SQL/MP Version Management Guide

Mixed Version Networks
Compaq NonStop™ SQL/MP Version Management Guide—429833-001
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Version 2 and Newer Version Software
Version 2 and Newer Version Software
Nodes running version 2 SQL software can operate in networks with remote nodes
running version 300 or newer software. SQL programs running on version 2 nodes can
access version 2 objects. They can also access version 2 catalogs that reside on remote
nodes running version 300 or newer software. Of course, all operations must follow
proper version-management rules to work properly.
The general rules determining how version 2 SQL software interacts with newer version
software on remote nodes are:
•
From a node running version 2 SQL software, you can access version 1 or version 2
objects on remote nodes running version 300 or newer software if the objects are
registered in a version 2 catalog. Because of this capability, SQL programs can
continue to execute correctly when a node in the network migrates to version 300 or
newer software.
•
From a node running version 2 SQL software, you cannot perform SQL operations
to access version 300 or newer local or remote objects. In this situation, a version
error results if you attempt to access an object whose version is newer than 2.
•
From a node running version 2 SQL software, you cannot perform SQL operations
to access remote objects registered in version 300 or newer catalogs, even if the
objects themselves are version 1 or version 2 objects. (This restriction is discussed
in more detail in Version 2 Access to Newer Version Remote Catalogs.)
•
When a CREATE CATALOG statement is issued from a node running version 2
SQL software, the command creates a version 2 catalog, regardless of the version of
the node where the catalog is to reside. For example, you can create a version 2
catalog on a node running version 315 SQL/MP.
Version 2 Access to Newer Version Remote Catalogs
Because of restrictions on access to newer version catalogs, version 2 SQL software
cannot access remote objects when the catalog in which the objects are registered is
upgraded to a newer version. This restriction has implications for users who have
networks running mixed versions of SQL.
On nodes that have upgraded their SQL software to version 300 or newer, you can
continue to use version 2 SQL software to access version 2 objects registered in version
2 catalogs.
When tables or other objects are accessed from remote nodes on mixed version
networks, an error can occur. Suppose a version 2 table has partitions on two nodes, one
running version 2 SQL software and the other running version 300 software. Also
suppose that the partition on the node running version 300 software is registered in a
version 300 catalog. If you issue a DDL statement affecting this table from the node
running version 2 software, the statement fails with a version error. In this situation, you
have two choices:
•
Issue the DDL statement from the node running version 300 software.
•
Downgrade the version 300 catalog in which the partition is registered to version 2.