RDF System Management Manual for H-Series RVUs (RDF 1.8)

When included, the WITH SHARED ACCESS option specifies that the DDL operation is to allow
concurrent read-write Data Manipulation Language (DML) access and read-only utility access
to the objects on which it operates during all but the final phase of the operation. For this reason,
operations specifying the WITH SHARED ACCESS option are sometimes referred to as Online
DDL operations.
The only operations that must be performed WITH SHARED ACCESS are merge partitions and
move boundaries. It is recommended that you perform all other operations with nonshared
access.
Performing Nonshared Access DDL Operations
For DDL operations that do not include the WITH SHARED ACCESS option, you can minimize
outage for the primary system applications:
1. Stop the applications that use the database being protected by RDF.
2. Stop TMF on the primary system.
3. Wait for RDF to stop.
4. Start TMF.
5. Start RDF with updating disabled.
6. Perform the DDL operations on the primary system.
7. Restart the applications.
8. Perform the same DDL operations on the backup system.
9. Issue an RDFCOM START UPDATE command.
Database administrators with a clear understanding of the underlying TMF auditing issues might
elect to skip some of these steps as long as the DDL operations and other audited operations are
performed in the correct sequence on the primary and backup systems. For example, it is not
absolutely necessary to stop TMF (and thus RDF), but it is safest to do so. As long as application
processing is stopped and the display from a STATUS RDF command shows that the RTD time
for every updater process is zero, the DDL operations can be safely applied.
NOTE: If you do not stop TMF on the primary system and wait for RDF to stop itself in response
to the TMFCOM STOP TMF command, make sure the RDF time delay (RTD) time for every
updater process is zero and that the updater processes have closed all database tables before you
start any DDL operation. To check the RTD times for the processes, issue a STATUS RDF
command. For this method to work, all applications protected by RDF must be shut down and
only the data base administrator manipulates the primary database.
Performing Shared Access DDL Operations
DDL operations that include the WITH SHARED ACCESS option, and which are performed on
the primary system, generate a special Stop-RDF-Updater audit record in the MAT. As each
updater on the backup system encounters that record in its image trail file, that updater logs an
RDF message 733 and then shuts down. When all of the updaters have done so, RDF logs a
message 908 indicating that it is now safe to perform the same DDL operations on the backup
system. Do that, and then issue a START UPDATE command.
If RDF aborts while the updaters are in the process of shutting down, check the RDF log to see
if RDF generated a message 908. If it did, then:
1. Issue a START RDF, UPDATE OFF command on the primary system.
2. Perform the DDL operation(s) on the backup system.
3. Issue a START UPDATE command on the primary system.
Whether or not RDF aborted while the updaters were shutting down, if one or more updaters
did not generate a message 733, RDF logs a message 905 indicating that you must not perform
the DDL operations on the backup system. If that happens, issue a START RDF, UPDATE ON
142 Managing RDF