Am pretty much new to Database activity. We are using Oracle 19C and am having only SQL Developer with me. I have a task to find and remove unused indexes from all tables of a particular owner (say owner=QTSD). Am using below query:

```
select * from ALL_INDEXES where owner='QTSD';

```

From the result, am checking LAST\_ANALYZED column and then which was analyzed last year those indexes I will drop it one by one. Is this the correct way to implement? Also does deleting the indexes need DB downtime as corresponding tables have ~100millions of data?