RDF/IMP and IMPX System Management Manual (RDF 1.3+)

Online Database Synchronization
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
7-5
Database Considerations When Synchronizing
Entire Databases
•
Index Tables. With regard to index tables, there are several considerations for
relative and key-sequenced tables. Regardless of base table type, you cannot load an
index table by itself. Index tables can only be loaded when the associated relative or
key-sequenced table is loaded.
If you want the associated index tables loaded you must create the empty index
tables before issuing the LOAD command. When you load the base table, the index
tables are loaded automatically.
If you do not create the index tables before issuing the LOAD command, they are
ignored. If that happens, you must create them on the backup system before issuing
the START UPDATE command (if you do not do this, the affected updaters will
have to wait for you to create the index tables and will thereby fall behind the other
RDF processes).
Different SQL/MP Product Versions
If you have different versions of the SQL/MP product on your primary and backup
systems, refer to the Compaq NonStop™ SQL/MP Version Management Guide for
information about what you can do and how to do it.
Three of the more common issues are as follows:
•
If your primary system has a higher version of the SQL/MP product than the backup
system, then the tables on the primary system must not make use of features not
supported by the lower product version. Failure to comply with this will result in
errors when attempting to create the duplicate tables.
•
You can create the duplicate tables on the backup system and then load them over
the network from the primary system, but you must be knowledgeable about issues
regarding differences in table and catalog versions. Consult the Compaq NonStop™
SQL/MP Version Management Guide.
•
You can create and load the duplicate tables on the primary system and then move
them to the backup system using SQLCI DUP commands or BACKUP/RESTORE
and tapes. In either case, however, the tables must be registered in a catalog on the
backup system. Again, you must be knowledgeable about issues regarding
differences in table and catalog versions. Consult the Compaq NonStop™ SQL/MP
Version Management Guide.
Moving Duplicated Tables and Files to the Backup System
If you created the duplicate files and tables directly on the backup system and loaded
them from the primary system, you can start the RDF updaters without any further
considerations.