NOTE: Although there are no actual prerequisites to using DAX Optimizer, we suggest you to learn what a VPAX file is to better understand DAX Optimizer. In case you already have this knowledge, you can skip this section.

A VPAX file is created by extracting the model metadata from a Power BI or Analysis Services model. These kinds of files contain all the information needed by DAX Optimizer to analyze the model and produce the list of issues.

NOTE: A VPAX file does not contain any actual data from the model. It only holds the metadata related the model’s structure.

Extraction tools

Use the following tools to create a VPAX file:

Creating a VPAX file from DAX Studio

The Model Metrics feature in DAX studio includes an Export Metrics option that creates the VPAX file.

Exporting metrics in Dax Studio

Creating a VPAX file from Bravo

The Save as VPAX button in the Analyze Model feature of Bravo for Power BI creates the VPAX file.

Creating a VPAX file in Bravo for Power BI

Creating a VPAX file from Tabular Editor 3

In Tabular Editor 3, you can use the VertiPaq Analyzer feature to create the VPAX file:

  1. Select the View / VertiPaq Analyzer menu item.
  2. Click Collect Stats in the VertiPaq Analyzer window.
  3. Click Export in the VertiPaq Analyzer window to save the VPAX file.

Using the latest version of extraction tools

DAX Optimizer is updated regularly to support the latest features of Power BI and Analysis Services. If the VPAX file is created with an old version of the extractor tools, DAX Optimizer displays a warning message because it might generate less accurate suggestions.

Creating a VPAX file in Tabular Editor

If you analyze a VPAX file created with an older version of the software, the resulting analysis may be less accurate. Therefore, we suggest updating the extraction tool to the latest version.

Last update: Apr 09, 2024