Function create_tablefunction_plan

src/backend/optimizer/plan/createplan.c:4540–4585

* create_tablefunction_plan * Returns a TableFunction plan for the base relation scanned by 'best_path' * with restriction clauses 'scan_clauses' and targetlist 'tlist'. */

 *	 with restriction clauses 'scan_clauses' and targetlist 'tlist'.
 */
static TableFunctionScan *
create_tablefunction_plan(PlannerInfo *root,
                          TableFunctionScanPath *best_path,
                          List *tlist,
                          List *scan_clauses)
{
    TableFunctionScan *tablefunc;
    RelOptInfo *rel = best_path->path.parent;
    Plan *subplan;
    Index scan_relid = rel->relid;
    RangeTblEntry *rte;
    RangeTblFunction *rtf;

    /* it should be a function base rel... */
    Assert(scan_relid > 0);
    rte = planner_rt_fetch(scan_relid, root);
    Assert(rel->rtekind == RTE_TABLEFUNCTION);
    Assert(list_length(rte->functions) == 1);
    rtf = linitial(rte->functions);

    /*
     * Recursively create Plan from Path for subquery.  Since we are entering
     * a different planner context (subroot), recurse to create_plan not
     * create_plan_recurse.
     */
    subplan = create_plan(rel->subroot, best_path->subpath, root->curSlice);

    /* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
    scan_clauses = extract_actual_clauses(scan_clauses, false);

    /* Replace any outer-relation variables with nestloop params */
    if (best_path->path.param_info) {
        scan_clauses = (List *)
                replace_nestloop_params(root, (Node *) scan_clauses);
        process_subquery_nestloop_params(root,
                                         rel->subplan_params);
    }

    /* Create the TableFunctionScan plan */
    tablefunc = make_tablefunction(tlist, scan_clauses, subplan, scan_relid, rtf);

    /* Cost is determined largely by the cost of the underlying subplan */
    copy_generic_path_info(&tablefunc->scan.plan, &best_path->path);

    return tablefunc;
}

/*
 * create_tablefuncscan_plan