When do NOW() and TODAY() get updated? Bug?

[Evogelpohl]

I'm using this DAX function to make a measure that displays when the data model has been reprocessed. 

Data Set Updated Date = "Refreshed: " & Today()

However, when I publish this to PowerBI or open in PowerBI Designer - the date changes without reprocessing.

So, for example, I've just opened a PBIX file and the report notes today, 8/20 - see pic below.

But, this isn't right.  I've not re-processed this data set or refreshed it.  The same behavior occurs on the web site.  I have not set this PBIX file on a refresh schedule, yet each day this measure changes.

Is this right?

[andre]

you should capture the date in a column and not a measure.. measure is calculated at display time, column is calculated and refresh time

[Evogelpohl]

The measure is calculated at display time?  Humm.  Is this the same behavior as power pivot in excel?

Is this true for time intelligence functions as well, like period over period change or other functions that have some aspect of NOW or TODAY relative to some other date?

I'm used to writing dax in SSAS Tabular and this experience is different there.  A reprocess changes the measure, not a display update. 

[andre · Accepted solution]

if you browse your Tabular model using excel you will see measures based on now() change every time you refresh or change filter.  measures a calculated at report render time