Method getSubPlan

src/QueryPlan/QueryPlan.cpp:240–267

* Be careful, after we create a sub_plan, some nodes in the original plan have been deleted and deconstructed. * More precisely， nodes that moved to sub_plan are deleted. */

 * More precisely， nodes that moved to sub_plan are deleted.
 */
QueryPlan QueryPlan::getSubPlan(QueryPlan::Node * node_)
{
    QueryPlan sub_plan;

    std::stack<QueryPlan::Node *> plan_nodes;
    sub_plan.addRoot(Node{.step = node_->step, .children = node_->children, .id = node_->id});
    plan_nodes.push(sub_plan.getRoot());
    sub_plan.setResetStepId(reset_step_id);

    while (!plan_nodes.empty())
    {
        auto current = plan_nodes.top();
        plan_nodes.pop();

        std::vector<Node *> result_children;
        for (auto & child : current->children)
        {
            sub_plan.addNode(Node{.step = child->step, .children = child->children, .id = child->id});
            result_children.push_back(sub_plan.getLastNode());
            plan_nodes.push(sub_plan.getLastNode());
        }
        current->children.swap(result_children);
    }

    freshPlan();

    return sub_plan;
}

QueryPipelinePtr QueryPlan::buildQueryPipeline(
    const QueryPlanOptimizationSettings & optimization_settings, const BuildQueryPipelineSettings & build_pipeline_settings)