Before you can run a job with a migration resource in Oracle Cloud Infrastructure Database Migration, the migration resource must be validated.

If you enabled the Cloud Pre-migration Advisor Tool (CPAT) to run during the validation job, the CPAT report and details about any failed checks are found in the Job Details page. See Configuring Validation Options and Checking the Interactive Validation Premigration Advisor Report for more information.

Database Migration provides you with an interactive validation report with its integration with the Cloud Premigration Advisor Tool (CPAT). Using CPAT, Database Migration analyzes the source database during a migration job, and advises you about database features and constructs that are problematic, based on the specified Oracle Cloud target. CPAT runs by default and provides you with the following features and benefits:

• Warns you about any features used by your database that aren't supported in the target environment

• Makes suggestions for remedial changes and/or parameters to use for the Data Pump export and import operations

• Generates remedial scripts for failing checks that you can run against the source database

After a validation job runs, the job output displays the checks performed, descriptions of any problems, and actions you can take to resolve the issues.

To view or download the CPAT results

1. On a migration resource detail page, click Jobs, then the job name, then Phases.

2. Click the Validate pre-migration advisor phase name to open the Validation pre-migration advisor detail page.

   From this page you can download the CPAT report, view the report statistics, and drill down in the Checks list.

Checks List Operations

Filters: You can filter the checks listed using the Filters checkboxes on the left side.

Drill down on individual checks: Click a check name in the list to display details about that check from the CPAT report.

Check Details

The View check details panel shows you

• Information about the check, including the issue that caused the result shown, its potential impact on the migration, any action you can take to mitigate the issue, and if applicable, the location of a fixup script you can run on the source database.

• A Reviewed indicator, which lets you mark a check as "reviewed" so that you can see in the Validate premigration advisor list of checks whether you have completed whatever tasks you wanted to do with the check.

  Click the link in the check details to change it to a No or Yes value. The indicator does not have any impact on how the checks are processed; it is available for your convenience.

• A list of Objects that were flagged by the check as problematic.

  Some checks will show a read-only list of objects and some checks let you interactively update the objects listed.

Running Fixup Scripts

The location of the fixup script is shown on the View check details panel for an individual check.

The Fixup script location specifies where the script is located on the source database.

Running the fixup script against the source database requires sys admin privileges.

In multitenant architecture, fixup scripts should be run on the CDB. Running them on the PDB will produce an error.

Excluding Problematic Objects

After a validation run, every object listed in the View check details pane shows a No in the Is excluded column.

To exclude objects from the next validation run, you can check the boxes next to objects in the list and click Exclude selected, or you can choose Exclude all to exclude all objects that were listed in the check.

Any objects you choose to exclude will show a Yes in the Is excluded column. Objects marked Yes are ignored by CPAT in the next validation run, and they will not appear in the Objects list the next time you run the validation.

The migration's Selected Objects configuration is also updated to reflect this change. You will see a new row with the exclusion rule in the Selected Objects on the Migration details page. If you want to include this object again you must remove the rule in the Selected Objects list.

Note that Exclude all will exclude all of the objects on the page displayed, plus any objects from pages not displayed. However, if you check the first box in the checkbox column and click Exclude all, only the objects listed on the current page are excluded.

See Selecting Objects for Migration for information about explicitly including and excluding objects.

After a migration resource is validated you can run migration jobs with it in Oracle Cloud Infrastructure Database Migration.

When you start a migration job, you can configure it to pause at a specified phase, and then you can resume the job when you are ready.

When you start a migration job, a confirmation dialog opens, and there you can configure the job to pause at any point by selecting a phase in Require User Input After.

When the phase you selected to pause after completes, the job will enter a Waiting state until you resume (or terminate) the job.

If you pause after the phase Monitor Replication Lag, the transaction replication continues during the Waiting state. It will stop upon resume.

To start the job where it left off, do one of the following:

• In the Jobs table on the Migration Details page, select Resume from the Actions (three dots) menu for the job you want to resume.

• Click Resume on the Job Details page.

At this time you can select another phase after which to pause the job again.

Job Details page

On the Migration Details page, you can click Jobs, and see information about the jobs run with this resource.

You can click Download Log to view the log generated by Database Migration Service.

Below the job information details you can click the Metrics, Phases, and Unsupported Objects to get more information about the migration job.

Job Details - Phases

On a migration resource detail page, you can click Jobs, then the job name, then Phases, and see the phases of the job that have completed, are pending, and are currently running (labeled Started).

For any phase that has some error or warning text (or log) to display, the phase name is displayed as a clickable hyperlink, and the phase's action items menu includes View Details. Clicking on the phase name link or View details action opens a View phase details panel which displays the details of the error or warning

Download Log downloads the Data Pump log. Applies to jobs run in migration mode in the Export Initial Load and Import Initial Load phases.

The Validate pre-migration advisor phase is a special case, because this link opens the Validation pre-migration advisor detail page, from which you can download the Cloud Pre-migration Advisor Tool (CPAT) report, view the CPAT report statistics, and drill down in the Checks list.

For more information about the CPAT report and interactive details page, see Checking the Interactive Validation Premigration Advisor Report.

For details about the migration work flow phases, see Database Migration Job Phases.

For information about metrics, see Database Migration Metrics.

The following procedure ensures zero data loss during a read-write application switchover:

Both the source and target databases are opened read-write during the logical migration work flow. The following conditions apply:

• For read-only applications, switchover can happen immediately after GoldenGate Replicat has applied all outstanding source transactions, allowing for zero application downtime for those services.

• Read-write applications require assurance that all transactions have been applied on the target before switching the application over to ensure zero data loss.

If your application is read-write, you must do the following to ensure zero data loss:

1. Pause the migration job after phase ODMS_MONITOR_REPLICATION_LAG.

   This phase monitors Oracle GoldenGate Extract and Replicat operations until Replicat has caught up on the target database; end-to-end (E2E) replication lag should be less than 30 seconds.

2. After phase ODMS_MONITOR_REPLICATION_LAG completes and the migration job pauses, stop the workload on the source database (start of downtime).

3. Resume the migration job, scheduling another pause after phase ODMS_SWITCHOVER.

   This phase does the following:

   1. Ensures replication E2E lag is still less than 30 seconds

   2. Ensures that Extract has captured outstanding transactions on the source database

   3. Stops Extract

   4. Ensures Replicat has applied all remaining trail file data

   5. Stops Replicat

4. After phase ODMS_SWITCHOVER has completed, you can start the workload on the target database (end of downtime).

You can terminate a migration job while it is running or paused.

1. In the list of jobs on the Migration Details page, select Abort from the Actions (three dots) menu of the job you want to delete.

   You can also click Abort on the Job Details page.

2. In the Abort Job dialog, click Abort.