Improve the representation of FOR UPDATE/FOR SHARE so that we can

support both FOR UPDATE and FOR SHARE in one command, as well as both
NOWAIT and normal WAIT behavior.  The more general code is actually
simpler and cleaner.

src/backend/executor/execMain.c

@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.269 2006/03/05 15:58:25 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.270 2006/04/30 18:30:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -452,6 +452,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 	Relation	intoRelationDesc;
 	bool		do_select_into;
 	TupleDesc	tupType;
+	ListCell   *l;
 
 	/*
 	 * Do permissions checks.  It's sufficient to examine the query's top
@@ -486,7 +487,6 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 			 * parseTree->resultRelations identifies them all
 			 */
 			ResultRelInfo *resultRelInfo;
-			ListCell   *l;
 
 			numResultRelations = list_length(resultRelations);
 			resultRelInfos = (ResultRelInfo *)
@@ -549,26 +549,21 @@ InitPlan(QueryDesc *queryDesc, int eflags)
 	 * Have to lock relations selected FOR UPDATE/FOR SHARE
 	 */
 	estate->es_rowMarks = NIL;
-	estate->es_forUpdate = parseTree->forUpdate;
-	estate->es_rowNoWait = parseTree->rowNoWait;
-	if (parseTree->rowMarks != NIL)
+	foreach(l, parseTree->rowMarks)
 	{
-		ListCell   *l;
+		RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+		Oid			relid = getrelid(rc->rti, rangeTable);
+		Relation	relation;
+		ExecRowMark *erm;
 
-		foreach(l, parseTree->rowMarks)
-		{
-			Index		rti = lfirst_int(l);
-			Oid			relid = getrelid(rti, rangeTable);
-			Relation	relation;
-			ExecRowMark *erm;
-
-			relation = heap_open(relid, RowShareLock);
-			erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
-			erm->relation = relation;
-			erm->rti = rti;
-			snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
-			estate->es_rowMarks = lappend(estate->es_rowMarks, erm);
-		}
+		relation = heap_open(relid, RowShareLock);
+		erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
+		erm->relation = relation;
+		erm->rti = rc->rti;
+		erm->forUpdate = rc->forUpdate;
+		erm->noWait = rc->noWait;
+		snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rc->rti);
+		estate->es_rowMarks = lappend(estate->es_rowMarks, erm);
 	}
 
 	/*
@@ -1222,7 +1217,7 @@ lnext:	;
 
 					tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
 
-					if (estate->es_forUpdate)
+					if (erm->forUpdate)
 						lockmode = LockTupleExclusive;
 					else
 						lockmode = LockTupleShared;
@@ -1230,7 +1225,7 @@ lnext:	;
 					test = heap_lock_tuple(erm->relation, &tuple, &buffer,
 										   &update_ctid, &update_xmax,
 										   estate->es_snapshot->curcid,
-										   lockmode, estate->es_rowNoWait);
+										   lockmode, erm->noWait);
 					ReleaseBuffer(buffer);
 					switch (test)
 					{
@@ -2258,8 +2253,6 @@ EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
 		epqstate->es_param_exec_vals = (ParamExecData *)
 			palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
 	epqstate->es_rowMarks = estate->es_rowMarks;
-	epqstate->es_forUpdate = estate->es_forUpdate;
-	epqstate->es_rowNoWait = estate->es_rowNoWait;
 	epqstate->es_instrument = estate->es_instrument;
 	epqstate->es_select_into = estate->es_select_into;
 	epqstate->es_into_oids = estate->es_into_oids;

src/backend/executor/execUtils.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.133 2006/03/05 15:58:26 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.134 2006/04/30 18:30:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -204,8 +204,6 @@ CreateExecutorState(void)
 	estate->es_processed = 0;
 	estate->es_lastoid = InvalidOid;
 	estate->es_rowMarks = NIL;
-	estate->es_forUpdate = false;
-	estate->es_rowNoWait = false;
 
 	estate->es_instrument = false;
 	estate->es_select_into = false;

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.334 2006/04/22 01:25:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.335 2006/04/30 18:30:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1409,6 +1409,18 @@ _copyGroupClause(GroupClause *from)
 	return newnode;
 }
 
