createplan.c

关系型数据库 Postgresql 6.5.2

	}
	*nextsortop++ = InvalidOid;
	return result;
}

/*
 * set_noname_tlist_operators
 *	  Sets the key and keyop fields of resdom nodes in a target list.
 *
 *	  'tlist' is the target list
 *	  'pathkeys' is a list of N keys in the form((key1) (key2)...(keyn)),
 *				corresponding to vars in the target list that are to
 *				be sorted or hashed
 *	  'operators' is the corresponding list of N sort or hash operators
 *
 *	  Returns the modified-in-place target list.
 */
static List *
set_noname_tlist_operators(List *tlist, List *pathkeys, Oid *operators)
{
	int			keyno = 1;
	Node	   *pathkey;
	Resdom	   *resdom;
	List	   *i;

	foreach(i, pathkeys)
	{
		pathkey = lfirst((List *) lfirst(i));
		resdom = tlist_member((Var *) pathkey, tlist);
		if (resdom)
		{

			/*
			 * Order the resdom pathkey and replace the operator OID for
			 * each key with the regproc OID.
			 */
			resdom->reskey = keyno;
			resdom->reskeyop = get_opcode(operators[keyno - 1]);
		}
		keyno += 1;
	}
	return tlist;
}

/*
 * Copy cost and size info from a lower plan node to an inserted node.
 * This is not critical, since the decisions have already been made,
 * but it helps produce more reasonable-looking EXPLAIN output.
 */

static void
copy_costsize(Plan *dest, Plan *src)
{
	if (src)
	{
		dest->cost = src->cost;
		dest->plan_size = src->plan_size;
		dest->plan_width = src->plan_width;
	}
	else
	{
		dest->cost = 0;
		dest->plan_size = 0;
		dest->plan_width = 0;
	}
}


/*****************************************************************************
 *
 *
 *****************************************************************************/

/*
 * make_noname
 *	  Create plan nodes to sort or materialize relations into noname. The
 *	  result returned for a sort will look like (SEQSCAN(SORT(plan_node)))
 *	  or (SEQSCAN(MATERIAL(plan_node)))
 *
 *	  'tlist' is the target list of the scan to be sorted or hashed
 *	  'pathkeys' is the list of keys which the sort or hash will be done on
 *	  'operators' is the operators with which the sort or hash is to be done
 *		(a list of operator OIDs)
 *	  'plan_node' is the node which yields tuples for the sort
 *	  'nonametype' indicates which operation(sort or hash) to perform
 */
static Noname *
make_noname(List *tlist,
			List *pathkeys,
			Oid *operators,
			Plan *plan_node,
			int nonametype)
{
	List	   *noname_tlist;
	Noname	   *retval = NULL;

	/* Create a new target list for the noname, with keys set. */
	noname_tlist = set_noname_tlist_operators(new_unsorted_tlist(tlist),
											  pathkeys,
											  operators);
	switch (nonametype)
	{
		case NONAME_SORT:
			retval = (Noname *) make_seqscan(tlist,
											 NIL,
											 _NONAME_RELATION_ID_,
										 (Plan *) make_sort(noname_tlist,
													_NONAME_RELATION_ID_,
															plan_node,
													  length(pathkeys)));
			break;

		case NONAME_MATERIAL:
			retval = (Noname *) make_seqscan(tlist,
											 NIL,
											 _NONAME_RELATION_ID_,
									 (Plan *) make_material(noname_tlist,
													_NONAME_RELATION_ID_,
															plan_node,
													  length(pathkeys)));
			break;

		default:
			elog(ERROR, "make_noname: unknown noname type %d", nonametype);

	}
	return retval;
}


SeqScan    *
make_seqscan(List *qptlist,
			 List *qpqual,
			 Index scanrelid,
			 Plan *lefttree)
{
	SeqScan    *node = makeNode(SeqScan);
	Plan	   *plan = &node->plan;

	copy_costsize(plan, lefttree);
	plan->state = (EState *) NULL;
	plan->targetlist = qptlist;
	plan->qual = qpqual;
	plan->lefttree = lefttree;
	plan->righttree = NULL;
	node->scanrelid = scanrelid;
	node->scanstate = (CommonScanState *) NULL;

	return node;
}

static IndexScan *
make_indexscan(List *qptlist,
			   List *qpqual,
			   Index scanrelid,
			   List *indxid,
			   List *indxqual,
			   List *indxqualorig)
{
	IndexScan  *node = makeNode(IndexScan);
	Plan	   *plan = &node->scan.plan;

	copy_costsize(plan, NULL);
	plan->state = (EState *) NULL;
	plan->targetlist = qptlist;
	plan->qual = qpqual;
	plan->lefttree = NULL;
	plan->righttree = NULL;
	node->scan.scanrelid = scanrelid;
	node->indxid = indxid;
	node->indxqual = indxqual;
	node->indxqualorig = indxqualorig;
	node->scan.scanstate = (CommonScanState *) NULL;

	return node;
}


static NestLoop *
make_nestloop(List *qptlist,
			  List *qpqual,
			  Plan *lefttree,
			  Plan *righttree)
{
	NestLoop   *node = makeNode(NestLoop);
	Plan	   *plan = &node->join;

	/*
	 * this cost estimate is entirely bogus... hopefully it will be
	 * overwritten by caller.
	 */
	plan->cost = (lefttree ? lefttree->cost : 0) +
		(righttree ? righttree->cost : 0);
	plan->state = (EState *) NULL;
	plan->targetlist = qptlist;
	plan->qual = qpqual;
	plan->lefttree = lefttree;
	plan->righttree = righttree;
	node->nlstate = (NestLoopState *) NULL;

	return node;
}

static HashJoin *
make_hashjoin(List *tlist,
			  List *qpqual,
			  List *hashclauses,
			  Plan *lefttree,
			  Plan *righttree)
{
	HashJoin   *node = makeNode(HashJoin);
	Plan	   *plan = &node->join;

