Reimplement the linked list data structure used throughout the backend.

In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.

The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.

9 files changed, 213 insertions, 215 deletions

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 217f06a6b2b..a4bc92b1c3b 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.114 2004/05/10 22:44:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.115 2004/05/26 04:41:21 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -102,11 +102,11 @@ make_one_rel(Query *root)
 static void
 set_base_rel_pathlists(Query *root)
 {
-	List	   *rellist;
+	ListCell	   *l;
 
-	foreach(rellist, root->base_rel_list)
+	foreach(l, root->base_rel_list)
 	{
-		RelOptInfo *rel = (RelOptInfo *) lfirst(rellist);
+		RelOptInfo *rel = (RelOptInfo *) lfirst(l);
 		Index		rti = rel->relid;
 		RangeTblEntry *rte;
 		List	   *inheritlist;
@@ -212,7 +212,7 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
 	int			parentRTindex = rti;
 	Oid			parentOID = rte->relid;
 	List	   *subpaths = NIL;
-	List	   *il;
+	ListCell   *il;
 
 	/*
 	 * XXX for now, can't handle inherited expansion of FOR UPDATE; can we
@@ -247,8 +247,8 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
 		Oid			childOID;
 		RelOptInfo *childrel;
 		List	   *reltlist;
-		List	   *parentvars;
-		List	   *childvars;
+		ListCell   *parentvars;
+		ListCell   *childvars;
 
 		childrte = rt_fetch(childRTindex, root->rtable);
 		childOID = childrte->relid;
@@ -300,7 +300,7 @@ set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
 		if (childrel->width > rel->width)
 			rel->width = childrel->width;
 
-		childvars = FastListValue(&childrel->reltargetlist);
+		childvars = list_head(FastListValue(&childrel->reltargetlist));
 		foreach(parentvars, FastListValue(&rel->reltargetlist))
 		{
 			Var		   *parentvar = (Var *) lfirst(parentvars);
@@ -366,11 +366,11 @@ set_subquery_pathlist(Query *root, RelOptInfo *rel,
 	{
 		/* OK to consider pushing down individual quals */
 		List	   *upperrestrictlist = NIL;
-		List	   *lst;
+		ListCell   *l;
 
-		foreach(lst, rel->baserestrictinfo)
+		foreach(l, rel->baserestrictinfo)
 		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(lst);
+			RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 			Node	   *clause = (Node *) rinfo->clause;
 
 			if (qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
@@ -434,7 +434,7 @@ make_fromexpr_rel(Query *root, FromExpr *from)
 {
 	int			levels_needed;
 	List	   *initial_rels = NIL;
-	List	   *jt;
+	ListCell   *jt;
 
 	/*
 	 * Count the number of child jointree nodes.  This is the depth of the
@@ -464,7 +464,7 @@ make_fromexpr_rel(Query *root, FromExpr *from)
 		/*
 		 * Single jointree node, so we're done.
 		 */
-		return (RelOptInfo *) lfirst(initial_rels);
+		return (RelOptInfo *) linitial(initial_rels);
 	}
 	else
 	{
@@ -516,7 +516,7 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels)
 
 	for (lev = 2; lev <= levels_needed; lev++)
 	{
-		List	   *x;
+		ListCell   *x;
 
 		/*
 		 * Determine all possible pairs of relations to be joined at this
@@ -548,7 +548,7 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels)
 		elog(ERROR, "failed to build any %d-way joins", levels_needed);
 	Assert(length(joinitems[levels_needed]) == 1);
 
-	rel = (RelOptInfo *) lfirst(joinitems[levels_needed]);
+	rel = (RelOptInfo *) linitial(joinitems[levels_needed]);
 
 	return rel;
 }
@@ -660,21 +660,22 @@ static void
 compare_tlist_datatypes(List *tlist, List *colTypes,
 						bool *differentTypes)
 {
-	List	   *i;
+	ListCell   *l;
+	ListCell   *colType = list_head(colTypes);
 
-	foreach(i, tlist)
+	foreach(l, tlist)
 	{
-		TargetEntry *tle = (TargetEntry *) lfirst(i);
+		TargetEntry *tle = (TargetEntry *) lfirst(l);
 
 		if (tle->resdom->resjunk)
 			continue;			/* ignore resjunk columns */
-		if (colTypes == NIL)
+		if (colType == NULL)
 			elog(ERROR, "wrong number of tlist entries");
-		if (tle->resdom->restype != lfirsto(colTypes))
+		if (tle->resdom->restype != lfirst_oid(colType))
 			differentTypes[tle->resdom->resno] = true;
-		colTypes = lnext(colTypes);
+		colType = lnext(colType);
 	}
-	if (colTypes != NIL)
+	if (colType != NULL)
 		elog(ERROR, "wrong number of tlist entries");
 }
 
@@ -712,7 +713,7 @@ qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual,
 {
 	bool		safe = true;
 	List	   *vars;
-	List	   *vl;
+	ListCell   *vl;
 	Bitmapset  *tested = NULL;
 
 	/* Refuse subselects (point 1) */
@@ -869,7 +870,7 @@ print_relids(Relids relids)
 static void
 print_restrictclauses(Query *root, List *clauses)
 {
-	List	   *l;
+	ListCell   *l;
 
 	foreach(l, clauses)
 	{
@@ -987,7 +988,7 @@ print_path(Query *root, Path *path, int indent)
 void
 debug_print_rel(Query *root, RelOptInfo *rel)
 {
-	List	   *l;
+	ListCell   *l;
 
 	printf("RELOPTINFO (");
 	print_relids(rel->relids);
diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c
index 96ce94c8fcb..c8b54bf223a 100644
--- a/src/backend/optimizer/path/clausesel.c
+++ b/src/backend/optimizer/path/clausesel.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.65 2004/05/10 22:44:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.66 2004/05/26 04:41:21 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -98,16 +98,16 @@ clauselist_selectivity(Query *root,
 {
 	Selectivity s1 = 1.0;
 	RangeQueryClause *rqlist = NULL;
-	List	   *clist;
+	ListCell   *l;
 
