pentaho/pentaho-kettle · error · KettleFileException

: Unable to read value data from input stream

Error message

 : Unable to read value data from input stream

What it means

KettleFileException thrown by ValueMetaBase.readData wrapping an IOException (other than EOF/SocketTimeout, which map to KettleEOFException/rethrow): value data could not be read from the DataInputStream. The stream failed mid-read due to an I/O fault.

Solutions

  1. Inspect the wrapped cause (e.getCause()) for the root I/O error
  2. Validate stream/network health and re-establish the connection, then retry the transfer from a known checkpoint
  3. Check the source file for truncation/corruption and regenerate it

Example fix

// before
Object v = valueMeta.readData(inputStream); // network dropped mid-row
// after
try {
  Object v = valueMeta.readData(inputStream);
} catch (KettleFileException e) {
  reconnect(); inputStream = openStream(); // retry from checkpoint
}
Defensive patterns

Strategy: try-catch

Validate before calling

// Pre-flight the input stream:
if (inputStream == null) throw new IllegalStateException("Input stream is closed");
// available() > 0 on socket streams indicates data is present before a read attempt

Try / catch

try {
  Object v = valueMeta.readData(in);
} catch (KettleEOFException eof) {
  // clean end of stream: stop reading, no retry
} catch (KettleFileException e) {
  if (e.getCause() instanceof IOException) {
    LOG.error("Stream read failed for field " + valueMeta.getName() + ": " + e.getCause().getMessage());
    reconnectAndReopenStream(); // re-establish and resume from checkpoint
  } else { throw e; }
}

Prevention

When it happens

Trigger: readData() called on a DataInputStream from a socket or file that broke, was closed, or hit a device error while reading the row bytes.

Common situations: Cluster streaming where the peer node died or the network dropped; truncated/corrupt Kettle serialized file; concurrent closing of the input stream.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/028d1034dfba6188. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/row/value/ValueMetaBase.java:2841

              throw new KettleFileException( toString() + " : Unable to de-serialize data of type " + getType() );
          }

        case STORAGE_TYPE_BINARY_STRING:
          return readBinaryString( inputStream );

        case STORAGE_TYPE_INDEXED:
          return readSmallInteger( inputStream ); // just an index: 4-bytes should
          // be enough.

        default:
          throw new KettleFileException( toString() + " : Unknown storage type " + getStorageType() );
      }
    } catch ( EOFException e ) {
      throw new KettleEOFException( e );
    } catch ( SocketTimeoutException e ) {
      throw e;
    } catch ( IOException e ) {
      throw new KettleFileException( toString() + " : Unable to read value data from input stream", e );
    }
  }

  protected void writeString( DataOutputStream outputStream, String string ) throws IOException {
    // Write the length and then the bytes
    if ( string == null ) {
      outputStream.writeInt( -1 );
    } else {
      byte[] chars = string.getBytes( Const.XML_ENCODING );
      outputStream.writeInt( chars.length );
      outputStream.write( chars );
    }
  }

  protected void writeBinaryString( DataOutputStream outputStream, byte[] binaryString ) throws IOException {
    // Write the length and then the bytes
    if ( binaryString == null ) {
      outputStream.writeInt( -1 );

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