	/*
	 * this cost estimate is entirely bogus... hopefully it will be
	 * overwritten by caller.
	 */
	plan->cost = (lefttree ? lefttree->cost : 0) +
		(righttree ? righttree->cost : 0);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = qpqual;
	plan->lefttree = lefttree;
	plan->righttree = righttree;
	node->hashclauses = hashclauses;
	node->hashdone = false;

	return node;
}

static Hash *
make_hash(List *tlist, Var *hashkey, Plan *lefttree)
{
	Hash	   *node = makeNode(Hash);
	Plan	   *plan = &node->plan;

	copy_costsize(plan, lefttree);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = NULL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;
	node->hashkey = hashkey;

	return node;
}

static MergeJoin *
make_mergejoin(List *tlist,
			   List *qpqual,
			   List *mergeclauses,
			   Plan *righttree,
			   Plan *lefttree)
{
	MergeJoin  *node = makeNode(MergeJoin);
	Plan	   *plan = &node->join;

	/*
	 * this cost estimate is entirely bogus... hopefully it will be
	 * overwritten by caller.
	 */
	plan->cost = (lefttree ? lefttree->cost : 0) +
		(righttree ? righttree->cost : 0);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = qpqual;
	plan->lefttree = lefttree;
	plan->righttree = righttree;
	node->mergeclauses = mergeclauses;

	return node;
}

Sort *
make_sort(List *tlist, Oid nonameid, Plan *lefttree, int keycount)
{
	Sort	   *node = makeNode(Sort);
	Plan	   *plan = &node->plan;

	copy_costsize(plan, lefttree);
	plan->cost += cost_sort(NULL, plan->plan_size, plan->plan_width);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;
	node->nonameid = nonameid;
	node->keycount = keycount;

	return node;
}

static Material *
make_material(List *tlist,
			  Oid nonameid,
			  Plan *lefttree,
			  int keycount)
{
	Material   *node = makeNode(Material);
	Plan	   *plan = &node->plan;

	copy_costsize(plan, lefttree);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;
	node->nonameid = nonameid;
	node->keycount = keycount;

	return node;
}

Agg *
make_agg(List *tlist, Plan *lefttree)
{
	Agg		   *node = makeNode(Agg);

	copy_costsize(&node->plan, lefttree);
	node->plan.state = (EState *) NULL;
	node->plan.qual = NULL;
	node->plan.targetlist = tlist;
	node->plan.lefttree = lefttree;
	node->plan.righttree = (Plan *) NULL;
	node->aggs = NIL;

	return node;
}

Group *
make_group(List *tlist,
		   bool tuplePerGroup,
		   int ngrp,
		   AttrNumber *grpColIdx,
		   Sort *lefttree)
{
	Group	   *node = makeNode(Group);

	copy_costsize(&node->plan, (Plan *) lefttree);
	node->plan.state = (EState *) NULL;
	node->plan.qual = NULL;
	node->plan.targetlist = tlist;
	node->plan.lefttree = (Plan *) lefttree;
	node->plan.righttree = (Plan *) NULL;
	node->tuplePerGroup = tuplePerGroup;
	node->numCols = ngrp;
	node->grpColIdx = grpColIdx;

	return node;
}

/*
 *	A unique node always has a SORT node in the lefttree.
 *
 *	the uniqueAttr argument must be a null-terminated string,
 * either the name of the attribute to select unique on
 * or "*"
 */

Unique *
make_unique(List *tlist, Plan *lefttree, char *uniqueAttr)
{
	Unique	   *node = makeNode(Unique);
	Plan	   *plan = &node->plan;

	copy_costsize(plan, lefttree);
	plan->state = (EState *) NULL;
	plan->targetlist = tlist;
	plan->qual = NIL;
	plan->lefttree = lefttree;
	plan->righttree = NULL;
	node->nonameid = _NONAME_RELATION_ID_;
	node->keycount = 0;
	if (strcmp(uniqueAttr, "*") == 0)
		node->uniqueAttr = NULL;
	else
		node->uniqueAttr = pstrdup(uniqueAttr);
	return node;
}

#ifdef NOT_USED
List *
generate_fjoin(List *tlist)
{
	List		tlistP;
	List		newTlist = NIL;
	List		fjoinList = NIL;
	int			nIters = 0;

	/*
	 * Break the target list into elements with Iter nodes, and those
	 * without them.
	 */
	foreach(tlistP, tlist)
	{
		List		tlistElem;

		tlistElem = lfirst(tlistP);
		if (IsA(lsecond(tlistElem), Iter))
		{
			nIters++;
			fjoinList = lappend(fjoinList, tlistElem);
		}
		else
			newTlist = lappend(newTlist, tlistElem);
	}

	/*
	 * if we have an Iter node then we need to flatten.
	 */
	if (nIters > 0)
	{
		List	   *inner;
		List	   *tempList;
		Fjoin	   *fjoinNode;
		DatumPtr	results = (DatumPtr) palloc(nIters * sizeof(Datum));
		BoolPtr		alwaysDone = (BoolPtr) palloc(nIters * sizeof(bool));

		inner = lfirst(fjoinList);
		fjoinList = lnext(fjoinList);
		fjoinNode = (Fjoin) MakeFjoin(false,
									  nIters,
									  inner,
									  results,
									  alwaysDone);
		tempList = lcons(fjoinNode, fjoinList);
		newTlist = lappend(newTlist, tempList);
	}
	return newTlist;
	return tlist;				/* do nothing for now - ay 10/94 */
}

#endif