Power BI 778 Performance Optimization and Troubleshooting

Question 1

Which Power BI storage mode loads all data into the in-memory VertiPaq engine for the fastest query performance?

Accepted Answer

Import

Answer

Import mode physically copies data into Power BI's in-memory VertiPaq engine, enabling the fastest query performance since no source queries are needed at report time.

Question 2

Which built-in Power BI Desktop tool records and displays the rendering time for each visual on a report page?

Accepted Answer

Performance Analyzer

Answer

Performance Analyzer, found in the View ribbon, records the time each visual takes to render, including DAX query time, DirectQuery time, and other overhead.

Question 3

What Power BI feature partitions historical data and refreshes only the most recent portion, reducing refresh duration for large datasets?

Accepted Answer

Incremental refresh

Answer

Incremental refresh partitions data by a date/time column and only refreshes recent partitions, dramatically cutting refresh time for large historical datasets.

Question 4

What is 'query folding' in Power Query?

Accepted Answer

Pushing transformation steps back to the data source to execute natively

Answer

Query folding occurs when Power Query translates your transformation steps into a native source query (such as SQL), allowing the source system to perform the work rather than Power BI.

Question 5

What is a common performance drawback of excessive bidirectional cross-filtering in a Power BI data model?

Accepted Answer

It can create ambiguous filter paths, leading to slower queries and unexpected results

Answer

Bidirectional cross-filtering multiplies the filter propagation paths the engine must evaluate, causing ambiguity and performance degradation in complex models.

Power BI 778 Practice Test

Power BI 778 Practice Test

Power BI 778 Performance Optimization and Troubleshooting