System proxy databases

System proxy databases are provided which behave like user proxy databases, with some notable enhancements and exceptions. These differences are described in this section. System proxy databases are only used in an HA configuration.

The purpose of providing system proxy databases is to allow customer-written applications to run on either node in a high-availability cluster. This does not imply ’single-system image’ capability; rather, it suggests an environment in which most user-written applications will be able to execute on either node in the cluster. This means that both databases and user-created objects should be visible to both nodes. To facilitate this capability, the notion of a system proxy database was introduced in version 12.0 of Adaptive Server Enterprise.

A system proxy database has the same name as the database in the primary node which it references, and contains handling for the user-defined objects that are necessary to support the application: Proxy tables are created for each user table and view found in the primary database, and stored procedures are converted to RPCs and forwarded to the node referenced by the proxy database.