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

Installing and Configuring RDF
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
3-18
Online Product Initialization
If you can afford to stop your applications long enough to obtain a TMF shutdown
timestamp, it is recommended that you still use that method.
Determining a Valid inittime Value
When using the INITTIME parameter, it is important that you specify a valid inittime
value.
To do so, first issue a STATUS RDF command and take note of the highest updater RTD
time. Then round that RTD time up to the next higher minute (0:43 becomes 1:00, 1:27
becomes 2:00, 3:04 becomes 4:00, and so forth). Finally, subtract that rounded-up time
from the current system time shown in the status display.
inittime := (current-system-time — rounded-highest-updater-RTD-time)
RDFCOM then subtracts an additional three minutes from the specified timestamp. This
is to ensure that the extractor’s starting position is at a point in the MAT where RDF had
previously sent audit information to the backup system and the updaters had applied it to
the backup database. This practice guarantees that no audit information will be lost
during initialization.
When you include the INITTIME parameter in the INITIALIZE RDF command,
RDFCOM initiates a backward scan of the MAT searching for the first commit or abort
record whose timestamp is less than the specified
inittime . When RDF is
subsequently restarted, some of the audit information will be reapplied to the backup
database. This does not cause any inconsistencies between the primary and backup
databases, but rather ensures that they stay completely synchronized with one another.
Special Considerations
When using this form of the INITIALIZE RDF command, there are three special cases
which you might encounter.
Enscribe Create Records
If the previous version of RDF performed an Enscribe create operation on the backup
system prior to execution of the INITIALIZE RDF command and the extractor’s restart
position in the MAT precedes the associated Enscribe create record in the MAT, the
updater processing that record will report a File System error 10 (File Already Exists)
and you must purge the existing file. The updater will continue to report the error until
you have purged the file.
Stop-RDF-Updater Records
Stop-RDF-Updater records in the MAT are associated with committed SQL DDL
operations performed on the primary system with the SHARED ACCESS option.
Although such operations can be performed on the primary system without stopping
your applications, they must be performed manually on the backup system after all
updaters have shut down in response to the same Stop-RDF-Updater record.
As a general rule, you should not initialize RDF to an
inittime if you recently
performed a SQL operation with SHARED ACCESS on the primary system. For
example, suppose you have a SQL table (tableA) that contains the range of keys A