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/* * gpuscan_add_scan_path - entrypoint of the set_rel_pathlist_hook */static voidgpuscan_add_scan_path(PlannerInfo *root,					  RelOptInfo *baserel,					  Index rtindex,					  RangeTblEntry *rte){
   	Path	   *pathnode;	List	   *dev_quals = NIL;	List	   *host_quals = NIL;	IndexOptInfo *indexOpt;	List	   *indexConds;	List	   *indexQuals;	cl_long		indexNBlocks;	ListCell   *lc;	/* call the secondary hook */	if (set_rel_pathlist_next)		set_rel_pathlist_next(root, baserel, rtindex, rte);	/* nothing to do, if either PG-Strom or GpuScan is not enabled */	if (!pgstrom_enabled || !enable_gpuscan)		return;	/* We already proved the relation empty, so nothing more to do */	if (is_dummy_rel(baserel))		return;	/* It is the role of built-in Append node */	if (rte->inh)		return;	/*	 * GpuScan can run on only base relations or foreign table managed	 * by arrow_fdw.	 */	if (rte->relkind == RELKIND_FOREIGN_TABLE)	{
   		if (!baseRelIsArrowFdw(baserel))			return;	}	else if (rte->relkind != RELKIND_RELATION &&			 rte->relkind != RELKIND_MATVIEW)		return;	/* Check whether the qualifier can run on GPU device */	foreach (lc, baserel->baserestrictinfo)	{
   		RestrictInfo   *rinfo = lfirst(lc);		if (pgstrom_device_expression(root, baserel, rinfo->clause))			dev_quals = lappend(dev_quals, rinfo);		else			host_quals = lappend(host_quals, rinfo);	}	if (dev_quals == NIL)		return;	/* Check availability of GpuScan+BRIN Index */	indexOpt = pgstrom_tryfind_brinindex(root, baserel,										 &indexConds,										 &indexQuals,										 &indexNBlocks);	/* add GpuScan path in single process */	pathnode = create_gpuscan_path(root, baserel,								   dev_quals,								   host_quals,								   0,								   indexOpt,								   indexConds,								   indexQuals,								   indexNBlocks);	add_path(baserel, pathnode);	/* If appropriate, consider parallel GpuScan */	if (baserel->consider_parallel && baserel->lateral_relids == NULL)	{
   		int		parallel_nworkers			= compute_parallel_worker(baserel,									  baserel->pages, -1.0,									  max_parallel_workers_per_gather);		/*		 * XXX - Do we need a something specific logic for GpuScan to adjust		 * parallel_workers.		 */		if (parallel_nworkers <= 0)			return;		/* add GpuScan path performing on parallel workers */		pathnode = create_gpuscan_path(root, baserel,									   dev_quals,									   host_quals,									   parallel_nworkers,									   indexOpt,									   indexConds,									   indexQuals,									   indexNBlocks);		add_partial_path(baserel, pathnode);	}}

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