createplan.c

PostgreSQL7.4.6 for Linux

					if (!tlist_member(lfirst(k), tlist))
						break;
				}
				freeList(exprvars);
				if (!k)
					break;		/* found usable expression */
			}
			if (!j)
				elog(ERROR, "could not find pathkey item to sort");

			/*
			 * Do we need to insert a Result node?
			 *
			 * Currently, the only non-projection-capable plan types we can
			 * see here are Append and Unique.
			 */
			if (IsA(lefttree, Append) || IsA(lefttree, Unique))
			{
				tlist = copyObject(tlist);
				lefttree = (Plan *) make_result(tlist, NULL, lefttree);
			}

			/*
			 * Add resjunk entry to input's tlist
			 */
			resdom = makeResdom(length(tlist) + 1,
								exprType(pathkey->key),
								exprTypmod(pathkey->key),
								NULL,
								true);
			tlist = lappend(tlist,
							makeTargetEntry(resdom,
											(Expr *) pathkey->key));
			lefttree->targetlist = tlist;		/* just in case NIL before */
		}

		/*
		 * The column might already be selected as a sort key, if the
		 * pathkeys contain duplicate entries.	(This can happen in
		 * scenarios where multiple mergejoinable clauses mention the same
		 * var, for example.)  So enter it only once in the sort arrays.
		 */
		numsortkeys = add_sort_column(resdom->resno, pathkey->sortop,
								 numsortkeys, sortColIdx, sortOperators);
	}

	Assert(numsortkeys > 0);

	/* Give Sort node its own copy of the tlist (still necessary?) */
	sort_tlist = copyObject(tlist);

	return make_sort(root, sort_tlist, lefttree, numsortkeys,
					 sortColIdx, sortOperators);
}

/*
 * make_sort_from_sortclauses
 *	  Create sort plan to sort according to given sortclauses
 *
 *	  'tlist' is the targetlist
 *	  'lefttree' is the node which yields input tuples
 *	  'sortcls' is a list of SortClauses
 */
Sort *
make_sort_from_sortclauses(Query *root, List *tlist,
						   Plan *lefttree, List *sortcls)
{
	List	   *sort_tlist;
	List	   *i;
	int			numsortkeys;
	AttrNumber *sortColIdx;
	Oid		   *sortOperators;

	/* We will need at most length(sortcls) sort columns; possibly less */
	numsortkeys = length(sortcls);
	sortColIdx = (AttrNumber *) palloc(numsortkeys * sizeof(AttrNumber));
	sortOperators = (Oid *) palloc(numsortkeys * sizeof(Oid));

	numsortkeys = 0;

	foreach(i, sortcls)
	{
		SortClause *sortcl = (SortClause *) lfirst(i);
		TargetEntry *tle = get_sortgroupclause_tle(sortcl, tlist);
		Resdom	   *resdom = tle->resdom;

		/*
		 * Check for the possibility of duplicate order-by clauses --- the
		 * parser should have removed 'em, but no point in sorting
		 * redundantly.
		 */
		numsortkeys = add_sort_column(resdom->resno, sortcl->sortop,
								 numsortkeys, sortColIdx, sortOperators);
	}

	Assert(numsortkeys > 0);

	/* Give Sort node its own copy of the tlist (still necessary?) */
	sort_tlist = copyObject(tlist);

	return make_sort(root, sort_tlist, lefttree, numsortkeys,
					 sortColIdx, sortOperators);
}

/*
 * make_sort_from_groupcols
 *	  Create sort plan to sort based on grouping columns
 *
 * 'groupcls' is the list of GroupClauses
 * 'grpColIdx' gives the column numbers to use
 *
 * This might look like it could be merged with make_sort_from_sortclauses,
 * but presently we *must* use the grpColIdx[] array to locate sort columns,
 * because the child plan's tlist is not marked with ressortgroupref info
 * appropriate to the grouping node.  So, only the sortop is used from the
 * GroupClause entries.
 */
Sort *
make_sort_from_groupcols(Query *root,
						 List *groupcls,
						 AttrNumber *grpColIdx,
						 Plan *lefttree)
{
	List	   *sub_tlist = lefttree->targetlist;
	List	   *sort_tlist;
	int			grpno = 0;
	List	   *i;
	int			numsortkeys;
	AttrNumber *sortColIdx;
	Oid		   *sortOperators;

	/* We will need at most length(groupcls) sort columns; possibly less */
	numsortkeys = length(groupcls);
	sortColIdx = (AttrNumber *) palloc(numsortkeys * sizeof(AttrNumber));
	sortOperators = (Oid *) palloc(numsortkeys * sizeof(Oid));

	numsortkeys = 0;

	foreach(i, groupcls)
	{
		GroupClause *grpcl = (GroupClause *) lfirst(i);
		TargetEntry *tle = get_tle_by_resno(sub_tlist, grpColIdx[grpno]);
		Resdom	   *resdom = tle->resdom;

