apache/iceberg · error · IllegalArgumentException

Invalid operator event type:

Error message

Invalid operator event type: 

What it means

LockRemoverCoordinator.handleEventFromOperator handles OperatorEvents sent from TriggerManager subtasks to the coordinator. It only accepts LockReleaseEvent; any other event type results in this IllegalArgumentException. The check happens inside a Tasks.foreach failure-handling wrapper, so the exception is wrapped with context (subtask, attempt number).

Source

Thrown at flink/v2.2/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/LockRemoverCoordinator.java:49

  LockRemoverCoordinator(String operatorName, Context context) {
    super(operatorName, context);
    LOG.info("Created LockRemoverCoordinator: {}", 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 LockReleaseEvent) {
            handleReleaseLock((LockReleaseEvent) 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. Ensure only LockReleaseEvent instances are sent to the LockRemover coordinator's event gateway.
2. Check that LockRegisterEvent is sent to TriggerManagerCoordinator, not LockRemoverCoordinator.
3. Restore the job with the same Iceberg version used to create the savepoint to avoid event type mismatch.

if (!(event instanceof LockReleaseEvent)) {
  LOG.warn("Skipping unexpected operator event: {}", event.getClass());
  return;
}

boolean isLockRelease(OperatorEvent e) { return e instanceof LockReleaseEvent; }

try {
  gateway.sendEventToCoordinator(new LockReleaseEvent(lockId));
} catch (IllegalArgumentException e) {
  LOG.error("Coordinator rejected event", e);
}

When it happens

Trigger: An OperatorEvent that is not a LockReleaseEvent is delivered to the LockRemover coordinator, e.g. a LockRegisterEvent sent to the wrong coordinator, or a custom/mismatched event from version-skewed operators during a job upgrade.

Common situations: Mixing operator versions during a savepoint restore across Iceberg versions, or wiring the wrong OperatorEventGateway so register events land on the remover coordinator.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type: <event.getClass().getCanonicalN

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/661f2faca7511734. Report an issue: GitHub.