Long before Streams, long before Goldengate, if you want to keep data between sites synchronised in some fashion, or even allow sites to independently update their data, there was the Advanced Replication facility in Oracle. An “extension” of the concept of simple materialized views (or snapshots as they were called then), you could design complete replicated environments across Oracle databases.
But it was a non-trivial exercise to do this. You had to be familiar with replication groups, replication objects, replication sites, master groups, master sites, master definition sites, deferred transactions, quiescing, updatable materialized views, replication catalogs, conflict resolution…the list goes on an on.
Much (all?) of this has been obsoleted in one way or another by Goldengate, Active DataGuard, and other simpler more powerful technologies that the Oracle database offers today. It is probably for this reason that Advanced Replication has come to a natural end of life, as noted in the 12.2 Documentation.
“Desupport of Advanced Replication
Starting in Oracle Database 12c release 1 (12.1) the Advanced Replication feature of Oracle Database is desupported.
The Oracle Database Advanced Replication feature is desupported in its entirety. The desupport of this feature includes all functionality associated with this feature: multimaster replication, updateable materialized views, hierarchical materialized views, and deployment templates. Read-only materialized views are still supported with basic replication.
Oracle recommends that you replace your use of Advanced Replication with Oracle GoldenGate.”
So if you are still hanging old to all of those old complicated Advanced Replication mechanisms…it’s time let them go.