 	/*
 	 * Initial scan over clauses.  Anything that doesn't look like a
 	 * potential rangequery clause gets multiplied into s1 and forgotten.
 	 * Anything that does gets inserted into an rqlist entry.
 	 */
-	foreach(clist, clauses)
+	foreach(l, clauses)
 	{
-		Node	   *clause = (Node *) lfirst(clist);
+		Node	   *clause = (Node *) lfirst(l);
 		RestrictInfo *rinfo;
 		Selectivity s2;
 
@@ -143,7 +143,7 @@ clauselist_selectivity(Query *root,
 					(is_pseudo_constant_clause_relids(lsecond(expr->args),
 													  rinfo->right_relids) ||
 					 (varonleft = false,
-					  is_pseudo_constant_clause_relids(lfirst(expr->args),
+					  is_pseudo_constant_clause_relids(linitial(expr->args),
 													   rinfo->left_relids)));
 			}
 			else
@@ -151,7 +151,7 @@ clauselist_selectivity(Query *root,
 				ok = (NumRelids(clause) == 1) &&
 					(is_pseudo_constant_clause(lsecond(expr->args)) ||
 					 (varonleft = false,
-					  is_pseudo_constant_clause(lfirst(expr->args))));
+					  is_pseudo_constant_clause(linitial(expr->args))));
 			}
 
 			if (ok)
@@ -521,7 +521,7 @@ clause_selectivity(Query *root,
 		 *
 		 * XXX is this too conservative?
 		 */
-		List	   *arg;
+		ListCell   *arg;
 
 		s1 = 0.0;
 		foreach(arg, ((BoolExpr *) clause)->args)
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 94ce4446fa2..71b879b134a 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -49,7 +49,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.126 2004/04/06 18:46:03 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.127 2004/05/26 04:41:21 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -920,7 +920,7 @@ cost_mergejoin(MergePath *path, Query *root)
 	 */
 	if (mergeclauses)
 	{
-		firstclause = (RestrictInfo *) lfirst(mergeclauses);
+		firstclause = (RestrictInfo *) linitial(mergeclauses);
 		if (firstclause->left_mergescansel < 0)	/* not computed yet? */
 			mergejoinscansel(root, (Node *) firstclause->clause,
 							 &firstclause->left_mergescansel,
@@ -1069,7 +1069,7 @@ cost_hashjoin(HashPath *path, Query *root)
 	int			numbatches;
 	Selectivity innerbucketsize;
 	Selectivity joininfactor;
-	List	   *hcl;
+	ListCell   *hcl;
 
 	if (!enable_hashjoin)
 		startup_cost += disable_cost;
@@ -1267,7 +1267,7 @@ cost_hashjoin(HashPath *path, Query *root)
 void
 cost_qual_eval(QualCost *cost, List *quals)
 {
-	List	   *l;
+	ListCell   *l;
 
 	cost->startup = 0;
 	cost->per_tuple = 0;
@@ -1444,7 +1444,7 @@ static Selectivity
 approx_selectivity(Query *root, List *quals, JoinType jointype)
 {
 	Selectivity total = 1.0;
-	List	   *l;
+	ListCell   *l;
 
 	foreach(l, quals)
 	{
@@ -1699,7 +1699,7 @@ static void
 set_rel_width(Query *root, RelOptInfo *rel)
 {
 	int32		tuple_width = 0;
-	List	   *tllist;
+	ListCell   *tllist;
 
 	foreach(tllist, FastListValue(&rel->reltargetlist))
 	{
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 565e9018daa..7c72b540647 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.158 2004/03/27 00:24:28 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.159 2004/05/26 04:41:21 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -121,7 +121,7 @@ void
 create_index_paths(Query *root, RelOptInfo *rel)
 {
 	Relids		all_join_outerrelids = NULL;
-	List	   *ilist;
+	ListCell   *ilist;
 
 	foreach(ilist, rel->indexlist)
 	{
@@ -250,12 +250,12 @@ group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index)
 	{
 		Oid			curClass = classes[0];
 		FastList	clausegroup;
-		List	   *i;
+		ListCell   *l;
 
 		FastListInit(&clausegroup);
-		foreach(i, restrictinfo_list)
+		foreach(l, restrictinfo_list)
 		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
+			RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 
 			if (match_clause_to_indexcol(rel,
 										 index,
@@ -312,7 +312,7 @@ group_clauses_by_indexkey_for_join(Query *root,
 		Oid			curClass = classes[0];
 		FastList	clausegroup;
 		int			numsources;
-		List	   *i;
+		ListCell   *l;
 
 		FastListInit(&clausegroup);
 
@@ -324,9 +324,9 @@ group_clauses_by_indexkey_for_join(Query *root,
 		 * of a non-join clause if it appears after a join clause it is
 		 * redundant with.
 		 */
-		foreach(i, rel->baserestrictinfo)
+		foreach(l, rel->baserestrictinfo)
 		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
+			RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 
 			/* Can't use pushed-down clauses in outer join */
 			if (isouterjoin && rinfo->is_pushed_down)
@@ -344,11 +344,11 @@ group_clauses_by_indexkey_for_join(Query *root,
 		numsources = (FastListValue(&clausegroup) != NIL) ? 1 : 0;
 
 		/* Look for joinclauses that are usable with given outer_relids */
-		foreach(i, rel->joininfo)
+		foreach(l, rel->joininfo)
 		{
-			JoinInfo   *joininfo = (JoinInfo *) lfirst(i);
+			JoinInfo   *joininfo = (JoinInfo *) lfirst(l);
 			bool		jfoundhere = false;
-			List	   *j;
+			ListCell   *j;
 
 			if (!bms_is_subset(joininfo->unjoined_relids, outer_relids))
 				continue;
@@ -448,7 +448,7 @@ group_clauses_by_indexkey_for_or(RelOptInfo *rel,
 	{
 		Oid			curClass = classes[0];
 		FastList	clausegroup;
-		List	   *item;
+		ListCell   *item;
 
 		FastListInit(&clausegroup);
 