+static RowMarkClause *
+_copyRowMarkClause(RowMarkClause *from)
+{
+	RowMarkClause *newnode = makeNode(RowMarkClause);
+
+	COPY_SCALAR_FIELD(rti);
+	COPY_SCALAR_FIELD(forUpdate);
+	COPY_SCALAR_FIELD(noWait);
+
+	return newnode;
+}
+
 static A_Expr *
 _copyAExpr(A_Expr *from)
 {
@@ -1650,7 +1662,7 @@ _copyLockingClause(LockingClause *from)
 
 	COPY_NODE_FIELD(lockedRels);
 	COPY_SCALAR_FIELD(forUpdate);
-	COPY_SCALAR_FIELD(nowait);
+	COPY_SCALAR_FIELD(noWait);
 
 	return newnode;
 }
@@ -1673,9 +1685,6 @@ _copyQuery(Query *from)
 	COPY_SCALAR_FIELD(hasSubLinks);
 	COPY_NODE_FIELD(rtable);
 	COPY_NODE_FIELD(jointree);
-	COPY_NODE_FIELD(rowMarks);
-	COPY_SCALAR_FIELD(forUpdate);
-	COPY_SCALAR_FIELD(rowNoWait);
 	COPY_NODE_FIELD(targetList);
 	COPY_NODE_FIELD(groupClause);
 	COPY_NODE_FIELD(havingQual);
@@ -1683,6 +1692,7 @@ _copyQuery(Query *from)
 	COPY_NODE_FIELD(sortClause);
 	COPY_NODE_FIELD(limitOffset);
 	COPY_NODE_FIELD(limitCount);
+	COPY_NODE_FIELD(rowMarks);
 	COPY_NODE_FIELD(setOperations);
 	COPY_NODE_FIELD(resultRelations);
 
@@ -3284,6 +3294,9 @@ copyObject(void *from)
 		case T_GroupClause:
 			retval = _copyGroupClause(from);
 			break;
+		case T_RowMarkClause:
+			retval = _copyRowMarkClause(from);
+			break;
 		case T_FkConstraint:
 			retval = _copyFkConstraint(from);
 			break;

src/backend/nodes/equalfuncs.c

@@ -18,7 +18,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.270 2006/04/22 01:25:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.271 2006/04/30 18:30:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -665,9 +665,6 @@ _equalQuery(Query *a, Query *b)
 	COMPARE_SCALAR_FIELD(hasSubLinks);
 	COMPARE_NODE_FIELD(rtable);
 	COMPARE_NODE_FIELD(jointree);
-	COMPARE_NODE_FIELD(rowMarks);
-	COMPARE_SCALAR_FIELD(forUpdate);
-	COMPARE_SCALAR_FIELD(rowNoWait);
 	COMPARE_NODE_FIELD(targetList);
 	COMPARE_NODE_FIELD(groupClause);
 	COMPARE_NODE_FIELD(havingQual);
@@ -675,6 +672,7 @@ _equalQuery(Query *a, Query *b)
 	COMPARE_NODE_FIELD(sortClause);
 	COMPARE_NODE_FIELD(limitOffset);
 	COMPARE_NODE_FIELD(limitCount);
+	COMPARE_NODE_FIELD(rowMarks);
 	COMPARE_NODE_FIELD(setOperations);
 	COMPARE_NODE_FIELD(resultRelations);
 
@@ -1688,7 +1686,7 @@ _equalLockingClause(LockingClause *a, LockingClause *b)
 {
 	COMPARE_NODE_FIELD(lockedRels);
 	COMPARE_SCALAR_FIELD(forUpdate);
-	COMPARE_SCALAR_FIELD(nowait);
+	COMPARE_SCALAR_FIELD(noWait);
 
 	return true;
 }
@@ -1723,6 +1721,16 @@ _equalSortClause(SortClause *a, SortClause *b)
 	return true;
 }
 
