Abstract: One embodiment of the present invention provides a system that uses a destination address of a packet to perform a fast lookup to determine a service that is specified by the destination address. The system initially receives a packet at an interface node in the cluster of nodes. This packet includes a source address specifying a location of a client that the packet originated from, and the destination address specifying a service provided by the cluster of nodes. The system uses the destination address to perform a first lookup into a first lookup structure containing identifiers for scalable services. Note that a scalable service is a service that provides more server node capacity for the scalable service as demand for the scalable service increases. If no identifier for a scalable service is returned during the first lookup, the system sends the packet to a server node in the cluster of nodes that provides a non-scalable service.

Abstract: One embodiment of the present invention provides a system that uses a packet distribution table to distribute packets to server nodes in a cluster of nodes that operate in concert to provide at least one service. The system operates by receiving a packet at an interface node in the cluster of nodes. This packet includes a source address specifying a location of a client that the packet originated from, and a destination address specifying a service provided by the cluster of nodes (and possibly a protocol). The system uses the destination address to lookup a packet distribution table. The system then performs a function that maps the source address to an entry in the packet distribution table, and retrieves an identifier specifying a server node from the entry in the packet distribution table. Next, the system forwards the packet to the server node specified by the identifier so that the server node can perform a service for the client.

Abstract: A method and apparatus for comparing a first set of data and a second set of data are disclosed. A subset of base data is compared to a subset of replicated data to determine discrepancies. These discrepancies are then used to modify the replicated set of data, and the replicated set of data thus becomes identical to the base set of data. Alternately, the base data is compared directly to the replicated data and differences between the base data and the replicated data are obtained. These differences are then used to modify the replicated data to become identical to the base data.

Abstract: To produce a continuous query for an append-only database, a client defined query first is converted into its minimal bounding non-decreasing monotone (hereinafter referred to as "monotonic increasing" query. This monotonic query, in turn, is converted into an incremental query, The resulting monotonically increasing incremental query then is installed on the database as a stored procedure that takes two date/time parameters (hereinafter referred to as "time" parameters), one of which (.tau.) identifies the last time the procedure was executed, and the other of which (t) identifies the current time. All database records are timestamped as of the time that they are entered into the database. Thus, in operation, more or less standard procedure calls periodically invoke each of the stored query procedures, thereby periodically executing the incremental queries over database records that have timestamps spanning successive time slots.