@@ -511,7 +511,6 @@ group_clauses_by_indexkey_for_or(RelOptInfo *rel,
 
 		indexcol++;
 		classes++;
-
 	} while (!DoneMatchingIndexKeys(classes));
 
 	/* if OR clause was not used then forget it, per comments above */
@@ -738,7 +737,7 @@ void
 check_partial_indexes(Query *root, RelOptInfo *rel)
 {
 	List	   *restrictinfo_list = rel->baserestrictinfo;
-	List	   *ilist;
+	ListCell   *ilist;
 
 	foreach(ilist, rel->indexlist)
 	{
@@ -772,7 +771,7 @@ check_partial_indexes(Query *root, RelOptInfo *rel)
 static bool
 pred_test(List *predicate_list, List *restrictinfo_list)
 {
-	List	   *pred;
+	ListCell   *pred;
 
 	/*
 	 * Note: if Postgres tried to optimize queries by forming equivalence
@@ -815,7 +814,7 @@ pred_test(List *predicate_list, List *restrictinfo_list)
 static bool
 pred_test_restrict_list(Expr *predicate, List *restrictinfo_list)
 {
-	List	   *item;
+	ListCell   *item;
 
 	foreach(item, restrictinfo_list)
 	{
@@ -839,8 +838,8 @@ pred_test_restrict_list(Expr *predicate, List *restrictinfo_list)
 static bool
 pred_test_recurse_clause(Expr *predicate, Node *clause)
 {
-	List	   *items,
-			   *item;
+	List	   *items;
+	ListCell   *item;
 
 	Assert(clause != NULL);
 	if (or_clause(clause))
@@ -883,8 +882,8 @@ pred_test_recurse_clause(Expr *predicate, Node *clause)
 static bool
 pred_test_recurse_pred(Expr *predicate, Node *clause)
 {
-	List	   *items,
-			   *item;
+	List	   *items;
+	ListCell   *item;
 
 	Assert(predicate != NULL);
 	if (or_clause((Node *) predicate))
@@ -1360,13 +1359,13 @@ static Relids
 indexable_outerrelids(RelOptInfo *rel, IndexOptInfo *index)
 {
 	Relids		outer_relids = NULL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, rel->joininfo)
+	foreach(l, rel->joininfo)
 	{
-		JoinInfo   *joininfo = (JoinInfo *) lfirst(i);
+		JoinInfo   *joininfo = (JoinInfo *) lfirst(l);
 		bool		match_found = false;
-		List	   *j;
+		ListCell   *j;
 
 		/*
 		 * Examine each joinclause in the JoinInfo node's list to see if
@@ -1433,8 +1432,8 @@ best_inner_indexscan(Query *root, RelOptInfo *rel,
 {
 	Path	   *cheapest = NULL;
 	bool		isouterjoin;
-	List	   *ilist;
-	List	   *jlist;
+	ListCell   *ilist;
+	ListCell   *jlist;
 	InnerIndexscanInfo *info;
 	MemoryContext oldcontext;
 
@@ -1538,7 +1537,7 @@ best_inner_indexscan(Query *root, RelOptInfo *rel,
 			}
 		}
 
-		if (jlist == NIL)		/* failed to find a match? */
+		if (jlist == NULL)		/* failed to find a match? */
 		{
 			List	   *clausegroups;
 
@@ -1676,7 +1675,7 @@ List *
 flatten_clausegroups_list(List *clausegroups)
 {
 	List	   *allclauses = NIL;
-	List	   *l;
+	ListCell   *l;
 
 	foreach(l, clausegroups)
 	{
@@ -1697,7 +1696,7 @@ Expr *
 make_expr_from_indexclauses(List *indexclauses)
 {
 	List	   *orclauses = NIL;
-	List	   *orlist;
+	ListCell   *orlist;
 
 	/* There's no such thing as an indexpath with zero scans */
 	Assert(indexclauses != NIL);
@@ -1715,7 +1714,7 @@ make_expr_from_indexclauses(List *indexclauses)
 	if (length(orclauses) > 1)
 		return make_orclause(orclauses);
 	else
-		return (Expr *) lfirst(orclauses);
+		return (Expr *) linitial(orclauses);
 }
 
 
@@ -1768,23 +1767,23 @@ match_index_to_operand(Node *operand,
 		 * could be avoided, at the cost of complicating all the callers
 		 * of this routine; doesn't seem worth it.)
 		 */
-		List	   *indexprs;
+		ListCell   *indexpr_item;
 		int			i;
 		Node	   *indexkey;
 
-		indexprs = index->indexprs;
+		indexpr_item = list_head(index->indexprs);
 		for (i = 0; i < indexcol; i++)
 		{
 			if (index->indexkeys[i] == 0)
 			{
-				if (indexprs == NIL)
+				if (indexpr_item == NULL)
 					elog(ERROR, "wrong number of index expressions");
-				indexprs = lnext(indexprs);
+				indexpr_item = lnext(indexpr_item);
 			}
 		}
-		if (indexprs == NIL)
+		if (indexpr_item == NULL)
 			elog(ERROR, "wrong number of index expressions");
-		indexkey = (Node *) lfirst(indexprs);
+		indexkey = (Node *) lfirst(indexpr_item);
 
 		/*
 		 * Does it match the operand?  Again, strip any relabeling.
@@ -2013,32 +2012,32 @@ List *
 expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
 {
 	FastList	resultquals;
+	ListCell   *clausegroup_item;
 	Oid		   *classes = index->classlist;
 
 	if (clausegroups == NIL)
 		return NIL;
 
 	FastListInit(&resultquals);
+	clausegroup_item = list_head(clausegroups);
 	do
 	{
 		Oid			curClass = classes[0];
-		List	   *i;
+		ListCell   *l;
 
-		foreach(i, (List *) lfirst(clausegroups))
+		foreach(l, (List *) lfirst(clausegroup_item))
 		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
+			RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 
 			FastConc(&resultquals,
 					 expand_indexqual_condition(rinfo, curClass));
 		}
 
