Quick guess here; did not try any of this.
Once a persistency file is loaded, the data (facts in this case) should be accessible as expected and I take it that is what you are doing based on the question.
This should work.
bagof(user_data(Id,Email,Password,Role),user_data(Id,Email,Password,Role),Users).
Now all of the facts are in the variable Users as a list.
See: Finding all Solutions to a Goal
HTH
EDIT
I have created a few topics on this site that talk about and demonstrate using library(persistency), the most complete and accurate example code can be found in this post.