RDF/IMP and IMPX System Management Manual (RDF 1.4+)

Managing RDF
HP NonStop RDF/IMP and IMPX System Management Manual—524388-001
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Restoring the Primary System
Before application processing starts on the backup system following a successful
takeover operation, you might need to update statistics for SQL/MP database tables
and recompile SQL/MP program files.
After a takeover operation occurs, the following considerations apply to SQL/MP tables
protected by RDF:
•
Three other operations might help maintain acceptable performance for the
applications:
•
Evaluate whether to perform an update statistics operation on database tables.
•
Evaluate whether to recompile the application programs with the SQL compiler.
•
Use the CHECK INOPERABLE PLANS SQL/MP compiler option for any
necessary recompilations.
Before operations that would cause automatic SQL compilation, you can recompile
SQL/MP program files to check for compilation errors before running the programs. For
a complete description of operations that invalidate application programs, causing
automatic SQL compilation, see the HP NonStop SQL/MP Installation and
Management Guide.
Restoring the Primary System
When the failed primary system is restored to operable condition you have two
methods of resynchronizing your primary database with your backup database where
your applications are now running. One method is online, and the other is offline.
Online Method of Resynchronizing the Primary Database
When an RDF takeover operation completes, the purger process logs the RDF event
888, which specifies a Master Audit Trail position. On your primary system, you can
then execute TMF File Recovery with the TOMATPOSITION option. This option
requires a MAT position, and you use the position in the RDF Event 888. When File
Recovery completes, the database on your primary system is in the exact same state
as the database on your backup system was when the RDF takeover operation
completed.
Note that if you have an RDF Network, there are some situations where File Recovery
with the TOMATPOSITION option is not possible. If that is the case, RDF logs an RDF
Event 858 at the end of the takeover operation.
Note. If you are using the triple contingency feature, you must issue a COPYAUDIT command
after the takeover operations are complete to copy missing audit from the backup system that
has the most to the one that has the least. See Section 10, Triple Contingency
for details about
this situation.