SQL/MX 2.x Installation and Management Guide (H06.10+, J06.03+)

Managing an SQL/MX Distributed Database
HP NonStop SQL/MX Installation and Management Guide—544536-007
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Changing Network Environments
running on a remote note. Local programs can update or retrieve remote data directly
through NonStop SQL/MX. NonStop SQL/MX uses the remote I/O features of the
Guardian file system and disk process.
Alternately, when you need to update data stored on a remote node, you can send a
message containing an update request to an application on that remote node.
Ultimately, this issue might be one of performance and processing power distribution
across nodes.
A key advantages of using an application process on a remote node for distributed
processing is to reduce the amount of data sent across communication lines. One
message makes the request of the remote application process. Then that application
process manages all access to, and updating of, the remote data. This approach
reduces message traffic on slower communication lines and increases performance.
Changing Network Environments
Network environments are often subject to change. Nodes can be added or removed,
system configurations at each node can change, NonStop operating systems can be
upgraded independently at each node, communication line speeds or types can
change, and the needs of the node with respect to the database or application can
change.
Many of these changes do not affect the SQL/MX database or environment and need
not concern you if you are a system manager. Certain changes, however, can cause
problems or affect the SQL/MX environment and should be anticipated.
Consider these changes on a case-by-case basis:
•
A new node is added to the network. This addition does not affect the existing
database scheme. To access this node and incorporate it into the overall
environment, however, network passwords and security must be added to all other
nodes. Catalogs on existing nodes must be registered on the new node to make
the catalogs and their underlying objects visible to the node. After NonStop
SQL/MX is initialized on this node, register the catalogs from other nodes on the
new node, and then you can place new objects that you create in those catalogs
on this new node.
•
An existing node is permanently removed from the network. Move all object data
on this node to other nodes before dropping the objects and removing the node. If
the objects are table or index partitions, use the MODIFY utility to move the data to
another node before dropping the objects and removing the node.
•
A node needs to be renamed. Changing a node name can be difficult or impossible
to do because the node name is embedded in the file labels and stored in the
metadata.
•
The operating system at a node is updated. Usually nodes run compatible but
different operating systems. Consult the current software release documents for
compatibility issues between operating system releases. In some cases, upgrading