Haystack backend using document_id as a variable
Haystack backend receiving hints (with patched Haystack that sends them)
Haystack backend: Async mode working (needs custom async library)
Improved comment
Log re-use and re-opening of databases
Reopen closed databases (database.reopen() on closed databases should throw DatabaseError, but it doesn't?)
Already initialized databases are re-initialized if they could be dead or close to dead