-		clausegroups = lnext(clausegroups);
-
+		clausegroup_item = lnext(clausegroup_item);
 		classes++;
+	} while (clausegroup_item != NULL && !DoneMatchingIndexKeys(classes));
 
-	} while (clausegroups != NIL && !DoneMatchingIndexKeys(classes));
-
-	Assert(clausegroups == NIL);	/* else more groups than indexkeys... */
+	Assert(clausegroup_item == NULL);	/* else more groups than indexkeys... */
 
 	return FastListValue(&resultquals);
 }
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index ac6838d26e0..e854fe03b77 100644
--- a/src/backend/optimizer/path/joinpath.c
+++ b/src/backend/optimizer/path/joinpath.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.86 2004/04/06 18:46:03 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.87 2004/05/26 04:41:22 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -145,7 +145,7 @@ sort_inner_and_outer(Query *root,
 	Path	   *outer_path;
 	Path	   *inner_path;
 	List	   *all_pathkeys;
-	List	   *i;
+	ListCell   *l;
 
 	/*
 	 * If we are doing a right or full join, we must use *all* the
@@ -224,9 +224,9 @@ sort_inner_and_outer(Query *root,
 												  mergeclause_list,
 												  outerrel);
 
-	foreach(i, all_pathkeys)
+	foreach(l, all_pathkeys)
 	{
-		List	   *front_pathkey = lfirst(i);
+		List	   *front_pathkey = (List *) lfirst(l);
 		List	   *cur_pathkeys;
 		List	   *cur_mergeclauses;
 		List	   *outerkeys;
@@ -234,7 +234,7 @@ sort_inner_and_outer(Query *root,
 		List	   *merge_pathkeys;
 
 		/* Make a pathkey list with this guy first. */
-		if (i != all_pathkeys)
+		if (l != list_head(all_pathkeys))
 			cur_pathkeys = lcons(front_pathkey,
 								 lremove(front_pathkey,
 										 listCopy(all_pathkeys)));
@@ -338,7 +338,7 @@ match_unsorted_outer(Query *root,
 	Path	   *inner_cheapest_total = innerrel->cheapest_total_path;
 	Path	   *matpath = NULL;
 	Path	   *bestinnerjoin = NULL;
-	List	   *i;
+	ListCell   *l;
 
 	/*
 	 * Nestloop only supports inner, left, and IN joins.  Also, if we are
@@ -402,9 +402,9 @@ match_unsorted_outer(Query *root,
 											 outerrel->relids, jointype);
 	}
 
-	foreach(i, outerrel->pathlist)
+	foreach(l, outerrel->pathlist)
 	{
-		Path	   *outerpath = (Path *) lfirst(i);
+		Path	   *outerpath = (Path *) lfirst(l);
 		List	   *merge_pathkeys;
 		List	   *mergeclauses;
 		List	   *innersortkeys;
@@ -676,7 +676,7 @@ hash_inner_and_outer(Query *root,
 {
 	bool		isouterjoin;
 	List	   *hashclauses;
-	List	   *i;
+	ListCell   *l;
 
 	/*
 	 * Hashjoin only supports inner, left, and IN joins.
@@ -704,9 +704,9 @@ hash_inner_and_outer(Query *root,
 	 * are usable with this pair of sub-relations.
 	 */
 	hashclauses = NIL;
-	foreach(i, restrictlist)
+	foreach(l, restrictlist)
 	{
-		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(i);
+		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
 
 		if (!restrictinfo->can_join ||
 			restrictinfo->hashjoinoperator == InvalidOid)
@@ -803,11 +803,11 @@ select_mergejoin_clauses(RelOptInfo *joinrel,
 {
 	List	   *result_list = NIL;
 	bool		isouterjoin = IS_OUTER_JOIN(jointype);
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, restrictlist)
+	foreach(l, restrictlist)
 	{
-		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(i);
+		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
 
 		/*
 		 * If processing an outer join, only use its own join clauses in
diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 07caab48ac6..6debd825c11 100644
--- a/src/backend/optimizer/path/joinrels.c
+++ b/src/backend/optimizer/path/joinrels.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.67 2004/03/08 17:20:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.68 2004/05/26 04:41:22 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,10 +20,10 @@
 
 static List *make_rels_by_clause_joins(Query *root,
 						  RelOptInfo *old_rel,
-						  List *other_rels);
+						  ListCell *other_rels);
 static List *make_rels_by_clauseless_joins(Query *root,
 							  RelOptInfo *old_rel,
-							  List *other_rels);
+							  ListCell *other_rels);
 static bool is_inside_IN(Query *root, RelOptInfo *rel);
 
 
@@ -43,8 +43,8 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 {
 	List	   *result_rels = NIL;
 	List	   *new_rels;
-	List	   *nr;
-	List	   *r;
+	ListCell   *nr;
+	ListCell   *r;
 	int			k;
 
 	/*
@@ -64,13 +64,13 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 	foreach(r, joinrels[level - 1])
 	{
 		RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
-		List	   *other_rels;
+		ListCell   *other_rels;
 
 		if (level == 2)
 			other_rels = lnext(r);		/* only consider remaining initial
 										 * rels */
 		else
-			other_rels = joinrels[1];	/* consider all initial rels */
+			other_rels = list_head(joinrels[1]);	/* consider all initial rels */
 
 		if (old_rel->joininfo != NIL)
 		{
@@ -149,8 +149,8 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 		foreach(r, joinrels[k])
 		{
 			RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
-			List	   *other_rels;
-			List	   *r2;
+			ListCell   *other_rels;
+			ListCell   *r2;
 
 			if (old_rel->joininfo == NIL)
 				continue;		/* we ignore clauseless joins here */
@@ -158,15 +158,15 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 			if (k == other_level)
 				other_rels = lnext(r);	/* only consider remaining rels */
 			else
-				other_rels = joinrels[other_level];
+				other_rels = list_head(joinrels[other_level]);
 
-			foreach(r2, other_rels)
+			for_each_cell(r2, other_rels)
 			{
 				RelOptInfo *new_rel = (RelOptInfo *) lfirst(r2);
 
 				if (!bms_overlap(old_rel->relids, new_rel->relids))
 				{
-					List	   *i;
+					ListCell   *i;
 
