Exam DP-600 topic 1 question 94 discussion

Explanation here: https://learn.microsoft.com/en-us/dax/best-practices/dax-avoid-avoid-filter-as-filter-argument FILTER returns a table whereas KEEPFILTERS returns a Boolean. So, A, B and C are limitations of uses of Boolean expressions.

Correct Answer is D Reference: "It's recommended you pass filter arguments as Boolean expressions, whenever possible. It's because Import model tables are in-memory column stores. They are explicitly optimized to efficiently filter columns in this way." https://learn.microsoft.com/en-us/dax/best-practices/dax-avoid-avoid-filter-as-filter-argument

Selected Answer: B Replace FILTER with KEEPFILTERS in measures when you want to retain and respect existing filters in the current context, leading to potentially improved performance by reducing the overhead associated with creating new filter contexts.

D is correct

The answer is A we use keep filters for nesting https://learn.microsoft.com/en-us/dax/keepfilters-function-dax

The answer is D based on this page: https://learn.microsoft.com/en-us/dax/best-practices/dax-avoid-avoid-filter-as-filter-argument . Check out this Note in the given link "This article is especially relevant for model calculations that apply filters to Import tables.". Also, see this section extract in the given link : "restrictions that apply to Boolean expressions(KEEP Filters) when they're used as filter arguments. They: -Cannot reference columns from multiple tables -Cannot reference a measure -Cannot use nested CALCULATE functions -Cannot use functions that scan or return a table

KEEPFILTERS is a filter modifier that does not delete existing column or table filters in the filter context that conflict with the filters applied by the KEEPFILTERS parameter. https://community.fabric.microsoft.com/t5/Desktop/Conceptual-Question-FILTER-vs-KEEPFILTERS-vs-neither-What-is-the/td-p/1438803

The use case in which replacing the FILTER function with the KEEPFILTERS function will most likely reduce execution time is when the FILTER function references a column from a single table that uses Import mode. This scenario allows KEEPFILTERS to optimize the filter application process more efficiently than FILTER.

This is because KEEPFILTERS can efficiently maintain the current filter context on the imported table without the need to create a new table through FILTER, thus reducing the computational overhead and improving performance.

D. ref: https://learn.microsoft.com/en-us/dax/best-practices/dax-avoid-avoid-filter-as-filter-argument

I'm a bit confused, in any case I will go with A because context transition

This is a very confusing question. If a FILTER references the entire table rather than a single table, then using KEEPFILTER is a better choice, but none of the options actually specify that.

Replacing the FILTER function with the KEEPFILTERS function will reduce execution time in the use case where the FILTER function references columns from multiple tables (Option C). This is because KEEPFILTERS is more efficient when it intersects with an existing filter context, which can occur when conditions involve multiple columns (https://www.sqlbi.com/articles/using-keepfilters-in-dax-updated/)

When you replace FILTER with KEEPFILTERS, you avoid re-evaluating the entire table for each row. Instead, it leverages the existing context, resulting in better performance.

A is correct because Option A (when the FILTER function uses a nested calculate function): The FILTER function in DAX filters a table to the rows that meet the condition provided in its arguments. When FILTER is used within a CALCULATE function, it typically modifies the context in which the calculation is performed. If FILTER uses a nested CALCULATE function, it creates a context transition. Using KEEPFILTERS in this scenario can improve performance by modifying the behavior of context transition to ensure that existing filters on a table are not unintentionally removed or overridden, which can otherwise increase the complexity and computational load of the query.

he KEEPFILTERS function in Power BI is primarily designed to work with single-table or single-column filter contexts. When you use the FILTER function to reference columns from multiple tables, KEEPFILTERS may not work directly because it operates within the context of a single table or column. A is the ans

view this --> https://community.fabric.microsoft.com/t5/DAX-Commands-and-Tips/1-Diff-between-Filter-and-KeepFilters/m-p/2694220