Unit 6: Optimizing Power BI Performance - Practice Quiz

INT374 — Data Analytics With Power Bi 50 Questions
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1 What is the primary purpose of the 'Optimize' ribbon introduced in Power BI Desktop?

A. To create custom visual themes and layouts
B. To manage data relationships and cardinality
C. To provide tools for controlling visual refresh and analyzing performance
D. To write complex DAX formulas automatically

2 Which button in the Optimize ribbon prevents visuals from updating automatically while you are making changes to the report?

A. Pause Visuals
B. Stop Queries
C. Lock Visuals
D. Freeze Pane

3 When 'Pause Visuals' is active, what must a user do to see the updated data in a specific visual?

A. There is no way to update a single visual
B. Click the 'Refresh' button on the specific visual overlay
C. Switch to Data view and back
D. Restart Power BI Desktop

4 Which tool is used to record and analyze the time taken by visual elements to load and render?

A. Performance Analyzer
B. SQL Server Profiler
C. Query Editor
D. DAX Formatter

5 In the Performance Analyzer results, what does the 'DAX query' metric represent?

A. The time taken to download data from the cloud
B. The time it takes to render the visual on the screen
C. The time waiting for other operations to complete
D. The time required by the analytical engine to execute the query

6 Which of the following is NOT a category of duration shown in Performance Analyzer?

A. Network latency
B. Visual display
C. DAX query
D. Other

7 What feature in the Optimize ribbon allows you to quickly apply pre-configured settings for 'Query reduction' or 'Interactivity'?

A. Performance Tuner
B. Optimization Presets
C. Theme Gallery
D. Quick Measures

8 If you select the 'Query reduction' setting within Optimization Presets, what change is commonly applied to slicers?

A. Slicers automatically select all values
B. Slicers become invisible
C. An 'Apply' button is added to slicers
D. Slicers are converted to dropdowns

9 In Performance Analyzer, what does the 'Copy query' function allow you to do?

A. Copy the resulting data table to Excel
B. Copy the SQL or DAX generated by the visual to the clipboard
C. Copy the visual formatting settings
D. Duplicate the visual on the canvas

10 What is the meaning of the 'Visual display' duration in Performance Analyzer?

A. Time spent calculating DAX measures
B. Time required to render the visual elements (charts, graphs) on the screen
C. Time spent waiting for other visuals to load
D. Time taken to retrieve data from the source

11 Under the 'Other' category in Performance Analyzer, what is a common cause for a high duration?

A. Complex DAX calculations
B. Waiting for other visuals to finish refreshing (queueing)
C. Rendering complex maps
D. Applying conditional formatting

12 When using the Optimize ribbon, how can you force all visuals to reload data from the cache or source?

A. Close and Reopen the file
B. Click 'Optimization Presets'
C. Click 'Refresh Visuals'
D. Click 'Pause Visuals'

13 Which storage mode generally benefits most from 'Query Reduction' settings?

A. Dual Mode
B. Import Mode
C. Live Connection
D. DirectQuery

14 What happens to cross-highlighting when 'Query reduction' presets are applied?

A. It changes color
B. It becomes faster
C. It is usually disabled by default
D. It forces a data refresh

15 To use Performance Analyzer, what must you do first after opening the pane?

A. Export to Excel
B. Click 'Start recording'
C. Write a DAX measure
D. Select a visual

16 Which external tool is most commonly paired with Performance Analyzer to fine-tune DAX queries?

A. DAX Studio
B. Excel
C. Power Automate
D. Notepad

17 What file format does Performance Analyzer export its results to?

A. .XML
B. .JSON
C. .PBIX
D. .CSV

18 In the context of the Optimize ribbon, what does 'Customizing' presets allow?

A. Manually adjusting settings for slicers and filters distinct from the default presets
B. Changing the color of the ribbon
C. Changing the report background
D. Creating new DAX functions

19 Which visual type typically consumes the most 'Visual display' time?

A. Card visual
B. Maps or Scatter charts with thousands of data points
C. Simple Bar chart
D. Slicer

20 When 'Pause Visuals' is enabled, what happens to the Filter Pane?

A. Changes are pending until the visual is unpaused or refreshed
B. Changes are applied immediately
C. It disappears
D. It works normally

21 Why might a DAX query duration be 0 ms or extremely low in Performance Analyzer?

A. The query failed
B. DAX is not used in Power BI
C. The visual is broken
D. The data is being retrieved from the visual cache (already loaded)

22 How can you clear the cache to get an accurate cold-cache reading in Performance Analyzer without restarting?

A. Toggle the visual type
B. There is a 'Clear Cache' button directly in the Optimize ribbon
C. Delete the page
D. Use the 'Clear Cache' feature in DAX Studio or add a blank page then return

23 Which of the following is a symptom of a report needing optimization?

A. The report has more than 2 pages
B. Visuals take several seconds to load after clicking a slicer
C. The report uses custom colors
D. The report uses a Star Schema

24 The 'Optimize' ribbon was introduced to help report creators working specifically with which type of data models?

A. Small Excel files
B. Large models and DirectQuery sources
C. Static CSVs
D. SharePoint lists

25 Can Performance Analyzer record actions across multiple report pages?

A. Only in Power BI Service
B. Only if the pages are duplicated
C. No, it stops when you switch pages
D. Yes, it continues recording until you press Stop

26 What is the 'Apply' button on the Filter pane used for in Optimization settings?

A. To apply filter changes in bulk rather than individually
B. To apply formatting changes
C. To save the report
D. To apply the filter to all pages

27 Which element allows you to sort Performance Analyzer results by 'Total duration' or 'Action order'?

A. The Optimize ribbon settings
B. The View tab
C. You cannot sort the results
D. The sort icons in the header of the Performance Analyzer pane

28 If a visual displays a 'Loading...' spinner for a long time, which Performance Analyzer metric will likely be highest?

