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company has a Power BI semantic model that uses DirectQuery to a SQL Server database. The model contains a large fact table with sales data. Users report that reports using this model are slow. Which design change would most improve query performance?
easy
A.Remove all relationships between tables.
B.Switch the model to Import mode.
✓ C.Remove unnecessary columns from the fact table.
D.Disable the 'Reduce queries' option in report settings.
Why C: Option C is correct because removing unnecessary columns from the fact table reduces the amount of data that must be transferred from SQL Server to Power BI for each query. In DirectQuery mode, every report interaction sends a query to the source database, so fewer columns mean smaller result sets and faster query execution. This directly addresses the performance bottleneck caused by a large fact table without changing the underlying storage mode.
Variation 2. A company has a Power BI semantic model that uses DirectQuery to a SQL Server database. The model includes a large fact table with 100 million rows. Users are experiencing slow report performance. Which THREE actions should the developer take to improve query performance?
hard
✓ A.Configure incremental refresh to limit data retrieved per query.
✓ B.Create indexes on columns used in filters and relationships.
✓ C.Remove unused columns from the fact table.
D.Hide columns that are not needed in reports.
E.Add calculated columns to precompute aggregations.
Why A: Option A is correct because incremental refresh limits the amount of data retrieved per query by partitioning the fact table into smaller, manageable date ranges. In a DirectQuery model, this reduces the volume of data scanned by SQL Server for each query, directly improving report performance by minimizing the data transfer and query execution time.
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This PL-300 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 PL-300 exam.
Question Discussion
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