I'm attempting to use CouchDB for a system that requires full auditing of all data operations. Because of its built in revision-tracking, couch seemed like an ideal choice. But then I read in the O'Reilly textbook that "CouchDB does not guarantee that older versions are kept around."
I can't seem to find much more documentation on this point, or how couch deals with its revision-tracking internally. Is there any way to configure couch either on a per-database, or per-document level to keep all versions around forever? If so, how?
The revisions in CouchDB are not revisions in the way you are thinking of them. They are an artifact of the way it appends updated data to the database, and are cleaned up upon compaction. This is a common misunderstanding.
You need to implement the revision-tracking as part of the schema/document design of your application.