+static bool
+_equalRowMarkClause(RowMarkClause *a, RowMarkClause *b)
+{
+	COMPARE_SCALAR_FIELD(rti);
+	COMPARE_SCALAR_FIELD(forUpdate);
+	COMPARE_SCALAR_FIELD(noWait);
+
+	return true;
+}
+
 static bool
 _equalFkConstraint(FkConstraint *a, FkConstraint *b)
 {
@@ -2297,6 +2305,9 @@ equal(void *a, void *b)
 			/* GroupClause is equivalent to SortClause */
 			retval = _equalSortClause(a, b);
 			break;
+		case T_RowMarkClause:
+			retval = _equalRowMarkClause(a, b);
+			break;
 		case T_FkConstraint:
 			retval = _equalFkConstraint(a, b);
 			break;

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.273 2006/04/22 01:25:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.274 2006/04/30 18:30:39 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1418,7 +1418,7 @@ _outLockingClause(StringInfo str, LockingClause *node)
 
 	WRITE_NODE_FIELD(lockedRels);
 	WRITE_BOOL_FIELD(forUpdate);
-	WRITE_BOOL_FIELD(nowait);
+	WRITE_BOOL_FIELD(noWait);
 }
 
 static void
@@ -1514,9 +1514,6 @@ _outQuery(StringInfo str, Query *node)
 	WRITE_BOOL_FIELD(hasSubLinks);
 	WRITE_NODE_FIELD(rtable);
 	WRITE_NODE_FIELD(jointree);
-	WRITE_NODE_FIELD(rowMarks);
-	WRITE_BOOL_FIELD(forUpdate);
-	WRITE_BOOL_FIELD(rowNoWait);
 	WRITE_NODE_FIELD(targetList);
 	WRITE_NODE_FIELD(groupClause);
 	WRITE_NODE_FIELD(havingQual);
@@ -1524,6 +1521,7 @@ _outQuery(StringInfo str, Query *node)
 	WRITE_NODE_FIELD(sortClause);
 	WRITE_NODE_FIELD(limitOffset);
 	WRITE_NODE_FIELD(limitCount);
+	WRITE_NODE_FIELD(rowMarks);
 	WRITE_NODE_FIELD(setOperations);
 	WRITE_NODE_FIELD(resultRelations);
 }
@@ -1546,6 +1544,16 @@ _outGroupClause(StringInfo str, GroupClause *node)
 	WRITE_OID_FIELD(sortop);
 }
 
+static void
+_outRowMarkClause(StringInfo str, RowMarkClause *node)
+{
+	WRITE_NODE_TYPE("ROWMARKCLAUSE");
+
+	WRITE_UINT_FIELD(rti);
+	WRITE_BOOL_FIELD(forUpdate);
+	WRITE_BOOL_FIELD(noWait);
+}
+
 static void
 _outSetOperationStmt(StringInfo str, SetOperationStmt *node)
 {
@@ -2113,6 +2121,9 @@ _outNode(StringInfo str, void *obj)
 			case T_GroupClause:
 				_outGroupClause(str, obj);
 				break;
+			case T_RowMarkClause:
+				_outRowMarkClause(str, obj);
+				break;
 			case T_SetOperationStmt:
 				_outSetOperationStmt(str, obj);
 				break;

src/backend/nodes/readfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.188 2006/04/22 01:25:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.189 2006/04/30 18:30:39 tgl Exp $
  *
  * NOTES
  *	  Path and Plan nodes do not have any readfuncs support, because we
@@ -147,9 +147,6 @@ _readQuery(void)
 	READ_BOOL_FIELD(hasSubLinks);
 	READ_NODE_FIELD(rtable);
 	READ_NODE_FIELD(jointree);
-	READ_NODE_FIELD(rowMarks);
-	READ_BOOL_FIELD(forUpdate);
-	READ_BOOL_FIELD(rowNoWait);
 	READ_NODE_FIELD(targetList);
 	READ_NODE_FIELD(groupClause);
 	READ_NODE_FIELD(havingQual);
@@ -157,6 +154,7 @@ _readQuery(void)
 	READ_NODE_FIELD(sortClause);
 	READ_NODE_FIELD(limitOffset);
 	READ_NODE_FIELD(limitCount);
+	READ_NODE_FIELD(rowMarks);
 	READ_NODE_FIELD(setOperations);
 	READ_NODE_FIELD(resultRelations);
 
