A search engine may maintain a list of derived metadata. When an event occurs that requires updating a search index, the search engine can determine which metadata is derived metadata and take appropriate actions with respect to the derived metadata. For example, if a request is received to update the index for a particular object, the search engine may protect the derived metadata from change while updating the other metadata in the index. As another example, if a request is received to update the text content for the object, the search engine may change the text content and the derived metadata. By identifying derived metadata, the search engine can protect the derived metadata from change when a request is received that otherwise causes metadata to change and can change the derived metadata when a request is received that would otherwise not change the metadata portion of the index.