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
13-18
Maintaining Local Autonomy in a Network
and queries that access object data in CAT_2. Likewise, an outage of node \B does not
prevent metadata access by applications and queries that access object data in
CAT_1.
If CAT_1 and CAT_2 are tightly interrelated and if most application programs and
queries access objects in both catalogs, the configuration described in Table 13-5 on
page 13-17 would instead look like the configuration shown in Table 13-6.
In this example, confining CAT_1 and CAT_2 metadata and the applications that query
it to two nodes (\A and \B) creates a dependency on the availability of both of those
Table 13-6. Consequences of Network Node Loss, Reconfiguration 3
Node
CAT_1 and
CAT_2
User Data
Present?
CAT_1 and
CAT_2
Metadata
Present?
CAT_1 and
CAT_2
Applications
Present?
Consequences of Losing
This Node on Other Nodes
\A Yes Yes for
CAT_1
Yes,
accesses
CAT_1 and
CAT_2
From nodes \B and \C, you
cannot perform DDL
operations on objects
partitioned across node \A.
You cannot perform DDL,
DML, or utility operations on
objects whose metadata
resides on node \A, including
CAT_1 and CAT_2 objects
and programs. CAT_2 objects
not partitioned across node \A
can be accessed.
\B Yes Yes for
CAT_2
Yes,
accesses
CAT_1 and
CAT_2
From nodes \A and \C, you
cannot perform DDL
operations on objects
partitioned across node \B.
You cannot perform DDL,
DML, or utility operations on
objects whose metadata
resides on node \B, including
CAT_2 and CAT_1 objects
and programs. CAT_1 objects
not partitioned across node \B
can be accessed.
\C Yes No No From nodes \A and \B, you
cannot perform DDL
operations on objects
partitioned across node \C.
You cannot perform DDL,
DML, or utility operations on
objects whose metadata
resides on node \C.