pentaho/pentaho-kettle · error · KettleDatabaseException

MondrianInputErrorOnlyTabular

MondrianInputErrorOnlyTabular

Error message

MondrianInputErrorOnlyTabular

What it means

MondrianHelper.createRectangularOutput() flattens an MDX result into rectangular headings/rows, which only works for a 2-axis (rows x columns) result. If the query's result has any number of axes other than 2, it throws KettleDatabaseException with the localized MondrianInputErrorOnlyTabular message. Used by MondrianInput's getFields and runtime output building.

Solutions

1. Rewrite the MDX so it produces exactly two axes: a columns axis and a rows axis (e.g. SELECT ... ON COLUMNS, ... ON ROWS).
2. Avoid DRILLTHROUGH / single-cell queries in the Mondrian Input step; use a JDBC/relational step for tabular data instead.
3. Log result.getAxes().length during development to confirm the shape.
4. Check Mondrian schema/cube definitions if axis count is unexpectedly different.

Example fix

// before: single axis query
mdx = "SELECT [Measures].[Sales] ON COLUMNS FROM Sales";
// after: two-axis (tabular) query
mdx = "SELECT [Measures].[Sales] ON COLUMNS, [Product].[Product].Members ON ROWS FROM Sales";

// Inspect the MDX result shape before flattening
Result result = olap4jConnection.createStatement().executeOlapQuery(mdx);
if (result.getAxes().size() != 2) {
  throw new IllegalStateException("MDX must return exactly 2 axes, got " + result.getAxes().size());
}

try {
  helper.createRectangularOutput();
} catch (KettleDatabaseException e) {
  logError("MDX result is not tabular (axes != 2): " + e.getMessage(), e);
}

When it happens

Trigger: Executing an MDX query whose result has axes.length != 2 — e.g. a query with 0 axes (scalar cell), 1 axis, or 3+ axes — then calling createRectangularOutput (directly or via getFields).

Common situations: MDX queries using DRILLTHROUGH or single-value queries; OLAP cubes configured so the Mondrian result returns one axis; users writing MDX meant for raw tabular output instead of a cross-tab.

Related errors

• Error setting catalog for MDX statement: ''
• Failed to add Cell Row:
• Failed to clear Cube
• Failed to process some row
• MondrianInputErrorUnhandledType

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/8254eba01144723c. Report an issue: GitHub.

Appendix: source

Thrown at plugins/mondrianinput/impl/src/main/java/org/pentaho/di/trans/steps/mondrianinput/MondrianHelper.java:193

        if ( ( log != null ) && ( log.isDebug() ) ) {
          log.logDebug( ignored.getMessage() );
        }
      }
      connection = null;
    }
  }

  /**
   * Outputs one row per tuple on the rows axis.
   *
   * @throws KettleDatabaseException
   *           in case some or other error occurs
   */
  public void createRectangularOutput() throws KettleDatabaseException {

    final Axis[] axes = result.getAxes();
    if ( axes.length != 2 ) {
      throw new KettleDatabaseException( BaseMessages.getString( PKG, "MondrianInputErrorOnlyTabular" ) );
    }
    headings = new ArrayList<>();
    rows = new ArrayList<>();

    final Axis rowsAxis = axes[1];
    final Axis columnsAxis = axes[0];

    int rowOrdinal = -1;
    int[] coords = { 0, 0 };
    for ( Position rowPos : rowsAxis.getPositions() ) {
      ++rowOrdinal;
      coords[1] = rowOrdinal;
      if ( rowOrdinal == 0 ) {
        // Generate headings on the first row. Note that if there are
        // zero rows, we don't have enough metadata to generate
        // headings.

        // First headings are for the members on the rows axis.

View on GitHub (pinned to f3058517a1)