@@ -219,6 +217,21 @@ _readGroupClause(void)
 	READ_DONE();
 }
 
+/*
+ * _readRowMarkClause
+ */
+static RowMarkClause *
+_readRowMarkClause(void)
+{
+	READ_LOCALS(RowMarkClause);
+
+	READ_UINT_FIELD(rti);
+	READ_BOOL_FIELD(forUpdate);
+	READ_BOOL_FIELD(noWait);
+
+	READ_DONE();
+}
+
 /*
  * _readSetOperationStmt
  */
@@ -934,6 +947,8 @@ parseNodeString(void)
 		return_value = _readSortClause();
 	else if (MATCH("GROUPCLAUSE", 11))
 		return_value = _readGroupClause();
+	else if (MATCH("ROWMARKCLAUSE", 13))
+		return_value = _readRowMarkClause();
 	else if (MATCH("SETOPERATIONSTMT", 16))
 		return_value = _readSetOperationStmt();
 	else if (MATCH("ALIAS", 5))

src/backend/optimizer/path/allpaths.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.144 2006/03/05 15:58:28 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.145 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -268,7 +268,7 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 	 * currently supposes that every rowMark relation is involved in every
 	 * row returned by the query.)
 	 */
-	if (list_member_int(root->parse->rowMarks, parentRTindex))
+	if (get_rowmark(root->parse, parentRTindex))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("SELECT FOR UPDATE/SHARE is not supported for inheritance queries")));

src/backend/optimizer/plan/createplan.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.209 2006/04/25 16:54:09 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.210 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -843,7 +843,7 @@ create_indexscan_plan(PlannerInfo *root,
 			if (best_path->indexinfo->indpred)
 			{
 				if (baserelid != root->parse->resultRelation &&
-					!list_member_int(root->parse->rowMarks, baserelid))
+					get_rowmark(root->parse, baserelid) == NULL)
 					if (predicate_implied_by(clausel,
 											 best_path->indexinfo->indpred))
 						continue;
@@ -962,7 +962,7 @@ create_bitmap_scan_plan(PlannerInfo *root,
 				if (ipath->indexinfo->indpred)
 				{
 					if (baserelid != root->parse->resultRelation &&
-						!list_member_int(root->parse->rowMarks, baserelid))
+						get_rowmark(root->parse, baserelid) == NULL)
 						if (predicate_implied_by(clausel,
 												 ipath->indexinfo->indpred))
 							continue;

src/backend/optimizer/prep/prepjointree.c

@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.37 2006/03/07 01:00:15 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.38 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -409,29 +409,9 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 
 	/*
 	 * Pull up any FOR UPDATE/SHARE markers, too.  (OffsetVarNodes
-	 * already adjusted the marker values, so just list_concat the
-	 * list.)
-	 *
-	 * Executor can't handle multiple FOR UPDATE/SHARE/NOWAIT flags,
-	 * so complain if they are valid but different
+	 * already adjusted the marker rtindexes, so just concat the lists.)
 	 */
-	if (parse->rowMarks && subquery->rowMarks)
-	{
-		if (parse->forUpdate != subquery->forUpdate)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot use both FOR UPDATE and FOR SHARE in one query")));
-		if (parse->rowNoWait != subquery->rowNoWait)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot use both wait and NOWAIT in one query")));
-	}
 	parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
-	if (subquery->rowMarks)
-	{
-		parse->forUpdate = subquery->forUpdate;
-		parse->rowNoWait = subquery->rowNoWait;
-	}
 
 	/*
 	 * We also have to fix the relid sets of any parent InClauseInfo

src/backend/optimizer/prep/preptlist.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.81 2006/04/05 22:11:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.82 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -116,7 +116,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
 		 * invalid.  This is also checked at parse time, but that's
 		 * insufficient because of rule substitution, query pullup, etc.
 		 */
-		CheckSelectLocking(parse, parse->forUpdate);
+		CheckSelectLocking(parse);
 
