apache/seatunnel · error · UncheckedIOException

Failed to close equality delta writer

Error message

Failed to close equality delta writer

What it means

PartitionedDeltaWriter.close() iterates all wrapped per-partition RowDataDeltaWriters and closes them via a tries-run; if any writer's close throws an IOException it is rethrown as an UncheckedIOException. This indicates the underlying Iceberg write (e.g. closing a parquet/avro file or committing writes to the file IO) failed while finalizing the sink.

Source

Thrown at seatunnel-connectors-v2/connector-iceberg/src/main/java/org/apache/seatunnel/connectors/seatunnel/iceberg/sink/writer/PartitionedDeltaWriter.java:92

            PartitionKey copiedKey = partitionKey.copy();
            writer = new RowDataDeltaWriter(copiedKey);
            writers.put(copiedKey, writer);
        }

        return writer;
    }

    @Override
    public void close() {
        try {
            Tasks.foreach(writers.values())
                    .throwFailureWhenFinished()
                    .noRetry()
                    .run(RowDataDeltaWriter::close, IOException.class);

            writers.clear();
        } catch (IOException e) {
            throw new UncheckedIOException("Failed to close equality delta writer", e);
        }
    }
}

View on GitHub (pinned to cf67b549a7)

Solutions

1. Inspect the wrapped IOException (cause) for the real storage/IO error and fix storage connectivity, credentials, or disk space first
2. Retry the job; transient storage failures during close are often recoverable from the last checkpoint
3. Verify the warehouse/URI config (hdfs path, s3a endpoint) is reachable from all worker nodes
4. If reproducible with one file, check for corrupted in-progress write files in the target table location and clean stale files

// ensure target storage is reachable before submitting
// hdfs dfs -test -e <warehouse.path> || s3 ls <s3a.warehouse>

// engine-level: rely on checkpoint restart; at API level
try { deltaWriter.close(); } catch (UncheckedIOException e) { log.error("storage close failed", e.getCause()); throw e; }

When it happens

Trigger: Closing the delta writers at sink checkpoint/close time when one of the per-partition writers fails to flush or close its data files (disk full, HDFS/S3 IO failure, corrupted output stream).

Common situations: Underlying object store (S3/HDFS/OSS) outages or credential expiry mid-write; disk quota exhaustion on worker nodes; network interruptions between worker and storage during checkpoint close.

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

• WRITER_OPERATION_FAILED
• Cannot convert to BigDecimal:
• Cannot convert to boolean:
• Cannot convert to UUID:
• Cannot convert to binary:

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/f4de7928fd89094b. Report an issue: GitHub.