Oracle7 Server Distributed Systems Volume II: Replicated Data
Downgrading and the Advanced Replication Option
This section describes what to do after downgrading Oracle.
Additional Information: For instructions on how to upgrade and downgrade the version of your Oracle Server, see the README file provided with your Oracle Server.
Two distinct steps are performed by the downgrade scripts:
1. The object group and all objects replicated in the object group are unregistered if the group name is not an existing schema name.
2. The remaining replicated objects are unregistered as replicated objects if the name of the replicated object's owner does not correspond to the object group name.
Note: There may be situations in which the object group's name is the same as the object owner's name, but the object group includes objects from multiple schemas.
These objects are removed only from the replication catalog. The objects themselves are not deleted from the database.
Master Definition Sites or Master Sites
After the completion of the downgrade process, replication triggers are no longer valid because all replication trigger packages were dropped. All packages and package body wrappers were also dropped. This effectively blocks transactions against replicated tables until you regenerate replication support. From the master definition site, take the following steps (this should be done if any master site is downgraded):
1. Use DBMS_REPCAT.SUSPEND_MASTER_ACTIVITY() to
quiesce all object groups that are being replicated at the downgraded site(s).
2. When all object groups are quiesced and the administration queue is empty, use DBMS_REPCAT.GENERATE_REPLICATION_SUPPORT() to regenerate replication triggers and packages for all replicated objects such as tables, packages, and package bodies.
3. If jobqueues are used, wait until the administration queue becomes empty at the master definition site. Otherwise use DBMS_REPCAT.DO_DEFERRED_REPCAT_ADMIN(), first at all remote sites and then at the master definition site, to execute administration requests at all sites. This step needs to be performed only once because pre-Release 7.3 databases generate replication support in a single step.
4. Use DBMS_REPCAT.RESUME_MASTER_ACTIVITY() to unquiesce all objects groups and begin normal replication activity.
Downgrading Snapshot Sites
Updatable snapshots that use the $ST trigger will continue to operate normally. All Release 7.3 updatable snapshots that relied on a $TP package are no longer updatable. Since pre-Release 7.3 snapshot sites cannot generate replication support, these snapshots need to be unregistered and re-registered with the Symmetric Replication Facility. Pre-Release 7.3 snapshots do not generate replication support, but rather copy necessary triggers, packages and package bodies from the master site. The extraction is performed only once, when the snapshot replicated object is created.