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

The NOW clause of the INITTIME parameter causes RDF to be initialized at the current date
and time. The NOW clause simplifies initialization and configuration of a reverse RDF
environment created in response to a reverse trigger. See the example in “Example” (page 221).
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 NonStop SQL/MP or
NonStop SQL/MX DDL operations performed on the primary system with the SHARED ACCESS
parameter. 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
NonStop SQL/MP or NonStop SQL/MX operation with SHARED ACCESS on the primary system.
For example, suppose you have a NonStop SQL/MP or NonStop SQL/MX table (tableA) that
contains the range of keys A through Z and you just moved its partition boundary such that
tableA now contains only the keys A through M and a new table (tableB) contains the keys N
through Z. Suppose also that you performed this operation manually on the backup system.
If you then initialize RDF to a point in the MAT prior to the Stop-RDF-Updater record associated
with the partition boundary change and an updater encounters audit information associated a
key N through Z, the updater will report an error because it will try to apply the audit information
to tableA (which used to contain it, but now does not), and the audit information will not be
applied to the backup database. In this particular case, the database is not corrupted, but data
corruption could happen for other NonStop SQL/MP or NonStop SQL/MX DDL SHARED
ACCESS operations.
If you did recently perform a NonStop SQL/MP or NonStop SQL/MX operation with SHARED
ACCESS on the primary system and you want to initialize RDF to a inittime , you should wait
before issuing the command until you can specify an inittime that includes the three minutes
added by RDFCOM so that the starting position in the MAT is after the Stop-RDF-Updater record.
As a precaution, if RDFCOM encounters a Stop-RDF-Updater record during its backward search
of the MAT, it issues a warning message asking if you want to proceed with initialization. If you
continue the operation, the updaters will shut down when they encounter the Stop-RDF-Updater
record, at which time you should try to perform the NonStop SQL/MP DDL operation manually
again on the backup system.
TMF Shutdown Records
TMF shutdown records in the MAT do not cause a problem, except that RDF shuts down and
you must then restart it.
Online Installation and Initialization Without Stopping RDF
For the procedure described in “Initializing RDF Without Stopping TMF” (page 84), you are
required to stop RDF, delete the control subvolumes, reinitialize RDF, and then restart RDF.
Although unlikely, stopping RDF does leave you briefly vulnerable to inconsistent data on the
Initializing and Configuring RDF 85