Forum Discussion
DAX column vs Power QUery model column - performance
Hello,
Is there a performance difference between having calculated DAX column vs one that was created using same logic but in Power query (M). By performance I mean both, storage, memory consumption, CPU, additional recalculations if any.
Best
Hi AdamMarczak,
M is a mashup query language used to query a multitude of data sources. It contains commands to transform data and can return the results of the query and transformations to either an Excel table or the Excel or Power BI data model. DAX stands for Data Analysis expressions. DAX is the formula language used in Power Pivot and Power BI Desktop. DAX uses functions to work on data that is stored in tables. Some DAX functions are identical to Excel worksheet functions, but DAX has many more functions to summarize, slice and dice complex data scenarios. They have different functions, for a same calculated column using DAX, maybe it needs several steps to get the result using M language. Sometimes you need to created a calculated column using several functions in DAX, while it's easier and more quick. So the performance of DAX and Power Query are uncompariable based on my understanding, it depends on the requirements. They have their own advantages. Please review the following articles.
The article:The VertiPaq Engine in DAX describes the how DAX works.
The difference between DAX and M: Dax or M Language
Best Regards,
Angelia
1 Reply
v-huizhn-msftMicrosoft Employee
Hi AdamMarczak,
M is a mashup query language used to query a multitude of data sources. It contains commands to transform data and can return the results of the query and transformations to either an Excel table or the Excel or Power BI data model. DAX stands for Data Analysis expressions. DAX is the formula language used in Power Pivot and Power BI Desktop. DAX uses functions to work on data that is stored in tables. Some DAX functions are identical to Excel worksheet functions, but DAX has many more functions to summarize, slice and dice complex data scenarios. They have different functions, for a same calculated column using DAX, maybe it needs several steps to get the result using M language. Sometimes you need to created a calculated column using several functions in DAX, while it's easier and more quick. So the performance of DAX and Power Query are uncompariable based on my understanding, it depends on the requirements. They have their own advantages. Please review the following articles.
The article:The VertiPaq Engine in DAX describes the how DAX works.
The difference between DAX and M: Dax or M Language
Best Regards,
Angelia