pentaho/pentaho-kettle · error · KettleException

Unknown data type : type

Error message

Unknown data type : type

What it means

parseAttributeValue found a type prefix letter it does not support (expected S=String, D=Double, I=Long, B=Boolean) and throws KettleException "Unknown data type". The encoded attribute value was written with an unknown or corrupt type letter.

Solutions

1. Fix or delete the offending R_ELEMENT_ATTRIBUTE row so the value starts with a supported type letter (S:/D:/I:/B:)
2. Re-save the element via the metastore API to re-encode values
3. Ensure all PDI nodes sharing the repository run compatible versions
4. Pre-validate encoded values (empty or missing prefix) before parsing

Example fix

// before: trusting value
Object v = delegate.parseAttributeValue("42");
// after: guard the prefix
String value = "I:42";
if (value == null || value.isEmpty() || !"SDIB".contains(value.substring(0, 1))) {
  throw new IllegalArgumentException("Attribute value lacks valid type prefix: " + value);
}
Object v = delegate.parseAttributeValue(value);

boolean hasKnownTypePrefix(String encoded) { return encoded != null && !encoded.isEmpty() && "SDIB".indexOf(encoded.charAt(0)) >= 0; }

boolean isDecodableValue(String v) { return v != null && v.length() >= 2 && "SDIB".contains(v.substring(0,1)); }

try { Object v = delegate.parseAttributeValue(value); } catch (KettleException e) { v = defaultValue; logWarn("Unknown metastore value type: " + value, e); }

When it happens

Trigger: Reading a metastore attribute whose value string's first char is not one of S/D/I/B — e.g. empty value, manually edited row, or value written by a newer/older metastore encoder.

Common situations: Manual SQL edits to R_ELEMENT_ATTRIBUTE; empty value string missing its type prefix; version drift between PDI instances sharing one repository.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Can't encode object of class : className
• Unable to parse attribute from attribute row: attributeRow
• Can not create element type with id…
• Can not create element type with id
• Can't delete element type with name

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/983d53dd4b4c747b. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/repository/kdr/delegates/KettleDatabaseRepositoryMetaStoreDelegate.java:393

      return null;
    }
    String valueString = value.substring( 2 );
    char type = value.charAt( 0 );
    switch ( type ) {
      case 'S':
        return valueString;
      case 'T':
        return new SimpleTimestampFormat( ValueMetaBase.DEFAULT_TIMESTAMP_FORMAT_MASK ).parse( valueString );
      case 'D':
        return new SimpleDateFormat( ValueMetaBase.DEFAULT_DATE_FORMAT_MASK ).parse( valueString );
      case 'N':
        return Double.valueOf( valueString );
      case 'I':
        return Long.valueOf( valueString );
      case 'B':
        return "true".equalsIgnoreCase( valueString ) || "y".equalsIgnoreCase( valueString );
      default:
        throw new KettleException( "Unknown data type : " + type );
    }
  }

  public String encodeAttributeValue( Object object ) throws Exception {
    if ( object == null ) {
      return "";
    }
    if ( object instanceof String ) {
      return "S:" + object.toString();
    }
    if ( object instanceof Timestamp ) {
      return "T:" + new SimpleTimestampFormat(
        ValueMetaBase.DEFAULT_TIMESTAMP_FORMAT_MASK ).format( (Timestamp) object );
    }
    if ( object instanceof Date ) {
      return "D:" + new SimpleDateFormat( ValueMetaBase.DEFAULT_DATE_FORMAT_MASK ).format( (Date) object );
    }
    if ( object instanceof Double ) {

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