Embodiments are directed towards a method and a computer server for receiving assertions, wherein an assertion can have a functional property such that for a given subject and a given property the object has a single value at any time, maintaining a knowledge base that includes (1) a history table that stores previously received assertions, and (2) a snapshot table that stores currently valid assertions, maintaining a snapshot cache in memory that stores a subset of the assertions in the snapshot table, initiating a processing cycle, selecting an assertion for processing, generating an assertion tuple that corresponds to the selected assertion, determining that the property of the selected assertion is functional, writing a retraction tuple to the history table, writing the assertion tuple to the snapshot table; and writing the assertion tuple to the history table.