You can use a logical standby database to perform a rolling upgrade of Oracle Database. During a rolling upgrade, you can run different releases of Oracle Database on the primary and logical standby databases while you upgrade your databases, one at a time, incurring minimal downtime on the primary database. Oracle Text takes full advantage of upgrading Text indexes during a rolling upgrade.
All CTX PL/SQL procedures are fully replicated to the standby database and, therefore, are upgraded, except with certain limitations, as described, for these procedures:
Oracle Data Guard Concepts and Administration for information on creating a logical standby database to perform rolling upgrades
Oracle Database uses rowids internally for the construction of indexes. The following CTX_DDL procedures are not fully replicated to the standby:
Only CTX_OUTPUT.ENABLE_QUERY_STATS and CTX_OUTPUT.DISABLE_QUERY_STATS are replicated. This means that if Oracle Text logging is enabled on the primary database before running an operation that causes logging, then the operation will run with logging on the primary database, but will run without logging on the secondary database.
When the following CTX_DOC procedures are used with Oracle Text Result Tables, the data stored in the tables is replicated. When these procedures are used without Result Tables, they are not replicated.
Oracle Data Guard Concepts and Administration for information on performing a rolling upgrade for minimal downtime on the primary database