Usually, a searching software is able to achieve fast search responses because, instead of search the Text directly, it searches an index. This would be the equivalent of retrieving pages in a book related to a keyword by searching the index at the back of a book, as opposed to searching the words in each page of the book.
Using GroupDocs.Search for Indexing and Searching Problem: Suppose you have 10 million documents of different file formats, e....because, instead of search the text directly, it searches an index...API supports searching for: Text occurrences Basic metadata fields...