		/*
		 * Check for the possibility of duplicate group-by clauses --- the
		 * parser should have removed 'em, but no point in sorting
		 * redundantly.
		 */
		numsortkeys = add_sort_column(resdom->resno, grpcl->sortop,
								 numsortkeys, sortColIdx, sortOperators);
		grpno++;
	}

	Assert(numsortkeys > 0);

	/* Give Sort node its own copy of the tlist (still necessary?) */
	sort_tlist = copyObject(sub_tlist);

	return make_sort(root, sort_tlist, lefttree, numsortkeys,
					 sortColIdx, sortOperators);
}

Material *
make_material(List *tlist, Plan *lefttree)
{
	Material   *node = makeNode(Material);
	Plan	   *plan = &node->plan;

	/* cost should be inserted by caller */
	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;

	return node;
}

/*
 * materialize_finished_plan: stick a Material node atop a completed plan
 *
 * There are a couple of places where we want to attach a Material node
 * after completion of subquery_planner().	This currently requires hackery.
 * Since subquery_planner has already run SS_finalize_plan on the subplan
 * tree, we have to kluge up parameter lists for the Material node.
 * Possibly this could be fixed by postponing SS_finalize_plan processing
 * until setrefs.c is run?
 */
Plan *
materialize_finished_plan(Plan *subplan)
{
	Plan	   *matplan;
	Path		matpath;		/* dummy for result of cost_material */

	matplan = (Plan *) make_material(subplan->targetlist, subplan);

	/* Set cost data */
	cost_material(&matpath,
				  subplan->total_cost,
				  subplan->plan_rows,
				  subplan->plan_width);
	matplan->startup_cost = matpath.startup_cost;
	matplan->total_cost = matpath.total_cost;
	matplan->plan_rows = subplan->plan_rows;
	matplan->plan_width = subplan->plan_width;

	/* parameter kluge --- see comments above */
	matplan->extParam = bms_copy(subplan->extParam);
	matplan->allParam = bms_copy(subplan->allParam);

	return matplan;
}

Agg *
make_agg(Query *root, List *tlist, List *qual,
		 AggStrategy aggstrategy,
		 int numGroupCols, AttrNumber *grpColIdx,
		 long numGroups, int numAggs,
		 Plan *lefttree)
{
	Agg		   *node = makeNode(Agg);
	Plan	   *plan = &node->plan;
	Path		agg_path;		/* dummy for result of cost_agg */
	QualCost	qual_cost;

	node->aggstrategy = aggstrategy;
	node->numCols = numGroupCols;
	node->grpColIdx = grpColIdx;
	node->numGroups = numGroups;

	copy_plan_costsize(plan, lefttree); /* only care about copying size */
	cost_agg(&agg_path, root,
			 aggstrategy, numAggs,
			 numGroupCols, numGroups,
			 lefttree->startup_cost,
			 lefttree->total_cost,
			 lefttree->plan_rows);
	plan->startup_cost = agg_path.startup_cost;
	plan->total_cost = agg_path.total_cost;

	/*
	 * We will produce a single output tuple if not grouping, and a tuple
	 * per group otherwise.
	 */
	if (aggstrategy == AGG_PLAIN)
		plan->plan_rows = 1;
	else
		plan->plan_rows = numGroups;

	/*
	 * We also need to account for the cost of evaluation of the qual (ie,
	 * the HAVING clause) and the tlist.  Note that cost_qual_eval doesn't
	 * charge anything for Aggref nodes; this is okay since they are
	 * really comparable to Vars.
	 *
	 * See notes in grouping_planner about why this routine and make_group
	 * are the only ones in this file that worry about tlist eval cost.
	 */
	if (qual)
	{
		cost_qual_eval(&qual_cost, qual);
		plan->startup_cost += qual_cost.startup;
		plan->total_cost += qual_cost.startup;
		plan->total_cost += qual_cost.per_tuple * plan->plan_rows;
	}
	cost_qual_eval(&qual_cost, tlist);
	plan->startup_cost += qual_cost.startup;
	plan->total_cost += qual_cost.startup;
	plan->total_cost += qual_cost.per_tuple * plan->plan_rows;

	plan->qual = qual;
	plan->targetlist = tlist;
	plan->lefttree = lefttree;
	plan->righttree = (Plan *) NULL;

	return node;
}

Group *
make_group(Query *root,
		   List *tlist,
		   int numGroupCols,
		   AttrNumber *grpColIdx,
		   double numGroups,
		   Plan *lefttree)
{
	Group	   *node = makeNode(Group);
	Plan	   *plan = &node->plan;
	Path		group_path;		/* dummy for result of cost_group */
	QualCost	qual_cost;

	node->numCols = numGroupCols;
	node->grpColIdx = grpColIdx;

	copy_plan_costsize(plan, lefttree); /* only care about copying size */
	cost_group(&group_path, root,
			   numGroupCols, numGroups,
			   lefttree->startup_cost,
			   lefttree->total_cost,
			   lefttree->plan_rows);
	plan->startup_cost = group_path.startup_cost;
	plan->total_cost = group_path.total_cost;

