Is there a cause for large workflow files?

[JunePark]

Hi, 

I have a really simple workflow and I'm not sure why it's file size is so large.

It takes a long time just to move a single tool within the workflow.

Can anyone give ideas on why the file size is so large??

Thanks for your help.

[JunePark · Accepted solution]

One of the import files had lots of null columns.

After adjusting the import file(deleting null columns), the problem was solved.