 					/*
 					 * OK, we can build a rel of the right level from this
@@ -217,14 +217,14 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 		foreach(r, joinrels[level - 1])
 		{
 			RelOptInfo *old_rel = (RelOptInfo *) lfirst(r);
-			List	   *other_rels;
+			ListCell   *other_rels;
 
 			if (level == 2)
 				other_rels = lnext(r);	/* only consider remaining initial
 										 * rels */
 			else
-				other_rels = joinrels[1];		/* consider all initial
-												 * rels */
+				other_rels = list_head(joinrels[1]); /* consider all initial
+													  * rels */
 
 			new_rels = make_rels_by_clauseless_joins(root,
 													 old_rel,
@@ -271,7 +271,8 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
  *	  The join rel nodes are returned in a list.
  *
  * 'old_rel' is the relation entry for the relation to be joined
- * 'other_rels': other rels to be considered for joining
+ * 'other_rels': the first cell in a linked list containing the other
+ * rels to be considered for joining
  *
  * Currently, this is only used with initial rels in other_rels, but it
  * will work for joining to joinrels too, if the caller ensures there is no
@@ -282,10 +283,10 @@ make_rels_by_joins(Query *root, int level, List **joinrels)
 static List *
 make_rels_by_clause_joins(Query *root,
 						  RelOptInfo *old_rel,
-						  List *other_rels)
+						  ListCell *other_rels)
 {
 	List	   *result = NIL;
-	List	   *i,
+	ListCell   *i,
 			   *j;
 
 	foreach(i, old_rel->joininfo)
@@ -293,7 +294,7 @@ make_rels_by_clause_joins(Query *root,
 		JoinInfo   *joininfo = (JoinInfo *) lfirst(i);
 		Relids		unjoined_relids = joininfo->unjoined_relids;
 
-		foreach(j, other_rels)
+		for_each_cell(j, other_rels)
 		{
 			RelOptInfo *other_rel = (RelOptInfo *) lfirst(j);
 
@@ -324,7 +325,8 @@ make_rels_by_clause_joins(Query *root,
  *	  The join rel nodes are returned in a list.
  *
  * 'old_rel' is the relation entry for the relation to be joined
- * 'other_rels': other rels to be considered for joining
+ * 'other_rels': the first cell of a linked list containing the
+ * other rels to be considered for joining
  *
  * Currently, this is only used with initial rels in other_rels, but it would
  * work for joining to joinrels too.
@@ -332,12 +334,12 @@ make_rels_by_clause_joins(Query *root,
 static List *
 make_rels_by_clauseless_joins(Query *root,
 							  RelOptInfo *old_rel,
-							  List *other_rels)
+							  ListCell *other_rels)
 {
 	List	   *result = NIL;
-	List	   *i;
+	ListCell   *i;
 
-	foreach(i, other_rels)
+	for_each_cell(i, other_rels)
 	{
 		RelOptInfo *other_rel = (RelOptInfo *) lfirst(i);
 
@@ -370,11 +372,11 @@ make_rels_by_clauseless_joins(Query *root,
 static bool
 is_inside_IN(Query *root, RelOptInfo *rel)
 {
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, root->in_info_list)
+	foreach(l, root->in_info_list)
 	{
-		InClauseInfo *ininfo = (InClauseInfo *) lfirst(i);
+		InClauseInfo *ininfo = (InClauseInfo *) lfirst(l);
 
 		if (bms_is_subset(rel->relids, ininfo->righthand))
 			return true;
@@ -476,7 +478,7 @@ make_join_rel(Query *root, RelOptInfo *rel1, RelOptInfo *rel2,
 	 */
 	if (jointype == JOIN_INNER)
 	{
-		List	   *l;
+		ListCell   *l;
 
 		foreach(l, root->in_info_list)
 		{
diff --git a/src/backend/optimizer/path/orindxpath.c b/src/backend/optimizer/path/orindxpath.c
index 9722b69965d..cc160e7a46e 100644
--- a/src/backend/optimizer/path/orindxpath.c
+++ b/src/backend/optimizer/path/orindxpath.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.57 2004/01/05 23:39:54 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.58 2004/05/26 04:41:22 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -100,7 +100,7 @@ create_or_index_quals(Query *root, RelOptInfo *rel)
 	RestrictInfo *or_rinfo;
 	Selectivity or_selec,
 				orig_selec;
-	List	   *i;
+	ListCell   *i;
 
 	/*
 	 * We use the best_or_subclause_indexes() machinery to locate the
@@ -111,7 +111,7 @@ create_or_index_quals(Query *root, RelOptInfo *rel)
 	foreach(i, rel->joininfo)
 	{
 		JoinInfo   *joininfo = (JoinInfo *) lfirst(i);
-		List	   *j;
+		ListCell   *j;
 
 		foreach(j, joininfo->jinfo_restrictinfo)
 		{
@@ -150,7 +150,7 @@ create_or_index_quals(Query *root, RelOptInfo *rel)
 	newrinfos = make_restrictinfo_from_indexclauses(bestpath->indexclauses,
 													true, true);
 	Assert(length(newrinfos) == 1);
-	or_rinfo = (RestrictInfo *) lfirst(newrinfos);
+	or_rinfo = (RestrictInfo *) linitial(newrinfos);
 	rel->baserestrictinfo = nconc(rel->baserestrictinfo, newrinfos);
 
 	/*
@@ -190,15 +190,15 @@ create_or_index_quals(Query *root, RelOptInfo *rel)
 void
 create_or_index_paths(Query *root, RelOptInfo *rel)
 {
-	List	   *i;
+	ListCell   *l;
 
 	/*
 	 * Check each restriction clause to see if it is an OR clause, and if so,
 	 * try to make a path using it.
 	 */
-	foreach(i, rel->baserestrictinfo)
+	foreach(l, rel->baserestrictinfo)
 	{
-		RestrictInfo *rinfo = (RestrictInfo *) lfirst(i);
+		RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
 
 		if (restriction_is_or_clause(rinfo))
 		{
@@ -248,7 +248,7 @@ best_or_subclause_indexes(Query *root,
 	FastList	quals;
 	Cost		path_startup_cost;
 	Cost		path_total_cost;
-	List	   *slist;
+	ListCell   *slist;
 	IndexPath  *pathnode;
 
