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

Planning Database Security and Recovery
HP NonStop SQL/MX Installation and Management Guide—523723-004
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Guidelines for Configuring TMF
Some previously compiled programs or previously prepared DML statements execute
successfully when TMF is unavailable if the statements do not require TMF
transactions. These DML statements include queries (SELECT statements or cursor
operations) that specify BROWSE access on tables and views.
Nevertheless, even these queries and statements fail if automatic recompilation is
required (for example, if an object in the access path becomes unavailable).
Guidelines for Configuring TMF
Before you install NonStop SQL/MX, the appropriate product version of TMF must be
installed, configured correctly, and active for transaction processing on a system. The
guidelines discussed next apply to configuring TMF for use with NonStop SQL/MX.
Determining a Level of Data Protection
Configure TMF for the level of protection your application needs. The minimum level of
protection uses the automatic recovery features of TMF backout and volume recovery.
Audit dumps and online dumps allowing file recovery are optional.
Size Considerations
When determining the size requirements of TMF for NonStop SQL/MX, consider these
guidelines:
•
DDL statements execute within system-defined TMF transactions, generating
audit-trail entries. DDL statements that refer to large tables can generate a large
volume of audit-trail entries. Transaction volume includes database use by both
application programs and MXCI interactive capabilities. The interactive volume
might be minimal or might generate many audit-trail entries.
•
You should estimate INSERT, UPDATE, and DELETE transaction activity for each
table and view.
•
If you are performing parallel UPDATE and DELETE operations, consider
increasing the amount of audit trail space available to TMF. For more information,
see the TMF Operations and Recovery Guide.
•
If you have TMF configured to dump audit-trail files to tape, you should have at
least two tape drives available to prevent suspension of TMF transactions. If you
have only one tape drive and the drive fails, TMF suspends all new transactions if
the maximum number of audit-trail files that has been configured is reached.
Specifying TMF Attributes
When specifying TMF attributes, consider these guidelines:
•
You can define a separate audit trail for each volume or audit more than one
volume in the same audit trail.