apache/iceberg · error · IllegalArgumentException

Invalid operator event type:

Error message

Invalid operator event type: 

What it means

LockRemoverCoordinator.handleEventFromOperator accepts only LockReleaseEvent operator events from subtasks; any other event type throws IllegalArgumentException including the event's canonical class name. The coordinator wraps handling so failures are reported as a failed 'handling operator event' action.

Source

Thrown at flink/v2.1/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 all maintenance pipeline operators and the coordinator run the same Iceberg build (redeploy fully, don't mix versions across savepoint restore).
2. Inspect the class name in the message and remove/redirect the code path sending that event type to the lock coordinator.
3. Only send LockReleaseEvent (e.g. after a successful or failed maintenance cycle) to this coordinator.

if (event instanceof LockReleaseEvent release) {
  handleReleaseLock(release);
} else {
  LOG.warn("Ignoring non-release operator event: {}", event.getClass());
}

try {
  handleEventFromOperator(subtask, attempt, event);
} catch (IllegalArgumentException e) {
  LOG.error("Unexpected operator event {} - check for version-mixed deployment",
      e.getMessage());
}

When it happens

Trigger: An operator in the maintenance pipeline sends an OperatorEvent that is not a LockReleaseEvent to the coordinator — e.g. a mismatched event class after mixed-version deploy or a custom event sent to the wrong coordinator.

Common situations: Restoring a job from a savepoint made with a different Iceberg version whose event classes differ; custom extension code emitting extra operator events to the coordinator.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Invalid operator event type: ${eventClassCanonicalName}
• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type:
• Invalid operator event type:

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/2289d348c91c3a66. Report an issue: GitHub.