One of those questions that's difficult to google.
We were running into issues the other day with speed of our svn repository. The standard solution to this seems to be "more RAM! more CPU!" etc. Which got me to wondering, are there any source-control systems that use a document/nosql database (mongodb, couchdb etc) for database? It seems like it might be a natural -- but I'm no expert on source-control database theory. Perhaps there's a way to configure a more recent source control to use a document db as storage?