Transparent recovery of distributed-objects using intelligent proxies

摘要

A distributed-object software application is capable of recovering from a server crash. The recovery is transparent to the client objects because the client objects do not have to be re-started or re-loaded. Proxies on the client machine handle the details of communication over the network with server objects. An intelligent proxy detects a server crash when no response is received from the server object. The intelligent proxy then sends a name identifier of the server object to a locator. The locator looks up the name identifier and returns a remote reference to another running instance of the server object. If no other running instance exists, the locator loads the server object onto another server machine. The intelligent proxy uses the remote reference from the locator to establish a connection with the new server machine and a session with the new server object. The intelligent proxy stored the last state of the server object before the crash. This last state is dumped to the new server object to advance the new server object to the last state of the crashed server object. Then the new server object is used to continue processing requests from the client object. The intelligent proxy hides the server crash from the client object so that the client object does not have to be reset. Proxies for folders and component levels of a hierarchical application are used to restore a hierarchy of server objects.