pentaho/pentaho-kettle · error · KettleFileException

: Unable to write value timestamp data to output stream

Error message

 : Unable to write value timestamp data to output stream

What it means

Serialization failure in ValueMetaTimestamp.writeData(): writing the timestamp value to the output data stream failed (e.g. an I/O error or null stream while writing millis/nanos or a binary-string/indexed representation). Prefixed with this value's toString(); related ClassCastException and EOF paths are handled by adjacent catch blocks.

Solutions

1. Check the chained IOException cause (disk full, broken pipe, permission)
2. Verify free disk space and that the output file/stream is writable
3. Reopen the output stream and retry the batch
4. For network streams, add retry/restart logic on the step

Example fix

// before
DataOutputStream out = new DataOutputStream(new FileOutputStream(file));
meta.writeData(out, object); // fails if disk full / stream closed
// after
try (DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(file, true)))) {
  meta.writeData(out, object);
  out.flush();
} catch (KettleFileException e) {
  checkDiskSpaceAndRetry(file, object);
}

File f = new File(path);
if (f.getUsableSpace() < minRequiredBytes) throw new IOException("Insufficient disk space for row output");
if (!f.canWrite()) throw new IOException("Output file not writable: " + path);

try {
  meta.writeData(outputStream, object);
} catch (KettleFileException e) {
  if (e.getCause() instanceof IOException) {
    reopenStream();
    meta.writeData(outputStream, object); // retry once
  } else throw e;
}

When it happens

Trigger: Writing binary row data to a file/socket stream that is closed, full disk, broken pipe on a clustered slave connection, or permission loss mid-write.

Common situations: Disk full on large table-output-to-file jobs, network drops during clustered streaming, writing to removable media that disconnected.

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

• : Unknown storage type " + getStorageType()
• Cannot open control file
• Cannot open data file
• CubeInputMeta.Exception.ErrorOpeningOrReadingCubeFile
• CubeInputMeta.Exception.UnableToCloseCubeFile

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/d9e01d6cdc2d0970. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/row/value/ValueMetaTimestamp.java:614

            // at all.
            //
            writeBinaryString( outputStream, (byte[]) object );
            break;

          case STORAGE_TYPE_INDEXED:
            writeInteger( outputStream, (Integer) object ); // just an index
            break;

          default:
            throw new KettleFileException( toString() + " : Unknown storage type " + getStorageType() );
        }
      }
    } catch ( ClassCastException e ) {
      throw new RuntimeException( toString() + " : There was a data type error: the data type of "
        + object.getClass().getName() + " object [" + object + "] does not correspond to value meta ["
        + toStringMeta() + "]" );
    } catch ( IOException e ) {
      throw new KettleFileException( toString() + " : Unable to write value timestamp data to output stream", e );
    } catch ( KettleValueException e ) {
      throw new RuntimeException( toString() + " : There was a data type error: the data type of "
        + object.getClass().getName() + " object [" + object + "] does not correspond to value meta ["
        + toStringMeta() + "]" );
    }
  }

  @Override
  public Object readData( DataInputStream inputStream ) throws KettleFileException, KettleEOFException,
    SocketTimeoutException {
    try {
      // Is the value NULL?
      if ( inputStream.readBoolean() ) {
        return null; // done
      }

      switch ( storageType ) {
        case STORAGE_TYPE_NORMAL:

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