When should the FILTER function be replaced with KEEPFILTERS to enhance performance?

The FILTER function may need to be replaced with KEEPFILTERS to enhance performance particularly in scenarios where FILTER is used with a nested CALCULATE function.

When FILTER is employed within a CALCULATE, its context can lead to unintentional filtering or context transitions that may complicate the calculation and slow down performance. KEEPFILTERS retains the filter context of the existing filters and adds to it, rather than replacing it. This means that when using KEEPFILTERS, the overall performance can improve because it optimally manages the filtering logic, allowing for more efficient data processing and ensuring that the intended result is achieved without unnecessary recalculations.

When FILTER references a measure, or uses columns from multiple tables, or refers to a column from a single table in Import mode, the decision to switch to KEEPFILTERS is not necessarily driven by performance concerns as significantly, as those scenarios might not impose the same context complexity on the calculation as a nested CALCULATE does. In other words, the combination of CALCULATE and FILTER can create a situation where context is lost or mismanaged, making KEEPFILTERS a more efficient alternative specifically in that context.