apache/seatunnel · error · SeaTunnelRuntimeException

FILE_SPLIT_SIZE_ILLEGAL

FILE_SPLIT_SIZE_ILLEGAL

Error message

file_split_size must be greater than 0 when enable_file_split=true, but got: %d

What it means

AccordingToSplitSizeSplitStrategy's constructor validates that file_split_size is positive when enable_file_split=true. A non-positive split size makes chunked reading meaningless, so FILE_SPLIT_SIZE_ILLEGAL is thrown.

Source

Thrown at seatunnel-connectors-v2/connector-file/connector-file-base/src/main/java/org/apache/seatunnel/connectors/seatunnel/file/source/split/AccordingToSplitSizeSplitStrategy.java:66

 * seek to locate the next delimiter around each split boundary.
 */
public class AccordingToSplitSizeSplitStrategy implements FileSplitStrategy, Closeable {

    private static final int BUFFER_SIZE = 64 * 1024;

    private final HadoopFileSystemProxy hadoopFileSystemProxy;
    private final long skipHeaderRowNumber;
    private final long splitSize;
    private final byte[] delimiterBytes;

    public AccordingToSplitSizeSplitStrategy(
            HadoopConf hadoopConf,
            String rowDelimiter,
            long skipHeaderRowNumber,
            String encodingName,
            long splitSize) {
        if (splitSize <= 0) {
            throw new SeaTunnelRuntimeException(
                    FileConnectorErrorCode.FILE_SPLIT_SIZE_ILLEGAL,
                    String.format(
                            "file_split_size must be greater than 0 when enable_file_split=true, but got: %d",
                            splitSize));
        }
        if (rowDelimiter == null || rowDelimiter.isEmpty()) {
            throw new SeaTunnelRuntimeException(
                    FileConnectorErrorCode.FILE_SPLIT_FAIL, "rowDelimiter must not be empty");
        }
        this.hadoopFileSystemProxy = new HadoopFileSystemProxy(hadoopConf);
        this.skipHeaderRowNumber = skipHeaderRowNumber;
        this.splitSize = splitSize;
        this.delimiterBytes = rowDelimiter.getBytes(Charset.forName(encodingName));
        if (delimiterBytes.length == 0) {
            throw new SeaTunnelRuntimeException(
                    FileConnectorErrorCode.FILE_SPLIT_FAIL,
                    "rowDelimiter must not be empty after encoding");
        }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Set file_split_size to a positive value (bytes), e.g. 104857600 for 100MB.
2. Remove file_split_size (and enable_file_split) to use default whole-file splits.
3. Check any variable/template substitution producing 0 or negative values.

Example fix

// before
enable_file_split = true
file_split_size = 0
// after
enable_file_split = true
file_split_size = 104857600

long splitSize = config.getLong("file_split_size");
if (config.getBoolean("enable_file_split") && splitSize <= 0) {
  throw new IllegalArgumentException("file_split_size must be > 0");
}

When it happens

Trigger: Constructing the split strategy with splitSize <= 0, which happens when file_split_size is configured as 0 or negative with enable_file_split=true.

Common situations: User sets file_split_size = 0 expecting 'unlimited'; unit confusion (bytes vs MB) leading to negative values after conversion.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• FILE_SPLIT_FAIL
• CONFIG_VALIDATION_FAILED
• CONFIG_VALIDATION_FAILED
• The read columns configuration will be filtered by the schem
• The SQL config must contain at least one source table

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/8e33077a4c79f6aa. Report an issue: GitHub.