RDF/IMP, IMPX, and ZLT System Management Manual

Online Database Synchronization
HP NonStop RDF/IMP, IMPX, and ZLT System Management Manual—524388-002
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Updater Phase 2
image record (which is stored in all image trails by the receiver). All transactions that
might have been started during the create/load or backup operations are now finished.
Upon completion of phase 1, part 3, the extractor logs message 768.
Phase 2
Phase 2 completes when the extractor is certain the synch-complete image record has
been successfully written in all image trails, and the extractor’s restart location is at a
point in the audit trail following the TMP control point record associated with the
completion of phase 1, part 3, above.
Upon completion of phase 2, the extractor logs message 782.
Updater Phase 2
You cannot start the updaters until the extractor has completed phase 2.
Phase 2 completes when the updater encounters the synch-complete image record in
the image trail. At that time the updater has processed all audit information that might
have been generated during the load or backup operation, and synchronization is
complete for the associated database volume.
Upon completion of phase 2, the updater logs message 782.
Extractor Restart Considerations During
Online Database Synchronization
A number of circumstances can cause the extractor to restart during online database
synchronization, such as a primary CPU failure affecting either the extractor or receiver
process. Whenever the extractor encounters a restart condition it automatically
recovers and resumes its synchronization functions. Where it resumes, however,
depends upon where it was when the restart condition occurred.
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If the restart condition occurs prior to the start of phase 1, the extractor resumes
wherever the receiver tells it to.
Note. TMP control points are generated as the result of transaction activity. For high rates of
transaction activity, the TMP control points might be only 1 or 2 minutes apart. For lower rates,
they might be 5 to 10 minutes apart. On a completely idle system, TMP control points can be
approximately 30-60 minutes apart. Therefore, if your applications and TMF are idle or nearly
so, it could take an hour or more for the extractor to encounter two TMP control points.
Note. If you are replicating only the master audit trail (MAT), you may start the updaters as
soon as the extractor issues its 782 event message. If you are also replicating one or more
auxiliary audit trails, however, you must also wait for all of the auxiliary extractors to report 0:00
RTD times before starting the updaters.