SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Managing an SQL/MX Distributed Database
HP NonStop SQL/MX Installation and Management Guide—523723-004
13-9
Using Catalog References in an SQL/MX Distributed
Database
Catalog Reference Guidelines for Release 2.1 or Release 2.0
•
The node where a catalog is created contains the object metadata for all database
objects in that catalog and is the only automatic catalog reference for that catalog.
•
The object metadata for a catalog, including schema metadata and metadata
definitions, cannot be replicated from the automatic reference node to other nodes.
•
Catalog registration metadata can be replicated to other nodes. Use the
REGISTER CATALOG command from the automatic catalog reference node to
create empty catalog references on other nodes in the distributed database.
•
The node with an automatic catalog reference for a catalog has one
CAT_REFERENCES row for each node that has a reference for that catalog.
•
A node with an empty manual reference for a catalog has one
CAT_REFERENCES row for the automatic catalog reference node and one
CAT_REFERENCES row for itself.
Catalog Reference Examples
To better illustrate how user catalogs and their schemas are referenced in the system
schema tables for Release 2.1 or Release 2.0, consider this next example scenario.
A four-node network example consists of the nodes \N1, \N2, \N3, and \N4. A user
catalog CAT1, with two schemas, SCH1 and SCH2, is created on node \N1. Node \N1,
therefore, has the only automatic catalog reference to CAT1. For Release 2.1 or
Release 2.0, the object metadata for CAT1 cannot be replicated to any other nodes in
the network. However, catalog references for CAT1 can be registered for other nodes.
Suppose, for example, that you issue the REGISTER CATALOG command from node
\N1 to create catalog references to CAT1 for nodes \N2 and \N3, but not for \N4. As a
result, the system schema tables on nodes \N2 and \N3 would identify CAT1 and the
node where its object metadata is located (\N1). However, they would not have object
metadata for CAT1. Nodes \N2 and N3 would have to access this object metadata from
node \N1. Node \N4 would not see CAT1 or be able to access its object metadata.
For the contents of the system schema tables on these example nodes, see:
•
System Schema Tables on Node \N1 on page 13-9
•
System Schema Tables on Nodes \N2 and \N3 on page 13-10
•
System Schema Tables on Node \N4 on page 13-11
System Schema Tables on Node \N1
Node \N1 has an automatic catalog reference for the catalog CAT1. The system
schema tables on \N1 contain this information: