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CustomScan节点的targetlist、qual、custom_exprs是依赖于谁

• 答案：
  • 依赖于custom_scan_tlist

static voidset_customscan_references(PlannerInfo *root,						  CustomScan *cscan,						  int rtoffset){
   	ListCell   *lc;	/* Adjust scanrelid if it's valid */	if (cscan->scan.scanrelid > 0)		cscan->scan.scanrelid += rtoffset;	if (cscan->custom_scan_tlist != NIL || cscan->scan.scanrelid == 0)	{
   		/* Adjust tlist, qual, custom_exprs to reference custom scan tuple */		indexed_tlist *itlist = build_tlist_index(cscan->custom_scan_tlist);		cscan->scan.plan.targetlist = (List *)			fix_upper_expr(root,						   (Node *) cscan->scan.plan.targetlist,						   itlist,						   INDEX_VAR,						   rtoffset);		cscan->scan.plan.qual = (List *)			fix_upper_expr(root,						   (Node *) cscan->scan.plan.qual,						   itlist,						   INDEX_VAR,						   rtoffset);		cscan->custom_exprs = (List *)			fix_upper_expr(root,						   (Node *) cscan->custom_exprs,						   itlist,						   INDEX_VAR,						   rtoffset);		pfree(itlist);		/* custom_scan_tlist itself just needs fix_scan_list() adjustments */		cscan->custom_scan_tlist =			fix_scan_list(root, cscan->custom_scan_tlist, rtoffset);	}	else	{
   		/* Adjust tlist, qual, custom_exprs in the standard way */		cscan->scan.plan.targetlist =			fix_scan_list(root, cscan->scan.plan.targetlist, rtoffset);		cscan->scan.plan.qual =			fix_scan_list(root, cscan->scan.plan.qual, rtoffset);		cscan->custom_exprs =			fix_scan_list(root, cscan->custom_exprs, rtoffset);	}	/* Adjust child plan-nodes recursively, if needed */	foreach(lc, cscan->custom_plans)	{
   		lfirst(lc) = set_plan_refs(root, (Plan *) lfirst(lc), rtoffset);	}	/* Adjust custom_relids if needed */	if (rtoffset > 0)	{
   		Bitmapset  *tempset = NULL;		int			x = -1;		while ((x = bms_next_member(cscan->custom_relids, x)) >= 0)			tempset = bms_add_member(tempset, x + rtoffset);		cscan->custom_relids = tempset;	}}

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