replace or update?
Importing a hierarchical file gives the choice of replacing or updating. I've never understood the exact difference in behaviours. Normally my imports will only be to amend or add a small number of items, so 'update' seems appropriate. But logically, if I 'replaced' the catalogue with one that was only marginally different from the existing one, it would presumably result in an updating. However, since it's a different option, it must presumably behave differently, and there must be some reason not to use 'replace' if only minor changes are intended. Can anyone tell me what the disadvantages would be?
In my present case, however, my reason for the import is that I have changed all my product references (I had made the mistake of using prefixes and hyphens which made them unsearchable). I imagine therefore that 'update' won't do, so I must use 'replace'. Are there any problems I'm likely to run into?