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
13-14
Maintaining Local Autonomy in a Network for
SQL/MX Release 2.x
configurations with respect to their ability to minimize the consequences of node loss
on surviving network nodes.
Network Outage Failure Scenario
Suppose that you have an SQL/MX database that is distributed across three nodes (\A,
\B, and \C). The database includes two user catalogs, CAT_1 and CAT_2, which were
created on node \B and have been registered for nodes \A and \C.
Table 13-3 describes the status of each node in the network with respect to user data,
object metadata, applications for CAT_1 and CAT_2, and the effects of the loss of each
node on the other two nodes in the network:
•
The column “CAT_1 and CAT_2 User Data Present?” identifies whether user data
for CAT_1 and CAT_2 objects is present on a given node in the network.
•
The column “CAT_1 and CAT_2 Metadata Present?” identifies whether object
metadata for CAT_1 and CAT_2 is present on a given node. Only node \B, where
the catalogs CAT_1 and CAT_2 were created, contains this object metadata
because catalog and schema replication is not supported with SQL/MX Release
2.x.
•
The column “CAT_1 and CAT_2 Applications Present?” identifies whether
application programs that contain queries to CAT_1 and CAT_2 objects are present
on a given node.
•
The column “Consequences of Losing This Node on the Other Nodes” describes
how the loss of a given node affects the other two nodes in the network.