Function create_tablefunction_path

src/backend/optimizer/util/pathnode.c:3269–3311

* create_tablefunction_path * Creates a path corresponding to a sequential scan of a table function, * returning the pathnode. * * NB: This is a GPDB specific thing, to support this syntax: * * SELECT * FROM multiset_5( TABLE( SELECT * from example) ) order by a, b; * * Despite the similar name, this is completely different from the upstream * create_tablefuncscan_path() function be

 * XMLTABLE and similar functions.
 */
TableFunctionScanPath *
create_tablefunction_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
						  List *pathkeys, Relids required_outer)
{
	TableFunctionScanPath *pathnode = makeNode(TableFunctionScanPath);

	/* Setup the basics of the TableFunction path */
	pathnode->path.pathtype = T_TableFunctionScan;
	pathnode->path.parent = rel;
	pathnode->path.pathtarget = rel->reltarget;
	pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
														  required_outer);
	pathnode->path.parallel_aware = false;
	pathnode->path.parallel_safe = rel->consider_parallel &&
		subpath->parallel_safe;
	pathnode->path.parallel_workers = subpath->parallel_workers;
	pathnode->path.pathkeys	   = NIL;		/* no way to specify output ordering */
	pathnode->subpath = subpath;

	pathnode->path.motionHazard = true;      /* better safe than sorry */
	pathnode->path.barrierHazard = true;      /* better safe than sorry */
	pathnode->path.rescannable  = false;     /* better safe than sorry */

	/*
	 * Inherit the locus of the input subquery's path.  This is necessary to handle the
	 * case of a General locus, e.g. if all the data has been concentrated to a
	 * single segment then the output will all be on that segment, otherwise the
	 * output must be declared as randomly distributed because we do not know
	 * what relationship, if any, there is between the input data and the output
	 * data.
	 */
	pathnode->path.locus = subpath->locus;

	/* Mark the output as random if the input is partitioned */
	if (CdbPathLocus_IsPartitioned(pathnode->path.locus))
		CdbPathLocus_MakeStrewn(&pathnode->path.locus,
								CdbPathLocus_NumSegments(pathnode->path.locus), 0); 
	pathnode->path.sameslice_relids = NULL;

	cost_tablefunction(pathnode, root, rel, pathnode->path.param_info);

	return pathnode;
}

/*
 * create_tablefuncscan_path