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doc/design/rdataset

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+
+Need way to "dup" an rdataset (i.e. different rdataset handle, same underlying
+data).
+
+DB addnode routine should take an rdataset *, which, if non-NULL, would be
+attached to the added rdataset.
+
+Need credibility, security status.
+
+Cache security status in rdataset.  Have rdataset supply methods to get/set
+the security status.  For RBTDB, it goes something like this:
+
+	get:
+		if (cached status == pending)
+			lock node lock
+			read rdataset's status
+			unlock node lock
+			update cached status
+		return (cached status)
+
+	set:
+		require that status cannot go backwards (e.g. OK to pending)
+		lock node lock
+		write rdataset's status
+		unlock node lock
+		update cached status