 		/*
 		 * Currently the executor only supports FOR UPDATE/SHARE at top level
@@ -128,19 +128,19 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
 
 		foreach(l, parse->rowMarks)
 		{
-			Index		rti = lfirst_int(l);
+			RowMarkClause *rc = (RowMarkClause *) lfirst(l);
 			Var		   *var;
 			char	   *resname;
 			TargetEntry *tle;
 
-			var = makeVar(rti,
+			var = makeVar(rc->rti,
 						  SelfItemPointerAttributeNumber,
 						  TIDOID,
 						  -1,
 						  0);
 
 			resname = (char *) palloc(32);
-			snprintf(resname, 32, "ctid%u", rti);
+			snprintf(resname, 32, "ctid%u", rc->rti);
 
 			tle = makeTargetEntry((Expr *) var,
 								  list_length(tlist) + 1,

src/backend/optimizer/prep/prepunion.c

@@ -22,7 +22,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.131 2006/03/05 15:58:31 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.132 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -816,7 +816,7 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
 	 */
 	if (rti == parse->resultRelation)
 		lockmode = RowExclusiveLock;
-	else if (list_member_int(parse->rowMarks, rti))
+	else if (get_rowmark(parse, rti))
 		lockmode = RowShareLock;
 	else
 		lockmode = AccessShareLock;

src/backend/parser/analyze.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.333 2006/04/22 01:25:59 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.334 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1805,6 +1805,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 {
 	Query	   *qry = makeNode(Query);
 	Node	   *qual;
+	ListCell   *l;
 
 	qry->commandType = CMD_SELECT;
 
@@ -1870,8 +1871,10 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
 		parseCheckAggregates(pstate, qry);
 
-	if (stmt->lockingClause)
-		transformLockingClause(qry, stmt->lockingClause);
+	foreach(l, stmt->lockingClause)
+	{
+		transformLockingClause(qry, (LockingClause *) lfirst(l));
+	}
 
 	return qry;
 }
@@ -1899,10 +1902,11 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	List	   *sortClause;
 	Node	   *limitOffset;
 	Node	   *limitCount;
-	LockingClause *lockingClause;
+	List	   *lockingClause;
 	Node	   *node;
 	ListCell   *left_tlist,
-			   *dtlist;
+			   *dtlist,
+			   *l;
 	List	   *targetvars,
 			   *targetnames,
 			   *sv_relnamespace,
@@ -1942,7 +1946,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	stmt->sortClause = NIL;
 	stmt->limitOffset = NULL;
 	stmt->limitCount = NULL;
-	stmt->lockingClause = NULL;
+	stmt->lockingClause = NIL;
 
 	/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
 	if (lockingClause)
@@ -2084,8 +2088,10 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
 		parseCheckAggregates(pstate, qry);
 
-	if (lockingClause)
-		transformLockingClause(qry, lockingClause);
+	foreach(l, lockingClause)
+	{
+		transformLockingClause(qry, (LockingClause *) lfirst(l));
+	}
 
 	return qry;
 }
@@ -2743,44 +2749,34 @@ transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt)
 
 /* exported so planner can check again after rewriting, query pullup, etc */
 void
-CheckSelectLocking(Query *qry, bool forUpdate)
+CheckSelectLocking(Query *qry)
 {
-	const char *operation;
-
-	if (forUpdate)
-		operation = "SELECT FOR UPDATE";
-	else
-		operation = "SELECT FOR SHARE";
-
 	if (qry->setOperations)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		/* translator: %s is a SQL command, like SELECT FOR UPDATE */
-		errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT", operation)));
+				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
 	if (qry->distinctClause != NIL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		/* translator: %s is a SQL command, like SELECT FOR UPDATE */
-			   errmsg("%s is not allowed with DISTINCT clause", operation)));
+				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with DISTINCT clause")));
 	if (qry->groupClause != NIL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		/* translator: %s is a SQL command, like SELECT FOR UPDATE */
-			   errmsg("%s is not allowed with GROUP BY clause", operation)));
+				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with GROUP BY clause")));
 	if (qry->havingQual != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		/* translator: %s is a SQL command, like SELECT FOR UPDATE */
-				 errmsg("%s is not allowed with HAVING clause", operation)));
+				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with HAVING clause")));
 	if (qry->hasAggs)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		/* translator: %s is a SQL command, like SELECT FOR UPDATE */
-		   errmsg("%s is not allowed with aggregate functions", operation)));
+				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with aggregate functions")));
 }
 