	/* One output tuple per estimated result group */
	plan->plan_rows = numGroups;

	/*
	 * We also need to account for the cost of evaluation of the tlist.
	 *
	 * XXX this double-counts the cost of evaluation of any expressions used
	 * for grouping, since in reality those will have been evaluated at a
	 * lower plan level and will only be copied by the Group node. Worth
	 * fixing?
	 *
	 * See notes in grouping_planner about why this routine and make_agg are
	 * the only ones in this file that worry about tlist eval cost.
	 */
	cost_qual_eval(&qual_cost, tlist);
	plan->startup_cost += qual_cost.startup;
	plan->total_cost += qual_cost.startup;
	plan->total_cost += qual_cost.per_tuple * plan->plan_rows;

	plan->qual = NIL;
	plan->targetlist = tlist;
	plan->lefttree = lefttree;
	plan->righttree = (Plan *) NULL;

	return node;
}

/*
 * distinctList is a list of SortClauses, identifying the targetlist items
 * that should be considered by the Unique filter.
 */
Unique *
make_unique(List *tlist, Plan *lefttree, List *distinctList)
{
	Unique	   *node = makeNode(Unique);
	Plan	   *plan = &node->plan;
	int			numCols = length(distinctList);
	int			keyno = 0;
	AttrNumber *uniqColIdx;
	List	   *slitem;

	copy_plan_costsize(plan, lefttree);

	/*
	 * Charge one cpu_operator_cost per comparison per input tuple. We
	 * assume all columns get compared at most of the tuples.  (XXX
	 * probably this is an overestimate.)
	 */
	plan->total_cost += cpu_operator_cost * plan->plan_rows * numCols;

	/*
	 * plan->plan_rows is left as a copy of the input subplan's plan_rows;
	 * ie, we assume the filter removes nothing.  The caller must alter
	 * this if he has a better idea.
	 */

	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;

	/*
	 * convert SortClause list into array of attr indexes, as wanted by
	 * exec
	 */
	Assert(numCols > 0);
	uniqColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);

	foreach(slitem, distinctList)
	{
		SortClause *sortcl = (SortClause *) lfirst(slitem);
		TargetEntry *tle = get_sortgroupclause_tle(sortcl, tlist);

		uniqColIdx[keyno++] = tle->resdom->resno;
	}

	node->numCols = numCols;
	node->uniqColIdx = uniqColIdx;

	return node;
}

/*
 * distinctList is a list of SortClauses, identifying the targetlist items
 * that should be considered by the SetOp filter.
 */

SetOp *
make_setop(SetOpCmd cmd, List *tlist, Plan *lefttree,
		   List *distinctList, AttrNumber flagColIdx)
{
	SetOp	   *node = makeNode(SetOp);
	Plan	   *plan = &node->plan;
	int			numCols = length(distinctList);
	int			keyno = 0;
	AttrNumber *dupColIdx;
	List	   *slitem;

	copy_plan_costsize(plan, lefttree);

	/*
	 * Charge one cpu_operator_cost per comparison per input tuple. We
	 * assume all columns get compared at most of the tuples.
	 */
	plan->total_cost += cpu_operator_cost * plan->plan_rows * numCols;

	/*
	 * We make the unsupported assumption that there will be 10% as many
	 * tuples out as in.  Any way to do better?
	 */
	plan->plan_rows *= 0.1;
	if (plan->plan_rows < 1)
		plan->plan_rows = 1;

	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;

	/*
	 * convert SortClause list into array of attr indexes, as wanted by
	 * exec
	 */
	Assert(numCols > 0);
	dupColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);

	foreach(slitem, distinctList)
	{
		SortClause *sortcl = (SortClause *) lfirst(slitem);
		TargetEntry *tle = get_sortgroupclause_tle(sortcl, tlist);

		dupColIdx[keyno++] = tle->resdom->resno;
	}

	node->cmd = cmd;
	node->numCols = numCols;
	node->dupColIdx = dupColIdx;
	node->flagColIdx = flagColIdx;

	return node;
}

Limit *
make_limit(List *tlist, Plan *lefttree,
		   Node *limitOffset, Node *limitCount)
{
	Limit	   *node = makeNode(Limit);
	Plan	   *plan = &node->plan;

	copy_plan_costsize(plan, lefttree);

	/*
	 * If offset/count are constants, adjust the output rows count and
	 * costs accordingly.  This is only a cosmetic issue if we are at top
	 * level, but if we are building a subquery then it's important to
	 * report correct info to the outer planner.
	 */
	if (limitOffset && IsA(limitOffset, Const))
	{
		Const	   *limito = (Const *) limitOffset;
		int32		offset = DatumGetInt32(limito->con