I created a mapping variable for a mapping, but each time I run the session, the value of the variable stays the same.
You might not have included a variable function in the mapping. To change the value of a variable from session to session, use a variable function.
Or, you might have configured a value for the variable in the parameter file. When you define a value for a mapping variable in the parameter file, the Integration Service uses that value for the variable. See the session log to determine what start value the Integration Service uses for each variable.
In the parameter file, I configured values for parameters in a mapplet, but they are not being used in the session.
Mapping parameter and variable values in mapplets must be preceded by the mapplet name in the parameter file, as follows:
I cannot find the variable functions in the Expression Editor of the Rank or Aggregator transformation.
You cannot use variable functions in the Rank or Aggregator transformation. Use a different transformation for variable functions.