 /*
- * Convert FOR UPDATE/SHARE name list into rowMarks list of integer relids
+ * Transform a FOR UPDATE/SHARE clause
+ *
+ * This basically involves replacing names by integer relids.
  *
  * NB: if you need to change this, see also markQueryForLocking()
  * in rewriteHandler.c.
@@ -2789,35 +2785,18 @@ static void
 transformLockingClause(Query *qry, LockingClause *lc)
 {
 	List	   *lockedRels = lc->lockedRels;
-	List	   *rowMarks;
 	ListCell   *l;
 	ListCell   *rt;
 	Index		i;
 	LockingClause *allrels;
 
-	if (qry->rowMarks)
-	{
-		if (lc->forUpdate != qry->forUpdate)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("cannot use both FOR UPDATE and FOR SHARE in one query")));
-		if (lc->nowait != qry->rowNoWait)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot use both wait and NOWAIT in one query")));
-	}
-	qry->forUpdate = lc->forUpdate;
-	qry->rowNoWait = lc->nowait;
-
-	CheckSelectLocking(qry, lc->forUpdate);
+	CheckSelectLocking(qry);
 
 	/* make a clause we can pass down to subqueries to select all rels */
 	allrels = makeNode(LockingClause);
 	allrels->lockedRels = NIL;	/* indicates all rels */
 	allrels->forUpdate = lc->forUpdate;
-	allrels->nowait = lc->nowait;
-
-	rowMarks = qry->rowMarks;
+	allrels->noWait = lc->noWait;
 
 	if (lockedRels == NIL)
 	{
@@ -2831,8 +2810,7 @@ transformLockingClause(Query *qry, LockingClause *lc)
 			switch (rte->rtekind)
 			{
 				case RTE_RELATION:
-					/* use list_append_unique to avoid duplicates */
-					rowMarks = list_append_unique_int(rowMarks, i);
+					applyLockingClause(qry, i, lc->forUpdate, lc->noWait);
 					rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
 					break;
 				case RTE_SUBQUERY:
@@ -2867,8 +2845,8 @@ transformLockingClause(Query *qry, LockingClause *lc)
 					switch (rte->rtekind)
 					{
 						case RTE_RELATION:
-							/* use list_append_unique to avoid duplicates */
-							rowMarks = list_append_unique_int(rowMarks, i);
+							applyLockingClause(qry, i,
+											   lc->forUpdate, lc->noWait);
 							rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
 							break;
 						case RTE_SUBQUERY:
@@ -2909,8 +2887,41 @@ transformLockingClause(Query *qry, LockingClause *lc)
 								relname)));
 		}
 	}
+}
 
-	qry->rowMarks = rowMarks;
+/*
+ * Record locking info for a single rangetable item
+ */
+void
+applyLockingClause(Query *qry, Index rtindex, bool forUpdate, bool noWait)
+{
+	RowMarkClause *rc;
+
+	/* Check for pre-existing entry for same rtindex */
+	if ((rc = get_rowmark(qry, rtindex)) != NULL)
+	{
+		/*
+		 * If the same RTE is specified both FOR UPDATE and FOR SHARE,
+		 * treat it as FOR UPDATE.  (Reasonable, since you can't take
+		 * both a shared and exclusive lock at the same time; it'll
+		 * end up being exclusive anyway.)
+		 *
+		 * We also consider that NOWAIT wins if it's specified both ways.
+		 * This is a bit more debatable but raising an error doesn't
+		 * seem helpful.  (Consider for instance SELECT FOR UPDATE NOWAIT
+		 * from a view that internally contains a plain FOR UPDATE spec.)
+		 */
+		rc->forUpdate |= forUpdate;
+		rc->noWait |= noWait;
+		return;
+	}
+
+	/* Make a new RowMarkClause */
+	rc = makeNode(RowMarkClause);
+	rc->rti = rtindex;
+	rc->forUpdate = forUpdate;
+	rc->noWait = noWait;
+	qry->rowMarks = lappend(qry->rowMarks, rc);
 }
 
