@Override
    public boolean exceedsLimit(TaskModel task) {
        Optional<TaskDef> taskDefinition = task.getTaskDefinition();
        if (taskDefinition.isEmpty()) {
            return false;
        }
        int limit = taskDefinition.get().concurrencyLimit();
        if (limit <= 0) {
            return false;
        }

        try {
            recordCassandraDaoRequests(
                    "selectTaskDefLimit", task.getTaskType(), task.getWorkflowType());
            ResultSet resultSet =
                    session.execute(
                            selectTasksFromTaskDefLimitStatement.bind(task.getTaskDefName()));
            List<String> taskIds =
                    resultSet.all().stream()
                            .map(row -> row.getUUID(TASK_ID_KEY).toString())
                            .collect(Collectors.toList());
            long current = taskIds.size();

            if (!taskIds.contains(task.getTaskId()) && current >= limit) {
                LOGGER.info(
                        "Task execution count limited. task - {}:{}, limit: {}, current: {}",
                        task.getTaskId(),
                        task.getTaskDefName(),
                        limit,
                        current);
                Monitors.recordTaskConcurrentExecutionLimited(task.getTaskDefName(), limit);
                return true;
            }
        } catch (DriverException e) {
            Monitors.error(CLASS_NAME, "exceedsLimit");
            String errorMsg =
                    String.format(
                            "Failed to get in progress limit - %s:%s in workflow :%s",
                            task.getTaskDefName(), task.getTaskId(), task.getWorkflowInstanceId());
            LOGGER.error(errorMsg, e);
            throw new TransientException(errorMsg);
        }
        return false;
    }
This is a dummy implementation and this feature is not implemented for Cassandra backed
Conductor
cassandra-persistence/src/main/java/com/netflix/conductor/cassandra/dao/CassandraExecutionDAO.java