Supported Operations with Automatic Schema Evolution

Automatic Schema Evolution is controlled using the DDL AUTOSCHEMA parameter, which can be added in Oracle GoldenGate Replicat to generate DDLs to update the target schema. The AUTOSCHEMA parameter is only supported for Replicat in classic and coordinated mode.

Oracle GoldenGate supports Automatic Schema Evolution for unidirectional and bidirectional topologies.

Note: DDL replication and AUTOSCHEMA are mutually exclusive in the Replicat process.

Following are the features of the DDL AUTOSCHEMA parameter for the initial load and CDC Replicat types:

• For the Replicat, processing initial load trails generated using SOURCEISTABLE parameter in the Extract parameter file, DDL AUTOSCHEMA automatically creates or replaces target tables.

• For CDC Replicat, DDL AUTOSCHEMA automatically creates or modifies target tables during CDC apply.

• Detect new objects, such as tables and collections, and detect changes to current metadata.

• Metadata-based DDL generation performed in the same way as DDL events being read from the trail file.

• Support for Oracle GoldenGate 19.1 trail format and higher

• By default, the Automatic Schema Evoulution functionality uses the best-fit data type on the target database for every source data type. You can override this default type mapping and choose a specific target column data type for selected source column names or source column type names.

• Automatic Schema Evolution takes COLMAP clause into consideration only for CREATE TABLE, ADD COLUMN and MODIFY COLUMN. See Support for COLMAP for details.

• Most databases have a fixed LOB size. For example, Oracle is 4GB, SQL Server is 2GB, MySQL has different LOB types with different maximum sizes, like tiny/medium/long clob.

  If the target LOB column cannot accommodate the source LOB column data size, then a corresponding warning message is displayed, indicating possible data truncation.