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
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Managing a Network-Distributed SQL/MX Database
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Using the total available processing power of the system while balancing the
workload
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Enabling very large database objects to physically spread across multiple disk
volumes while accessed as a single object
The impact of unavailable disks on an SQL/MX query of a table partitioned across
multiple local disks depends on whether the unavailable disks are needed for the
query. If they are not, the query can complete successfully. A local query can be
compiled despite the unavailability of some of the table’s partitions if both of these
conditions are true:
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Either the query is dynamic or late name resolution of ANSI names or automatic
recompilation is required for a static query.
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All the accessed table’s metadata and the current system schema are available.
For example, suppose that the table PARTS is range-partitioned by part number across
$VOL1 and $VOL2, and the first key value for the partition on $VOL2 is 5000. If the
$VOL2 disk is unavailable, and a query attempts to select part number 1035, the query
succeeds because it needs only to access $VOL1.
Managing a Network-Distributed SQL/MX
Database
You can distribute an SQL/MX database—and the applications that access it—across
nodes in an Expand network. The database should be distributed in a way that
provides a high degree of transparency to applications and users while maintaining
high performance and availability.
An SQL/MX database or application can be distributed over a network of nodes in
several ways:
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Tables or indexes are partitioned on disk volumes located on two or more nodes.
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Tables, indexes, views, or programs reside on two or more nodes.
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A local view, referential integrity constraint, or trigger references a remote table.
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Local applications access remote tables or use a remote access path.
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Remote programs access local tables, views, or indexes.
The goals for managing a network-distributed database are:
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To share data efficiently among users located remotely from one another.
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To enable local identity and control while sharing information.
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To eliminate duplication of data.
Note. For information about managing a network-distributed SQL/MP database, see the
SQL/MP Installation and Management Guide.