SQL/MP Version Management Guide

Mixed Version Networks
Compaq NonStop™ SQL/MP Version Management Guide—429833-001
6-3
Newer Version Catalogs on Remote Nodes
A fallback node is created when a node running SQL reverts to an older version of the
software without first downgrading the user catalogs running on the same node. If a
node does not downgrade its user catalogs when it reverts to an older version of the
software, the objects and catalogs are no longer accessible to the older version SQL
software currently installed on the node.
In a network, if you revert to an older version of SQL without downgrading your user
catalogs, the catalogs and objects on your node also become unavailable to remote nodes
that could previously access them. When that happens, your node becomes a fallback
node.
To prevent the creation of a fallback node in a network, you must downgrade all user
catalogs before reverting to an older version of the software on the node.
Before downgrading a user catalog:
•
Drop any protection views on the catalog tables to be downgraded.
•
Drop any objects whose version would be newer than the version of the catalog after
the catalog is downgraded.
•
Drop any programs whose program catalog version would be newer than the version
of the catalog after the catalog is downgraded.
You cannot downgrade a catalog to version 1, but version 2 catalogs are compatible with
version 1 SQL software, provided you access only version 1 objects.
For detailed instructions on how to revert to an older version of SQL, see the NonStop
SQL/MP Installation and Management Guide.
Newer Version Catalogs on Remote Nodes
SQL/MP software running on a local node cannot access SQL objects registered in a
remote catalog if the version of the remote catalog is newer than the version of the
software running on the local node. A version error occurs in this situation even if the
versions of the objects being accessed are the same as or older than the version of the
SQL software running on the local node.
For example, suppose you are running version 2 SQL on a local node and that version
315 SQL/MP is running on a remote node. In this situation, your local version 2
software cannot access any objects, including version 2 objects, registered in a version
315 catalog on the remote node.
Figure 6-3
illustrates this situation.