 	FastListInit(&infos);
@@ -283,7 +283,7 @@ best_or_subclause_indexes(Query *root,
 		 *
 		 * Total cost is sum of the per-scan costs.
 		 */
-		if (slist == subclauses)	/* first scan? */
+		if (slist == list_head(subclauses))	/* first scan? */
 			path_startup_cost = best_startup_cost;
 		path_total_cost += best_total_cost;
 	}
@@ -351,7 +351,7 @@ best_or_subclause_index(Query *root,
 						Cost *retTotalCost)		/* return value */
 {
 	bool		found = false;
-	List	   *ilist;
+	ListCell   *ilist;
 
 	foreach(ilist, rel->indexlist)
 	{
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index 65eb5cb8a65..af232bd0c98 100644
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.56 2004/04/07 17:42:28 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.57 2004/05/26 04:41:22 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -95,8 +95,8 @@ add_equijoined_keys(Query *root, RestrictInfo *restrictinfo)
 	PathKeyItem *item2 = makePathKeyItem(get_rightop(clause),
 										 restrictinfo->right_sortop,
 										 false);
-	List	   *newset,
-			   *cursetlink;
+	List	   *newset;
+	ListCell   *cursetlink;
 
 	/* We might see a clause X=X; don't make a single-element list from it */
 	if (equal(item1, item2))
@@ -122,10 +122,10 @@ add_equijoined_keys(Query *root, RestrictInfo *restrictinfo)
 	newset = NIL;
 
 	/* cannot use foreach here because of possible lremove */
-	cursetlink = root->equi_key_list;
+	cursetlink = list_head(root->equi_key_list);
 	while (cursetlink)
 	{
-		List	   *curset = lfirst(cursetlink);
+		List	   *curset = (List *) lfirst(cursetlink);
 		bool		item1here = member(item1, curset);
 		bool		item2here = member(item2, curset);
 
@@ -199,15 +199,15 @@ add_equijoined_keys(Query *root, RestrictInfo *restrictinfo)
 void
 generate_implied_equalities(Query *root)
 {
-	List	   *cursetlink;
+	ListCell   *cursetlink;
 
 	foreach(cursetlink, root->equi_key_list)
 	{
-		List	   *curset = lfirst(cursetlink);
+		List	   *curset = (List *) lfirst(cursetlink);
 		int			nitems = length(curset);
 		Relids	   *relids;
 		bool		have_consts;
-		List	   *ptr1;
+		ListCell   *ptr1;
 		int			i1;
 
 		/*
@@ -245,10 +245,10 @@ generate_implied_equalities(Query *root)
 		{
 			PathKeyItem *item1 = (PathKeyItem *) lfirst(ptr1);
 			bool		i1_is_variable = !bms_is_empty(relids[i1]);
-			List	   *ptr2;
+			ListCell   *ptr2;
 			int			i2 = i1 + 1;
 
-			foreach(ptr2, lnext(ptr1))
+			for_each_cell(ptr2, lnext(ptr1))
 			{
 				PathKeyItem *item2 = (PathKeyItem *) lfirst(ptr2);
 				bool		i2_is_variable = !bms_is_empty(relids[i2]);
@@ -294,14 +294,14 @@ generate_implied_equalities(Query *root)
 bool
 exprs_known_equal(Query *root, Node *item1, Node *item2)
 {
-	List	   *cursetlink;
+	ListCell   *cursetlink;
 
 	foreach(cursetlink, root->equi_key_list)
 	{
-		List	   *curset = lfirst(cursetlink);
+		List	   *curset = (List *) lfirst(cursetlink);
 		bool		item1member = false;
 		bool		item2member = false;
-		List	   *ptr;
+		ListCell   *ptr;
 
 		foreach(ptr, curset)
 		{
@@ -334,12 +334,12 @@ exprs_known_equal(Query *root, Node *item1, Node *item2)
 static List *
 make_canonical_pathkey(Query *root, PathKeyItem *item)
 {
-	List	   *cursetlink;
 	List	   *newset;
+	ListCell   *cursetlink;
 
 	foreach(cursetlink, root->equi_key_list)
 	{
-		List	   *curset = lfirst(cursetlink);
+		List	   *curset = (List *) lfirst(cursetlink);
 
 		if (member(item, curset))
 			return curset;
@@ -360,11 +360,11 @@ List *
 canonicalize_pathkeys(Query *root, List *pathkeys)
 {
 	List	   *new_pathkeys = NIL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, pathkeys)
+	foreach(l, pathkeys)
 	{
-		List	   *pathkey = (List *) lfirst(i);
+		List	   *pathkey = (List *) lfirst(l);
 		PathKeyItem *item;
 		List	   *cpathkey;
 
@@ -374,7 +374,7 @@ canonicalize_pathkeys(Query *root, List *pathkeys)
 		 * set by definition.
 		 */
 		Assert(pathkey != NIL);
-		item = (PathKeyItem *) lfirst(pathkey);
+		item = (PathKeyItem *) linitial(pathkey);
 		cpathkey = make_canonical_pathkey(root, item);
 
 		/*
@@ -402,11 +402,11 @@ canonicalize_pathkeys(Query *root, List *pathkeys)
 static int
 count_canonical_peers(Query *root, PathKeyItem *item)
 {
-	List	   *cursetlink;
+	ListCell   *cursetlink;
 
 	foreach(cursetlink, root->equi_key_list)
 	{
-		List	   *curset = lfirst(cursetlink);
+		List	   *curset = (List *) lfirst(cursetlink);
 
 		if (member(item, curset))
 			return length(curset) - 1;
@@ -430,15 +430,13 @@ count_canonical_peers(Query *root, PathKeyItem *item)
 PathKeysComparison
 compare_pathkeys(List *keys1, List *keys2)
 {
-	List	   *key1,
+	ListCell   *key1,
 			   *key2;
 
