What can I do when the full migration failed due to LOB fields?

Symptom

The out-of-memory (OOM) error is returned during full migration from an Oracle database to an Oracle-compatible tenant of OceanBase Database.

Possible causes

The migrated tables contain large object (LOB) fields.

Solution

Decrease the degree of parallelism (DOP) value and the amount of data queried each time, and increase the memory size. Procedure:

1. Log in to the OMS console.

2. In the left-side navigation pane, choose System Management > System Parameters.

3. Click the Edit icon in the Value column for the migration.checker.params.*parameter.

   Valid values of migration.checker.params.* are migration.checker.params.fast, migration.checker.params.normal, and migration.checker.params.steady. You must determine the parameter to edit based on the value of Full Migration Concurrency specified on the Migration Type page when you create the data migration task. Here, the value migration.checker.params.fast is used as an example.

4. In the Modify Value dialog box, specify the following parameters.

   Parameter	Description	Change the value
   limitator.platform.threads.number	The number of concurrent threads supported.	Decrease the value
   limitator.select.batch.max	The number of records queried each time.	Decrease the value
   limitator.image.insert.batch.max	The number of records inserted each time.	Decrease the value
   task.checker_jvm_param	JVM parameters for the checker component.	Increase the value. Example: -server -Xms64g -Xmx64g -Xmn48g -Xss256k

5. Click OK.