What causes "Suppressing exception in catch: {}" in apache/iceberg?

Inspect the 'Caused by' / suppressed exceptions in the logs alongside the original failure to find the abort-time root cause.

apache/iceberg · warning

Suppressing exception in catch: {}

Error message

Suppressing exception in catch: {}

What it means

RowDataRewriter.map(), when a commit fails, aborts the writer and then rethrows the original Throwable. If abort() itself throws, the abort exception is added as suppressed to the original and logged with this warning so it doesn't mask the real failure.

Source

Thrown at flink/v1.20/flink/src/main/java/org/apache/iceberg/flink/source/RowDataRewriter.java:154

    public List<DataFile> map(CombinedScanTask task) throws Exception {
      // Initialize the task writer.
      this.writer = taskWriterFactory.create();
      try (DataIterator<RowData> iterator =
          new DataIterator<>(rowDataReader, task, io, encryptionManager)) {
        while (iterator.hasNext()) {
          RowData rowData = iterator.next();
          writer.write(rowData);
        }
        return Lists.newArrayList(writer.dataFiles());
      } catch (Throwable originalThrowable) {
        try {
          LOG.error("Aborting commit for  (subTaskId {}, attemptId {})", subTaskId, attemptId);
          writer.abort();
          LOG.error("Aborted commit for  (subTaskId {}, attemptId {})", subTaskId, attemptId);
        } catch (Throwable inner) {
          if (originalThrowable != inner) {
            originalThrowable.addSuppressed(inner);
            LOG.warn("Suppressing exception in catch: {}", inner.getMessage(), inner);
          }
        }

        if (originalThrowable instanceof Exception) {
          throw originalThrowable;
        } else {
          throw new RuntimeException(originalThrowable);
        }
      }
    }
  }
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

Inspect the 'Caused by' / suppressed exceptions in the logs alongside the original failure to find the abort-time root cause.
Fix the original commit failure (the primary error is the one rethrown, not this suppressed one).
Verify storage/permissions so abort-time file cleanup succeeds.

Defensive patterns

Strategy: try-catch

Try / catch

try {
  writer.commit();
} catch (Throwable t) {
  // inspect t and its suppressed exceptions for the abort-time failure
  LOG.error("Commit failed with {} suppressed exceptions", t.getSuppressed().length, t);
  throw t;
}

Prevention

Always read the primary exception, not just the last one logged.
Ensure the FileIO has delete permissions so abort cleanup succeeds.
Monitor commit failure rates on the writer operator.

When it happens

Trigger: A writer commit throws; the subsequent writer.abort() in the catch block also throws (e.g. failure closing/cleaning up files), triggering the suppression log before the original error is rethrown.

Common situations: Failure during data-file cleanup after a commit error — e.g. FileIO errors deleting partially written files, or closing an already-broken writer.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/d735704b3f6220c8. Report an issue: GitHub.