apache/iceberg · error · IllegalArgumentException

Invalid operator event type:

Error message

Invalid operator event type: 

What it means

TriggerManagerCoordinator receives OperatorEvents from its subtask operators. It only recognizes CheckpointTriggerEvent, TimerTriggerEvent (and LockRegisterEvent for registration); any other event type is rejected with this IllegalArgumentException, since the coordinator cannot meaningfully process it.

Source

Thrown at flink/v2.1/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/TriggerManagerCoordinator.java:48

  TriggerManagerCoordinator(String operatorName, Context context) {
    super(operatorName, context);
    LOG.info("Created TriggerManagerCoordinator: {}", operatorName);
  }

  @Override
  public void handleEventFromOperator(int subtask, int attemptNumber, OperatorEvent event) {
    runInCoordinatorThread(
        () -> {
          LOG.debug(
              "Handling event from subtask {} (#{}) of {}: {}",
              subtask,
              attemptNumber,
              operatorName(),
              event);
          if (event instanceof LockRegisterEvent) {
            registerLock((LockRegisterEvent) event);
          } else {
            throw new IllegalArgumentException(
                "Invalid operator event type: " + event.getClass().getCanonicalName());
          }
        },
        String.format(
            Locale.ROOT,
            "handling operator event %s from subtask %d (#%d)",
            event.getClass(),
            subtask,
            attemptNumber));
  }
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Send each event type to the correct endpoint: LockReleaseEvent goes to TriggerManagerOperator, trigger/lock-register events to the coordinator.
2. Ensure the Iceberg Flink runtime version is identical across the job (job jar and cluster classpath).
3. Restart the job from scratch or from a savepoint produced by the same version instead of mixing versions during restore.
4. Check that no custom operator events are being routed to the maintenance topology's coordinator.

Example fix

// before
targetCoordinator.sendOperatorEvent(new LockReleaseEvent(lockId));
// after
targetOperator.sendOperatorEvent(new LockReleaseEvent(lockId));

if (!(event instanceof CheckpointTriggerEvent) && !(event instanceof TimerTriggerEvent) && !(event instanceof LockRegisterEvent)) {
  throw new IllegalArgumentException("Event not valid for coordinator: " + event.getClass());
}

boolean isCoordinatorEvent(OperatorEvent e) {
  return e instanceof CheckpointTriggerEvent || e instanceof TimerTriggerEvent || e instanceof LockRegisterEvent;
}

try { coordinator.sendOperatorEvent(event); } catch (IllegalArgumentException e) { LOG.warn("Rejected coordinator event {}", event.getClass(), e); }

When it happens

Trigger: An OperatorEvent of a type other than CheckpointTriggerEvent/TimerTriggerEvent/LockRegisterEvent arrives at the TriggerManagerCoordinator, e.g. a LockReleaseEvent sent to the coordinator instead of the operator, or an event from a mismatched operator version during job upgrade.

Common situations: Sending lock-release events to the wrong endpoint (coordinator vs operator); restoring a job from a savepoint produced by a different Iceberg version with a different event hierarchy; custom code firing events at the coordinator.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type:
• Unknown type for int field. Type name: ${className}
• Unknown type for long field. Type name: ${className}

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/cae130e7f94b2921. Report an issue: GitHub.