apache/iceberg · error · IllegalArgumentException

Unsupported status:

Error message

Unsupported status: 

What it means

During assignSplits, the enumerator checks the SplitResult status from the split assigner; only an assignment status is supported, and any other status triggers this IllegalArgumentException. It indicates the assigner returned an unexpected internal state.

Source

Thrown at flink/v1.20/flink/src/main/java/org/apache/iceberg/flink/source/enumerator/AbstractIcebergEnumerator.java:156

      GetSplitResult getResult = assigner.getNext(hostname);
      if (getResult.status() == GetSplitResult.Status.AVAILABLE) {
        LOG.info("Assign split to subtask {}: {}", awaitingSubtask, getResult.split());
        enumeratorContext.assignSplit(getResult.split(), awaitingSubtask);
        awaitingReader.remove();
      } else if (getResult.status() == GetSplitResult.Status.CONSTRAINED) {
        getAvailableFutureIfNeeded();
        break;
      } else if (getResult.status() == GetSplitResult.Status.UNAVAILABLE) {
        if (shouldWaitForMoreSplits()) {
          getAvailableFutureIfNeeded();
          break;
        } else {
          LOG.info("No more splits available for subtask {}", awaitingSubtask);
          enumeratorContext.signalNoMoreSplits(awaitingSubtask);
          awaitingReader.remove();
        }
      } else {
        throw new IllegalArgumentException("Unsupported status: " + getResult.status());
      }
    }
  }

  /** return true if enumerator should wait for splits like in the continuous enumerator case */
  protected abstract boolean shouldWaitForMoreSplits();

  private synchronized void getAvailableFutureIfNeeded() {
    if (availableFuture.get() != null) {
      return;
    }

    CompletableFuture<Void> future =
        assigner
            .isAvailable()
            .thenAccept(
                ignore ->
                    // Must run assignSplits in coordinator thread

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Verify you are using the built-in Iceberg split assigner or that your custom assigner returns a supported SplitResult status.
2. Align connector versions across the cluster to avoid mixed assigner/enumerator behavior.
3. File/report with the SplitResult status value; this is an internal invariant violation, not user input error.

// Wrap job restart policy to capture enumerator failure cause
env.setRestartStrategy(RestartStrategies.failureRateRestart(3, Time.days(1), Time.minutes(1)));
// catch in a custom enumerator subclass if using a custom assigner:
try { assignSplits(); } catch (IllegalArgumentException e) { LOG.error("SplitResult status invalid", e); }

When it happens

Trigger: Called from handleSourceEvent, addSplitsBack, or a future callback when the SplitAssigner's getResult().status() is something other than the expected assignment status.

Common situations: A custom SplitAssigner implementation returning a non-standard status; internal bug or version mismatch in connector components.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• Received unknown event from subtask %d: %s
• Unexpected entry status: ${entry.status}
• Unsupported version:
• Source table %s contains one/all of the reserved property ke
• Cannot create the table with 'connector'='iceberg' table pro

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/2aad152779e53de5. Report an issue: GitHub.