flowable/flowable-engine · error · FlowableException

more than one result

Error message

more than one result

What it means

DmnDecisionServiceImpl.executeDecisionWithSingleResult runs a DMN decision and converts its result list into a single row. If the composed decision result contains more than one row it throws FlowableException("more than one result"), since a single-result API has no way to represent multiple matching output rows.

Source

Thrown at modules/flowable-dmn-engine/src/main/java/org/flowable/dmn/engine/impl/DmnDecisionServiceImpl.java:120

        }

        return singleDecisionResult;
    }

    @Override
    public Map<String, Object> executeDecisionWithSingleResult(ExecuteDecisionBuilder builder) {
        ExecuteDecisionContext executeDecisionContext = builder.buildExecuteDecisionContext();

        commandExecutor.execute(new ExecuteDecisionCmd(executeDecisionContext));

        Map<String, Object> singleDecisionResult = null;
        List<Map<String, Object>> decisionResult = composeDecisionResult(executeDecisionContext);

        finalizeDecisionExecutionAudit(executeDecisionContext);

        if (decisionResult != null && !decisionResult.isEmpty()) {
            if (decisionResult.size() > 1) {
                throw new FlowableException("more than one result");
            }
            singleDecisionResult = decisionResult.get(0);
        }

        return singleDecisionResult;
    }

    @Override
    public Map<String, Object> executeDecisionServiceWithSingleResult(ExecuteDecisionBuilder builder) {
        ExecuteDecisionContext executeDecisionContext = builder.buildExecuteDecisionContext();

        commandExecutor.execute(new ExecuteDecisionServiceCmd(executeDecisionContext));

        Map<String, Object> singleDecisionResult = new HashMap<>();
        Map<String, List<Map<String, Object>>> decisionResult = composeDecisionServiceResult(executeDecisionContext);

        finalizeDecisionExecutionAudit(executeDecisionContext);

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Adjust the decision model so exactly one row is produced per execution (exclusive conditions or FIRST hit policy).
2. Use the multi-result execution API instead and pick/aggregate the row you need.
3. Aggregate in the decision itself (e.g. return a sum or combined output) so the result is a single row.
4. Inspect input values with a test deployment to identify which rules overlap for the failing payload.

Example fix

// before
Map<String, Object> result = dmnService.executeDecisionWithSingleResult(ctx);
// after
List<Map<String, Object>> results = dmnService.executeDecision(ctx);
if (results == null || results.isEmpty()) {
    throw new IllegalStateException("decision returned no result");
}
Map<String, Object> result = results.get(0);

// Verify the decision cannot yield multiple rows, or use the multi-result API:
List<Map<String, Object>> results = dmnService.executeDecision(ctx);
if (results != null && results.size() > 1) {
    throw new IllegalStateException("expected single decision result, got " + results.size());
}

try {
    result = dmnService.executeDecisionWithSingleResult(ctx);
} catch (FlowableException e) {
    if ("more than one result".equals(e.getMessage())) {
        // retry with the multi-result API and aggregate/pick a row
    } else { throw e; }
}

When it happens

Trigger: Calling executeDecisionWithSingleResult for a decision expression/table that evaluates to multiple results — e.g. a decision table with overlapping rules producing several rows, or a collection-style decision returning multiple items — when the caller expected exactly one.

Common situations: Overlapping rule conditions in the DMN table (input ranges like x<10 and x>5); using COLLECT/multi-hit policies with a single-result invocation; business data changes causing previously-unique rules to both fire; forgotten aggregation (sum/count) upstream of the single-result call.

Related errors

• more than one result in decision:
• Cannot find case definition for id:
• DMN repository service is not available
• Decision has multiple results
• key is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/7d22d94e0ccf2132. Report an issue: GitHub.