-	for (key1 = keys1, key2 = keys2;
-		 key1 != NIL && key2 != NIL;
-		 key1 = lnext(key1), key2 = lnext(key2))
+	forboth(key1, keys1, key2, keys2)
 	{
-		List	   *subkey1 = lfirst(key1);
-		List	   *subkey2 = lfirst(key2);
+		List	   *subkey1 = (List *) lfirst(key1);
+		List	   *subkey2 = (List *) lfirst(key2);
 
 		/*
 		 * XXX would like to check that we've been given canonicalized
@@ -465,9 +463,9 @@ compare_pathkeys(List *keys1, List *keys2)
 	 * the other list are not NIL --- no pathkey list should ever have a
 	 * NIL sublist.)
 	 */
-	if (key1 == NIL && key2 == NIL)
+	if (key1 == NULL && key2 == NULL)
 		return PATHKEYS_EQUAL;
-	if (key1 != NIL)
+	if (key1 != NULL)
 		return PATHKEYS_BETTER1;	/* key1 is longer */
 	return PATHKEYS_BETTER2;	/* key2 is longer */
 }
@@ -493,15 +491,13 @@ compare_pathkeys(List *keys1, List *keys2)
 PathKeysComparison
 compare_noncanonical_pathkeys(List *keys1, List *keys2)
 {
-	List	   *key1,
+	ListCell   *key1,
 			   *key2;
 
-	for (key1 = keys1, key2 = keys2;
-		 key1 != NIL && key2 != NIL;
-		 key1 = lnext(key1), key2 = lnext(key2))
+	forboth(key1, keys1, key2, keys2)
 	{
-		List	   *subkey1 = lfirst(key1);
-		List	   *subkey2 = lfirst(key2);
+		List	   *subkey1 = (List *) lfirst(key1);
+		List	   *subkey2 = (List *) lfirst(key2);
 
 		Assert(length(subkey1) == 1);
 		Assert(length(subkey2) == 1);
@@ -515,9 +511,9 @@ compare_noncanonical_pathkeys(List *keys1, List *keys2)
 	 * the other list are not NIL --- no pathkey list should ever have a
 	 * NIL sublist.)
 	 */
-	if (key1 == NIL && key2 == NIL)
+	if (key1 == NULL && key2 == NULL)
 		return PATHKEYS_EQUAL;
-	if (key1 != NIL)
+	if (key1 != NULL)
 		return PATHKEYS_BETTER1;	/* key1 is longer */
 	return PATHKEYS_BETTER2;	/* key2 is longer */
 }
@@ -573,11 +569,11 @@ get_cheapest_path_for_pathkeys(List *paths, List *pathkeys,
 							   CostSelector cost_criterion)
 {
 	Path	   *matched_path = NULL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, paths)
+	foreach(l, paths)
 	{
-		Path	   *path = (Path *) lfirst(i);
+		Path	   *path = (Path *) lfirst(l);
 
 		/*
 		 * Since cost comparison is a lot cheaper than pathkey comparison,
@@ -612,11 +608,11 @@ get_cheapest_fractional_path_for_pathkeys(List *paths,
 										  double fraction)
 {
 	Path	   *matched_path = NULL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, paths)
+	foreach(l, paths)
 	{
-		Path	   *path = (Path *) lfirst(i);
+		Path	   *path = (Path *) lfirst(l);
 
 		/*
 		 * Since cost comparison is a lot cheaper than pathkey comparison,
@@ -658,7 +654,7 @@ build_index_pathkeys(Query *root,
 	List	   *retval = NIL;
 	int		   *indexkeys = index->indexkeys;
 	Oid		   *ordering = index->ordering;
-	List	   *indexprs = index->indexprs;
+	ListCell   *indexprs_item = list_head(index->indexprs);
 
 	while (*ordering != InvalidOid)
 	{
@@ -683,10 +679,10 @@ build_index_pathkeys(Query *root,
 		else
 		{
 			/* expression --- assume we need not copy it */
-			if (indexprs == NIL)
+			if (indexprs_item == NULL)
 				elog(ERROR, "wrong number of index expressions");
-			indexkey = (Node *) lfirst(indexprs);
-			indexprs = lnext(indexprs);
+			indexkey = (Node *) lfirst(indexprs_item);
+			indexprs_item = lnext(indexprs_item);
 		}
 
 		/* OK, make a sublist for this sort key */
@@ -719,7 +715,7 @@ build_index_pathkeys(Query *root,
 static Var *
 find_indexkey_var(Query *root, RelOptInfo *rel, AttrNumber varattno)
 {
-	List	   *temp;
+	ListCell   *temp;
 	Index		relid;
 	Oid			reloid,
 				vartypeid;
@@ -758,12 +754,12 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery)
 	int			retvallen = 0;
 	int			outer_query_keys = length(root->query_pathkeys);
 	List	   *sub_tlist = rel->subplan->targetlist;
-	List	   *l;
+	ListCell   *i;
 
-	foreach(l, subquery->query_pathkeys)
+	foreach(i, subquery->query_pathkeys)
 	{
-		List	   *sub_pathkey = (List *) lfirst(l);
-		List	   *j;
+		List	   *sub_pathkey = (List *) lfirst(i);
+		ListCell   *j;
 		PathKeyItem *best_item = NULL;
 		int			best_score = 0;
 		List	   *cpathkey;
@@ -788,7 +784,7 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery)
 		{
 			PathKeyItem *sub_item = (PathKeyItem *) lfirst(j);
 			Node	   *sub_key = sub_item->key;
-			List	   *k;
+			ListCell   *k;
 
 			foreach(k, sub_tlist)
 			{
@@ -908,11 +904,11 @@ make_pathkeys_for_sortclauses(List *sortclauses,
 							  List *tlist)
 {
 	List	   *pathkeys = NIL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, sortclauses)
+	foreach(l, sortclauses)
 	{
-		SortClause *sortcl = (SortClause *) lfirst(i);
+		SortClause *sortcl = (SortClause *) lfirst(l);
 		Node	   *sortkey;
 		PathKeyItem *pathkey;
 
