Schemas Tab

The Schemas tab displays all schemas in the migration scope, including version details, compatibility settings, and synchronization status.

Schema Statistics

The top section displays aggregate counters:

Metric	Description
Total Schemas	Number of schema subjects discovered on the source registry
Selected Schemas	Number of subjects included in the migration
Total Versions	Sum of all versions across discovered subjects
Selected Evolutions	Number of schema evolutions selected for migration

Schema Table

A table lists every discovered schema subject with the following columns:

Column	Description
Subject	The schema subject name as registered in the source schema registry. Selected subjects display a “Selected” badge next to the name.
Version	Current version number of the subject
ID	Schema ID assigned by the registry
Type	Serialization format: JSON, AVRO, or PROTOBUF
Compatibility	Compatibility mode configured for the subject (e.g., BACKWARD, FORWARD_TRANSITIVE, FULL_TRANSITIVE)
Size	Schema size in bytes
Evolutions	Number of version evolutions for the subject

Tip

Schemas with FULL_TRANSITIVE compatibility provide the strongest guarantees during migration, as both forward and backward compatibility are enforced across all versions. Review the compatibility settings before cutover to ensure the destination registry matches the source configuration.

Cloudera Schema Registry (Tern Engine)

When the source schema registry is Cloudera, the job uses the Tern engine instead of Confluent Schema Linking. The Schemas tab adapts to reflect Tern’s behavior.

Tern-Specific Behavior

• The Type column shows only AVRO or JSON subjects. Protobuf and other types present on the source are not included; Tern does not migrate them.
• Only active (enabled) schema versions from the source’s MASTER branch appear. Disabled versions and non-default branch versions are excluded.
• Each subject row shows a per-subject sync status: Synced, Sync Error, Pending, or Skipped.
• The Promote action is available per subject once the subject reaches Synced status. Promoting makes the subject writable on the destination registry and removes it from Tern’s sync cycle for that subject.
• Schema IDs from the source are preserved on the destination. If the destination registry already contains a conflicting ID, the subject cannot be promoted until the conflict is resolved.

Tern runs on a recurring interval and picks up new subjects added to the source after the job starts.

Tern Engine Status

The overall Tern engine sync status is shown on the job’s Health tab, in a Tern Sync card that displays the engine state (Running, Paused, Error, or Idle), the time of the last sync, and the count of subjects with sync errors.

Managing Schemas During Replication

For jobs that replicate schemas through a schema exporter (Confluent source) or through Tern (Cloudera source), you can add and promote subjects from the Manage Schemas tab. This tab stays visible for the life of the job — including after every subject has been promoted — so new schemas can always be added later.

Exporter Status

The schema exporter’s overall status is shown on the job’s Overview tab, as the Schema Migration status:

Status	Meaning
Running	The exporter is active and replicating the selected subjects from source to destination.
Stopped	The exporter has been stopped — typically after every subject was promoted (see below). No subjects are replicating.

In the Schemas tab itself, each subject row shows its own sync status, and the per-row Promote action is disabled while the exporter is not running.

Adding Subjects

Each subject on the source registry shows a status that determines how it is added:

Status	Meaning	Adding it
Replicated	Already being replicated	No action available
Replicable	Available to add, no conflict on the destination	A simple confirmation, then the subject begins replicating
Conflicting	Already exists on the destination registry	A destructive force-add: the destination copy is removed and the subject is re-pushed from the source
Excluded	Matches an exclusion pattern set during job creation	Cannot be added

Newly added subjects appear in the Schemas tab and begin replicating without a page refresh.

Caution

Force-adding a conflicting subject permanently deletes the existing copy on the destination registry before re-pushing it from the source. Any changes made to that subject directly on the destination are lost. Use it only when you have confirmed the destination copy can be replaced.

Promoting Subjects

Promoting a subject makes it writable on the destination registry so consumers can produce to it and evolve it, and stops replicating it from the source.

• Promote All (N) promotes every synced subject at once. It is enabled only when the exporter is running and every selected subject is synced. Confirming flips the subjects to READWRITE on the destination and removes them from the exporter; a success notification confirms the promotion.
• Promoting the last remaining subject stops and removes the exporter entirely.

Note

If no subjects are selected, Promote All is still shown. Selecting it surfaces a confirmation listing the subjects that will be promoted, rather than failing — promoting an empty set never triggers an exporter operation or an error.

Caution

Stopping the exporter after promotion is best-effort: the promotion itself still succeeds. The stop is retried automatically, and if the exporter still cannot be stopped, an error asks you to stop it manually via Job Controls to complete the migration. The promoted subjects remain READWRITE on the destination.

Adding Schemas After Full Promotion

After every subject has been promoted and the exporter has stopped (and been removed), the Manage Schemas tab remains available so you can bring new schemas into replication. The available-schemas list includes both previously promoted subjects and any new subjects on the source.

Adding subjects at this point automatically provisions a fresh exporter (started in IMPORT mode) with the newly added subjects, then replication resumes. Once that completes:

• The exporter status returns to Running.
• The newly added subjects appear with a selected badge and begin syncing.
• Promote All becomes available again once the newly added subjects are synced.