apache/flink · error · InvalidProgramException

The iteration {} has no next partial solution defined (is no

Error message

The iteration {} has no next partial solution defined (is not closed).

What it means

Thrown by CollectionExecutor.executeBulkIteration() when iteration.getNextPartialSolution() returns null. The next partial solution is the operator that produces the updated value for the next iteration step; if it is null, the iteration was never 'closed' — the developer forgot to call closeWith() to define the step function's output. This is an InvalidProgramException.

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/common/operators/CollectionExecutor.java:331

        } else {
            ctx = null;
        }

        return typedOp.executeOnCollections(inputData1, inputData2, ctx, executionConfig);
    }

    @SuppressWarnings("unchecked")
    private <T> List<T> executeBulkIteration(BulkIterationBase<?> iteration, JobInfo jobInfo)
            throws Exception {
        Operator<?> inputOp = iteration.getInput();
        if (inputOp == null) {
            throw new InvalidProgramException(
                    "The iteration "
                            + iteration.getName()
                            + " has no input (initial partial solution).");
        }
        if (iteration.getNextPartialSolution() == null) {
            throw new InvalidProgramException(
                    "The iteration "
                            + iteration.getName()
                            + " has no next partial solution defined (is not closed).");
        }

        List<T> inputData = (List<T>) execute(inputOp, jobInfo);

        // get the operators that are iterative
        Set<Operator<?>> dynamics = new LinkedHashSet<Operator<?>>();
        DynamicPathCollector dynCollector = new DynamicPathCollector(dynamics);
        iteration.getNextPartialSolution().accept(dynCollector);
        if (iteration.getTerminationCriterion() != null) {
            iteration.getTerminationCriterion().accept(dynCollector);
        }

        // register the aggregators
        for (AggregatorWithName<?> a : iteration.getAggregators().getAllRegisteredAggregators()) {
            aggregators.put(a.getName(), a.getAggregator());

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Call iter.closeWith(nextPartialSolution) to close the iteration and define the step function's output.
2. Verify the closeWith() call receives the correct DataSet that represents the result of one iteration step.
3. Review the iteration structure: iterate() → define step body → closeWith(stepResult) → use the returned DataSet.

Example fix

// before — iteration never closed
IterativeDataSet<Long> iter = initialDataSet.iterate(100);
DataSet<Long> step = iter.map(x -> x / 2);
// missing: DataSet<Long> result = iter.closeWith(step);
result.writeAsText(path);
// after
IterativeDataSet<Long> iter = initialDataSet.iterate(100);
DataSet<Long> step = iter.map(x -> x / 2);
DataSet<Long> result = iter.closeWith(step);
result.writeAsText(path);

// Ensure bulk iteration is closed
IterativeDataSet<Long> iter = initialDataSet.iterate(100);
DataSet<Long> step = iter.map(fn);
if (step == null) {
    throw new IllegalStateException("Step function result is null");
}
DataSet<Long> result = iter.closeWith(step); // required call

When it happens

Trigger: Creating an IterativeDataSet via dataSet.iterate(n) but never calling iterate.closeWith(stepResult). The iteration loop body is defined but never terminated, so getNextPartialSolution() remains null.

Common situations: A developer writes an iterative algorithm, defines the step function (the transformation applied each iteration), but forgets to close the loop with closeWith(). This is a common mistake when first learning the Flink iteration API. The code compiles but fails at execution time.

Related errors

• The iteration {} has no input (initial partial solution).
• The iteration {} has no solution set delta defined (is not c
• The iteration {} has no workset defined (is not closed).
• The delta iteration {} has no initial solution set.
• The delta iteration {} has no initial workset.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/6030c8d9fbcfe3e2. Report an issue: GitHub.