When an IDM is created all the documents included in the IDM are indexed. The next time the IDM is updated, does it completely recreate the index?
When an IDM is created, an index of the specified documents is created that allows accurate detection of content violations. The process initially takes time as the complete content of all indexed documents must be examined.
The next time the same IDM is refreshed (either manually or via a schedule) the indexing will be done with a differential approach. Only the delta (the difference between the original documents) will be processed. This includes new files, changed files and deleted files.