Optimize Model Performance PL-300 Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A Power BI developer is troubleshooting a slow measure that calculates the running total of sales. The measure uses a CALCULATE with a FILTER over a large date table. Performance Analyzer shows that the visual's DAX query takes 10 seconds. What should you do to improve the query performance?

   • AIncrease the number of rows in the date table to improve the filter performance.
   • BRewrite the measure to use a time intelligence function such as TOTALYTD or DATESYTD instead of a custom FILTER.
   • CUse a calculated column for the running total instead of a measure.
   • DRemove the relationship between the sales table and the date table to avoid the filter.
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2. 32foundation · easy

   Which strategy reduces data granularity to improve model performance?

   • AUsing a larger data type for numeric columns.
   • BAdding more columns to the fact table.
   • CAggregating sales data from daily to monthly level.
   • DCreating additional relationships between tables.
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4. 33application · medium

   A Power BI report has a measure that calculates year-to-date sales. Users report that the measure is slow when used in a visual with many categories. You use Performance Analyzer and see that the visual's DAX query takes 6 seconds. You want to identify whether the bottleneck is in the measure's calculation or in the relationship between tables. What should you do?

   • AIn Performance Analyzer, copy the DAX query and run it in DAX Studio to examine the server timings and the execution plan.
   • BRewrite the measure using a different DAX function and test again.
   • CRemove the relationship between the fact and date tables and see if the query becomes faster.
   • DChange the visual to a table to see if the slowness is caused by the visual type.
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5. 34application · medium

   A report has several visuals on a page. Users say the page is slow. You open Performance Analyzer and see that one visual has a high 'DAX query' time, while others have high 'Visual display' time. What should you do to address the slowest part?

   • AIncrease the number of visuals on the page to distribute the load.
   • BRemove all filters from the page to speed up the DAX query.
   • COptimize the DAX query for the visual with high DAX time by simplifying the measure.
   • DReduce the 'Visual display' time by disabling animations.
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6. 35expert · hard

   A Power BI report has a page with a matrix visual that shows sales by product and region. The visual is slow, and Performance Analyzer shows that the DAX query takes 9 seconds. The developer notices that the query returns many rows because the matrix includes all products and regions, even those with no sales. The report should only show products and regions with sales. What should the developer do to improve performance?

   • ARemove the product and region columns from the visual and use a table visual instead.
   • BIncrease the 'Cache data for this visual' setting in the matrix visual's properties.
   • CUse a calculated column to flag products and regions with sales and filter the visual to that flag.
   • DModify the measure to return BLANK for products and regions with no sales, and enable the 'Show items with no data' option to be off.
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