The Open Server application programming interface (API) has been extended to enable Open Server to handle client connection migrations. The connection migration feature allows an Open Server application to dynamically distribute its load, provide transparent failover support, and, in cases where there are multiple Open Server applications that perform different functions, to redirect a client to an Open Server that can fulfill the client’s request.
The new APIs enable Open Server to start, complete, and cancel a migration request, and to react to migration messages from the client. New event handlers and thread properties indicate client migration state changes. An Open Server can also detect whether a new connection is a migrating connection and retrieve a unique identifier from the connection.
The following sections discuss connection migration concepts, and the APIs that have been introduced or modified to support connection migration and their usage:
Open Client migration is supported in ESD #8 and later versions. See “Open Client migration” for more information.
For information about existing Open Server APIs, see the Open Server Server-Library/C Reference Manual.
