ImportData - Reload after a transform expression change



I would like to know more about the import data and more precisely how the merge data update mode works.

On an environment, I made a first data load using the c3Tools, that worked as expected and could see the data loaded properly when I fetched the results. I then updated a transform expression in one of my transform types and provisioned. I expected to see the new field values resulting from the new transform expression after a new data load but they weren’t changed. The logs (Upload / Process) show no error and when I removed the value myself using a merge and after a new data load I could see the new value.

Is there a diff applied on the new data coming from the data load and the stored one or do we just fill the missing field values with the one coming from the data load?

The environment runs the 7.8 version.


Transform changes are only applied to the new data. You will have to reload the old file(s) if you want the changes applied for existing data.


Sorry if I wasn’t clear enough, I reloaded the initial files from which the persisted data were creating from after the transform changes as you suggested. I expected the result of the new transform expression to be merged into the persisted data but it was still the previous value.


The best way is to wipe and reload. What does the stats on SourceFile say when you reload the file? Does it say it updated the records?


It updated some but not the ones I was expecting to be updated. Wiping should do the trick but I want the new values to be merged into the persisted ones. If I could avoid having to wipe and reload every time an expression changes that would be great.