1. Program can use concurrently multiple databases, i.e. one per company's branch.
2. Data filters apply.
3. Indexing is always kept inside database. Document contents may be kept inside database (as a blob), but also in disk directories for ease of storage.
4. Full text search.
5. Search based on properties, well defined on documents.

Listing of documents, based on filters set, is provided instantly:

Typical fetch time for a search inside 1000000 documents: some milliseconds.
User can instantly open the text contained inside the document or the document photography itself, whether PDF or XPS.