apache/flink · error · IllegalArgumentException

An ordering must not be created with a NONE order.

Error message

An ordering must not be created with a NONE order.

What it means

Thrown by Ordering.appendOrdering when the Order parameter is Order.NONE. NONE is a sentinel meaning 'no ordering', which is semantically invalid when constructing an actual ordering requirement. The only valid values are Order.ASCENDING and Order.DESCENDING (and non-null).

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/common/operators/Ordering.java:73

    /**
     * Extends this ordering by appending an additional order requirement. If the index has been
     * previously appended then the unmodified Ordering is returned.
     *
     * @param index Field index of the appended order requirement.
     * @param type Type of the appended order requirement.
     * @param order Order of the appended order requirement.
     * @return This ordering with an additional appended order requirement.
     */
    public Ordering appendOrdering(
            Integer index, Class<? extends Comparable<?>> type, Order order) {
        if (index < 0) {
            throw new IllegalArgumentException("The key index must not be negative.");
        }
        if (order == null) {
            throw new NullPointerException();
        }
        if (order == Order.NONE) {
            throw new IllegalArgumentException(
                    "An ordering must not be created with a NONE order.");
        }

        if (!this.indexes.contains(index)) {
            this.indexes = this.indexes.addField(index);
            this.types.add(type);
            this.orders.add(order);
        }

        return this;
    }

    // --------------------------------------------------------------------------------------------

    public int getNumberOfFields() {
        return this.indexes.size();
    }

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Replace Order.NONE with Order.ASCENDING or Order.DESCENDING before calling appendOrdering.
2. Skip the appendOrdering call entirely if no ordering is needed for that field.
3. Validate the Order value: if (order == Order.NONE) order = Order.ASCENDING; or skip.

Example fix

// before
Order o = config.isDescending() ? Order.DESCENDING : Order.NONE;
ordering.appendOrdering(0, type, o);

// after
Order o = config.isDescending() ? Order.DESCENDING : Order.ASCENDING;
ordering.appendOrdering(0, type, o);

if (order == null || order == Order.NONE) {
    throw new IllegalArgumentException(
        "Order must be ASCENDING or DESCENDING, got: " + order);
}

static boolean isValidOrder(Order o) {
    return o == Order.ASCENDING || o == Order.DESCENDING;
}

When it happens

Trigger: Calling appendOrdering(index, type, Order.NONE) or new Ordering(0, type, Order.NONE). Defaulting an Order variable to NONE and passing it through.

Common situations: Using Order.NONE as a default placeholder and forgetting to replace it. Deserialising an order value that maps to NONE.

Related errors

• The key index must not be negative.
• The output size cannot be smaller than zero.
• The output cardinality cannot be smaller than zero.
• The size of produced records must be positive.
• The filter factor cannot be smaller than zero.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/1e43ec658de52818. Report an issue: GitHub.