We have a compressed dumpdata of 15MB upload extracting goes to 100MB. It has few models & fields that are not used in current tables.
Specifically, there are few contenttypes models which can be ignored, and one field field_ that can be ignored in model.
Django 1.5 users -ignorenonexistent which safely does the job of ignoring.
But how to do it efficiently in 1.4?
