I want to see which indices were supposed to be created in the last upgrade I ran because I get a status report message saying that some indices are missing, but when I click "Update Indices" I get an error saying "DB Error: already exists". So I'm pretty sure some of the indices are missing, but not all of them. So I want to manually create only the missing ones.
There are a number of other threads around this issue and you may find the specific advice you need if you read through them eg
or this one