RDF/IMP, IMPX, and ZLT System Management Manual

Managing RDF
HP NonStop RDF/IMP, IMPX, and ZLT System Management Manual—524388-002
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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 NonStop SQL/MP database
tables and recompile NonStop SQL/MP program files.
After a takeover operation occurs, the following considerations apply to NonStop
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 NonStop
SQL/MP compiler.
•
Use the CHECK INOPERABLE PLANS NonStop SQL/MP compiler option for
any necessary recompilations.
Before operations that would cause automatic NonStop SQL/MP compilation, you can
recompile NonStop 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 NonStop SQL/MP 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.