SQL/MX 3.2 Management Manual (H06.25+, J06.14+)

Table Of Contents
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 the operating system release imposes
compatibility issues on the database. For more information, see “The SQL/MX Environment”
(page 24).
Communication to a node is lost. Nodes can become unavailable for a variety of reasons.
For planned outages, you should systematically make inactive all network transactions to the
affected node before taking it offline. For unplanned outages, transactions are rolled back by
NonStop SQL/MX as errors and are reported as communication problems. Sometimes, you
might need to use one of the TMF interfaces (for example, TMFCOM) to manually back out
the transactions. After communications are restored, transactions can resume and proceed
normally.
Recovery takes place for a system crash on a single node. If a node crashes, it can be recovered
by using a TMF recovery method. HP recommends that you initiate the START TMF,
TRANSACTIONS OFF operation at the crashed node. This approach enables TMF to resolve
any network-distributed transactions active at the time of the crash and to attempt volume
recovery.
Keeping TRANSACTIONS OFF in effect during this procedure enables the function to complete
successfully, before new transactions are introduced to the database. TMF does not allow new
transactions to start before START TMF is completed because new transactions require network
transaction resolution and volume recovery. Another important reason for keeping
TRANSACTIONS OFF is to provide the system administrator time for additional recovery
operations, as needed, before the applications can start transaction activity. For more
information, see the TMF Planning and Configuration Guide.
A number of situations can cause severe problems with the consistency of an SQL/MX
database. Various techniques can resolve these problems. You should not, however, attempt
these operations without help from your service provider:
Recover a node with distributed objects by using the TIME option of TMF. This procedure
can cause an inconsistent database.
Perform a RESTORE of objects on a node, such that the restored objects would not be
consistent with the rest of the database.
Use the MXTOOL GOAWAY utility on portions of a network database. This procedure
can leave unresolvable references in other metadata.
If a situation arises that you think might affect the network-distributed SQL/MX database,
contact your service provider for additional information.
Managing Mixed Versions of NonStop SQL/MX
SQL/MX Release 3.2 does not support interoperability with either SQL/MX Release 2.x or SQL/MX
Release 3.0 or SQL/MX Release 3.1 in a distributed database environment. You cannot perform
queries, through embedded SQL or dynamic SQL, from a node that runs SQL/MX Release 3.1 on
Managing Mixed Versions of NonStop SQL/MX 279