@@ -1000,21 +996,21 @@ find_mergeclauses_for_pathkeys(Query *root,
 							   List *restrictinfos)
 {
 	List	   *mergeclauses = NIL;
-	List	   *i;
+	ListCell   *i;
 
 	/* make sure we have pathkeys cached in the clauses */
 	foreach(i, restrictinfos)
 	{
-		RestrictInfo *restrictinfo = lfirst(i);
+		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(i);
 
 		cache_mergeclause_pathkeys(root, restrictinfo);
 	}
 
 	foreach(i, pathkeys)
 	{
-		List	   *pathkey = lfirst(i);
+		List	   *pathkey = (List *) lfirst(i);
 		List	   *matched_restrictinfos = NIL;
-		List	   *j;
+		ListCell   *j;
 
 		/*
 		 * We can match a pathkey against either left or right side of any
@@ -1037,7 +1033,7 @@ find_mergeclauses_for_pathkeys(Query *root,
 		 */
 		foreach(j, restrictinfos)
 		{
-			RestrictInfo *restrictinfo = lfirst(j);
+			RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(j);
 
 			/*
 			 * We can compare canonical pathkey sublists by simple pointer
@@ -1093,11 +1089,11 @@ make_pathkeys_for_mergeclauses(Query *root,
 							   RelOptInfo *rel)
 {
 	List	   *pathkeys = NIL;
-	List	   *i;
+	ListCell   *l;
 
-	foreach(i, mergeclauses)
+	foreach(l, mergeclauses)
 	{
-		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(i);
+		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(l);
 		List	   *pathkey;
 
 		cache_mergeclause_pathkeys(root, restrictinfo);
@@ -1160,18 +1156,18 @@ int
 pathkeys_useful_for_merging(Query *root, RelOptInfo *rel, List *pathkeys)
 {
 	int			useful = 0;
-	List	   *i;
+	ListCell   *i;
 
 	foreach(i, pathkeys)
 	{
-		List	   *pathkey = lfirst(i);
+		List	   *pathkey = (List *) lfirst(i);
 		bool		matched = false;
-		List	   *j;
+		ListCell   *j;
 
 		foreach(j, rel->joininfo)
 		{
 			JoinInfo   *joininfo = (JoinInfo *) lfirst(j);
-			List	   *k;
+			ListCell   *k;
 
 			foreach(k, joininfo->jinfo_restrictinfo)
 			{
diff --git a/src/backend/optimizer/path/tidpath.c b/src/backend/optimizer/path/tidpath.c
index 1baccc1b387..dcb6566db04 100644
--- a/src/backend/optimizer/path/tidpath.c
+++ b/src/backend/optimizer/path/tidpath.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/tidpath.c,v 1.18 2003/11/29 19:51:50 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/tidpath.c,v 1.19 2004/05/26 04:41:22 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,7 +33,7 @@ static List *TidqualFromExpr(int varno, Expr *expr);
 static bool
 isEvaluable(int varno, Node *node)
 {
-	List	   *lst;
+	ListCell   *l;
 	FuncExpr   *expr;
 
 	if (IsA(node, Const))
@@ -51,9 +51,9 @@ isEvaluable(int varno, Node *node)
 	if (!is_funcclause(node))
 		return false;
 	expr = (FuncExpr *) node;
-	foreach(lst, expr->args)
+	foreach(l, expr->args)
 	{
-		if (!isEvaluable(varno, lfirst(lst)))
+		if (!isEvaluable(varno, lfirst(l)))
 			return false;
 	}
 
@@ -81,7 +81,7 @@ TidequalClause(int varno, OpExpr *node)
 		return rnode;
 	if (length(node->args) != 2)
 		return rnode;
-	arg1 = lfirst(node->args);
+	arg1 = linitial(node->args);
 	arg2 = lsecond(node->args);
 
 	arg = NULL;
@@ -156,8 +156,8 @@ static List *
 TidqualFromExpr(int varno, Expr *expr)
 {
 	List	   *rlst = NIL,
-			   *lst,
 			   *frtn;
+	ListCell   *l;
 	Node	   *node = (Node *) expr,
 			   *rnode;
 
@@ -169,9 +169,9 @@ TidqualFromExpr(int varno, Expr *expr)
 	}
 	else if (and_clause(node))
 	{
-		foreach(lst, ((BoolExpr *) expr)->args)
+		foreach(l, ((BoolExpr *) expr)->args)
 		{
-			node = lfirst(lst);
+			node = (Node *) lfirst(l);
 			rlst = TidqualFromExpr(varno, (Expr *) node);
 			if (rlst)
 				break;
@@ -179,9 +179,9 @@ TidqualFromExpr(int varno, Expr *expr)
 	}
 	else if (or_clause(node))
 	{
-		foreach(lst, ((BoolExpr *) expr)->args)
+		foreach(l, ((BoolExpr *) expr)->args)
 		{
-			node = lfirst(lst);
+			node = (Node *) lfirst(l);
 			frtn = TidqualFromExpr(varno, (Expr *) node);
 			if (frtn)
 				rlst = nconc(rlst, frtn);
@@ -200,8 +200,8 @@ TidqualFromExpr(int varno, Expr *expr)
 static List *
 TidqualFromRestrictinfo(Relids relids, List *restrictinfo)
 {
-	List	   *lst,
-			   *rlst = NIL;
+	ListCell   *l;
+	List	   *rlst = NIL;
 	int			varno;
 	Node	   *node;
 	Expr	   *expr;
@@ -209,9 +209,9 @@ TidqualFromRestrictinfo(Relids relids, List *restrictinfo)
 	if (bms_membership(relids) != BMS_SINGLETON)
 		return NIL;
 	varno = bms_singleton_member(relids);
-	foreach(lst, restrictinfo)
+	foreach(l, restrictinfo)
 	{
-		node = lfirst(lst);
+		node = (Node *) lfirst(l);
 		if (!IsA(node, RestrictInfo))
 			continue;
 		expr = ((RestrictInfo *) node)->clause;