Configuring initial load advanced options for Oracle migrations

Oracle Cloud Infrastructure Database Migration automatically sets optimal defaults for Oracle Data Pump parameters to achieve better performance and ensure security of data.

To further tune performance, change the export modes, or rename database objects, there are several Data Pump settings that you can configure in the Migration resource Advanced Settings, Initial Load tab.

• Source data transfer mechanism: Type of dump transfer to use during Data Pump Export. The options are CURL or OCI_CLI. The default is CURL.

• Target data transfer mechanism Type of dump transfer to use during Data Pump Import. The options are CURL or OCI_CLI. The default is OCI_CLI.

• Table exists action sets the Data Pump TABLE_EXISTS_ACTION parameter, which specifies the action to be performed when data is loaded into a preexisting table.

  • Skip no changes to the preexisting table.

  • Truncate removes rows from a preexisting table before inserting rows from the Import. Note that if Truncate is specified on tables referenced by foreign key constraints, the truncate operation is changed to Replace.

  • Replace replaces preexisting tables with new definitions. Before creating the new table, the old table is dropped.

  • Append - new rows are added to the existing rows in the table

  • UNSPECIFIED: (default) Use default settings.

• Cluster is enabled by default. When enabled, Data Pump workers are distributed among the instances (nodes) in a cluster (Oracle RAC) architecture.

  If this setting is not checked, all Data Pump workers are started on either the current instance or on an instance usable by the job.

• Export parallelism degree sets the Data Pump export SET_PARALLEL degree parameter. This setting determines the maximum number of worker processes that can be used for the migration job. You use this parameter to adjust the amount of resources used for a job.

  By default, Database Migration sets source database export parallelism to (Sum of (2 x (no. of physical CPU) per node ) ) with Max 32 cap.

  See SET_PARALLEL Procedure in Oracle Database PL/SQL Packages and Types Reference for more details.

  Note: The export parallelism degree for MySQL migrations has a value of four threads. This is also applicable for the Import parallelism degree.

• Import parallelism degree, similar to Export Parallelism Degree, sets the Data Pump import SET_PARALLEL degree parameter.

  By default, Database Migration sets import parallelism for Autonomous Database to the number of OCPUs.

• Auto-create tablespaces: For ADB-Dedicated (ADB-D) and co-managed/non-ADB database targets, automatic tablespace creation is enabled by default. Database Migration validates whether automatic tablespace creation is supported on the specified target database. Oracle Autonomous AI Database Serverless targets are not supported.

  Database Migration automatically discovers the source database tablespaces associated with user schemas that are being migrated, and automatically creates them in the target database before the Data Pump import phase. Database Migration generates the DDL required to pre-create the tablespaces, creates the tablespaces on the target, and runs the generated DDL.

  With automatic tablespace creation enabled, Database Migration skips automatic creation for any tablespaces that are specified in the Metadata remaps section, or that already exist in the target database.

  Use big file: Autonomous Database systems support only BIGFILE tablespaces, so Database Migration enforces BIGFILE tablespace by default on Autonomous Database targets, and reports an error if SMALLFILE tablespaces are found. You can explicitly remap any SMALLFILE tablespaces instead.

  Extend size: enables tablespaces to AUTOEXTEND to avoid extend errors, with a default extend size of 500MB.

• Remap target: When migrating to an Oracle Autonomous AI Database Serverless target, all tablespaces are automatically mapped to DATA. You can override this by explicitly mapping tablespaces to a different target in Metadata remaps.

• Block size of target database: Optionally, when creating or updating a migration for ADB-Dedicated (ADB-D) and co-managed/non-ADB database targets, you can select the database block size for the tablespace as automatic tablespace creation is enabled by default.

  Currently, there are two possible values to select the target database block size: 8K or 16K.

• Metadata remaps lets you rename database objects during a migration job. Select the object to rename under Type, then enter the Old Value and New Value.

  Supported objects are Datafile, Schema, Table, and Tablespace.

  When migrating to an Oracle Autonomous AI Database Serverless target, all tablespaces are automatically mapped to DATA. You can override this by explicitly mapping tablespaces to a different target.

  Quota grants for individual users to tablespaces are not remapped, so you must manually create these grants for tablespace DATA.

  To rename multiple objects, click + Another Metadata Remap.

• Advanced parameters Advanced parameters section lets you specify the advanced parameters pertaining to the initial load.

  While creating migration, select a list of parameters for migration. Select the Parameter name and Parameter value from the list. Click + Another parameter to add the parameters.

  For more information, see Zero Downtime Migration Logical Migration Response File Parameters Reference .