A. DAX query
B. Evaluation
C. Visual display
D. Copy duration

29 Using the 'Optimize' ribbon, where can you find the option to 'Add an Apply button to all slicers'?

A. Optimization Presets -> Query Reduction
B. Refresh Visuals
C. Pause Visuals
D. Performance Analyzer

30 Does the 'Pause Visuals' feature stop the data refresh from the underlying data source (e.g., scheduled refresh)?

A. Yes, but only for SQL sources
B. No, it deletes the data source
C. No, it only stops the visual rendering on the canvas
D. Yes, it stops all data movement

31 What is the benefit of disabling 'Cross-highlighting' in optimization presets?

A. It makes the report more colorful
B. It reduces the number of queries generated when selecting elements in a chart
C. It enables drill-through
D. It increases the file size

32 If 'Other' duration is high in Performance Analyzer, what is a potential fix?

A. Rewrite the DAX measure
B. Reduce the number of visuals on the page
C. Change the chart color
D. Increase font size

33 Which visual interaction setting sends the most queries by default?

A. Static Mode
B. Query Reduction
C. Full Interactivity (default)
D. Fixed Layout

34 What indicates that a visual is currently 'Paused'?

A. The visual turns black
B. The visual shows old data with no warning
C. The visual disappears
D. An overlay message says 'Visual is paused'

35 In the Performance Analyzer, can you see the performance of Custom Visuals?

A. Yes, they appear like any other visual
B. No, custom visuals are ignored
C. Yes, but only the DAX portion
D. No, only native visuals

36 What is the result of clicking 'Refresh visuals' in the Optimize ribbon while 'Pause visuals' is still active?

A. It automatically turns off 'Pause visuals' permanently
B. Nothing happens
C. It produces an error
D. The visuals refresh once, then return to the paused state

37 Which of the following is NOT a column in the exported JSON file from Performance Analyzer?

A. programmerName
B. duration
C. action
D. visualType

38 When optimizing a report, what is the recommended approach for row-level security (RLS)?

A. Test performance with RLS roles applied as it can impact query generation
B. Disable RLS for all users
C. Use RLS only on text columns
D. RLS has no impact on performance

39 If you want to permanently keep 'Apply' buttons on slicers for a specific report, where should you configure this if not using the Optimize ribbon presets?

A. View > Themes
B. Modeling > Manage Roles
C. Home > Transform Data
D. File > Options and settings > Options > Current File > Query reduction

40 How does 'Pause Visuals' help when creating a new DAX measure?

A. It writes the code for you
B. It prevents visuals from throwing errors or recalculating while the measure is incomplete or being typed
C. It increases the DAX formula bar size
D. It highlights syntax errors

41 Which of these is a best practice for optimizing data models before using the Optimize ribbon tools?

A. Use Calculated Columns instead of Measures
B. Keep all relationships bi-directional
C. Import all columns from the source
D. Use a Star Schema and remove unnecessary columns

42 In Performance Analyzer, if 'Copy query' is greyed out (unavailable) for a specific item, what does it likely mean?

A. You are not an admin
B. The visual generated no DAX query (e.g., a text box or image)
C. The visual is paused
D. The visual is too slow

43 What is the primary trade-off when using Optimization Presets set to 'Query Reduction'?

A. Better graphics at the cost of data accuracy
B. Faster refresh at the cost of security
C. Better performance at the cost of one-click interactivity
D. There is no trade-off

44 Can Performance Analyzer identify bottlenecks caused by Power Query transformations?

A. Yes, but only for Excel sources
B. Yes, under the 'ETL' category
C. No, it only analyzes the front-end report performance (DAX and Rendering)
D. Yes, directly

45 If a slicer allows 'Multi-select' with an Apply button enabled, when is the query sent?

A. Randomly
B. After every single checkbox click
C. Only when the user clicks 'Apply' after making all selections
D. When the user hovers over the slicer

46 The Optimize ribbon is available in which version of Power BI?

A. Power BI Mobile only
B. Power BI Report Builder only
C. Power BI Desktop
D. Excel Add-in only

47 What does a high 'Evaluation' time in a DAX query (seen in detailed breakdown) usually suggest?

A. Inefficient DAX code or high cardinality scans
B. Slow rendering
C. Slow internet
D. Missing fonts

48 How does limiting the number of visuals on a page help optimization?

A. It saves ink when printing
B. It reduces the number of concurrent queries the engine must process
C. It allows more colors to be used
D. It automatically fixes DAX errors

49 Can you use Performance Analyzer to compare the speed of two different visuals displaying the same data?

A. Only if they are custom visuals
B. No, it only works on bar charts
C. No, it only records the whole page
D. Yes, by recording them side-by-side or sequentially

50 If you wish to return to the default behavior after using 'Optimization Presets', which option should you choose?

A. Disable Optimization
B. Pause Visuals
C. Full Interactivity
D. Query Reduction