The argument I have against okvs-maximum-key is that it is not defined in the case of embedded OKVS where key size is not limited aka. limited only by available memory (or configuration).
Good point. Even if we did have maximum-key we wouldn't need minimum-key, because it is always "".
The use of "SOME"/"some" in commit 2fe1c762a0940da8fea7f848b0e6df6caae7adec is ... inelegant. Although anything there, including spelling out "okvs or transaction object", needs an explanation. John's excellent suggestion of 'auto-commit doesn't get around the fact that the procedures need some sort of reference to the database somewhere in their args, I agree that one overloaded argument is fine, and my suggestion of setting the value of a quoted atom to the database is truly inelegant.
In cases like this I've normally gone with "okvs-or-transaction", but "object" is always possible. In Scheme, clear is more important than short.