 

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.543 2006/04/27 00:33:45 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.544 2006/04/30 18:30:39 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -96,7 +96,7 @@ static List *check_func_name(List *names);
 static List *extractArgTypes(List *parameters);
 static SelectStmt *findLeftmostSelect(SelectStmt *node);
 static void insertSelectOptions(SelectStmt *stmt,
-								List *sortClause, Node *lockingClause,
+								List *sortClause, List *lockingClause,
 								Node *limitOffset, Node *limitCount);
 static Node *makeSetOp(SetOperation op, bool all, Node *larg, Node *rarg);
 static Node *doNegate(Node *n, int location);
@@ -253,7 +253,8 @@ static void doNegateFloat(Value *v);
 %type <oncommit> OnCommitOption
 %type <withoids> OptWithOids
 
-%type <node>	for_locking_clause opt_for_locking_clause
+%type <node>	for_locking_item
+%type <list>	for_locking_clause opt_for_locking_clause for_locking_items
 %type <list>	locked_rels_list
 %type <boolean>	opt_all
 
@@ -5400,7 +5401,7 @@ select_no_parens:
 			simple_select						{ $$ = $1; }
 			| select_clause sort_clause
 				{
-					insertSelectOptions((SelectStmt *) $1, $2, NULL,
+					insertSelectOptions((SelectStmt *) $1, $2, NIL,
 										NULL, NULL);
 					$$ = $1;
 				}
@@ -5644,12 +5645,27 @@ having_clause:
 		;
 
 for_locking_clause:
+			for_locking_items						{ $$ = $1; }
+			| FOR READ ONLY							{ $$ = NIL; }
+		;
+
+opt_for_locking_clause:
+			for_locking_clause						{ $$ = $1; }
+			| /* EMPTY */							{ $$ = NIL; }
+		;
+
+for_locking_items:
+			for_locking_item						{ $$ = list_make1($1); }
+			| for_locking_items for_locking_item	{ $$ = lappend($1, $2); }
+		;
+
+for_locking_item:
 			FOR UPDATE locked_rels_list opt_nowait
 				{
 					LockingClause *n = makeNode(LockingClause);
 					n->lockedRels = $3;
 					n->forUpdate = TRUE;
-					n->nowait = $4;
+					n->noWait = $4;
 					$$ = (Node *) n;
 				}
 			| FOR SHARE locked_rels_list opt_nowait
@@ -5657,15 +5673,9 @@ for_locking_clause:
 					LockingClause *n = makeNode(LockingClause);
 					n->lockedRels = $3;
 					n->forUpdate = FALSE;
-					n->nowait = $4;
+					n->noWait = $4;
 					$$ = (Node *) n;
 				}
-			| FOR READ ONLY							{ $$ = NULL; }
-		;
-
-opt_for_locking_clause:
-			for_locking_clause						{ $$ = $1; }
-			| /* EMPTY */							{ $$ = NULL; }
 		;
 
 locked_rels_list:
@@ -8976,7 +8986,7 @@ findLeftmostSelect(SelectStmt *node)
  */
 static void
 insertSelectOptions(SelectStmt *stmt,
-					List *sortClause, Node *lockingClause,
+					List *sortClause, List *lockingClause,
 					Node *limitOffset, Node *limitCount)
 {
 	/*
@@ -8991,14 +9001,8 @@ insertSelectOptions(SelectStmt *stmt,
 					 errmsg("multiple ORDER BY clauses not allowed")));
 		stmt->sortClause = sortClause;
 	}
-	if (lockingClause)
-	{
-		if (stmt->lockingClause)
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("multiple FOR UPDATE/FOR SHARE clauses not allowed")));
-		stmt->lockingClause = (LockingClause *) lockingClause;
-	}
+	/* We can handle multiple locking clauses, though */
+	stmt->lockingClause = list_concat(stmt->lockingClause, lockingClause);
 	if (limitOffset)
 	{
 		if (stmt->limitOffset)

src/backend/parser/parse_relation.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.122 2006/03/23 00:19:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.123 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1001,6 +1001,8 @@ addRangeTableEntryForJoin(ParseState *pstate,
 
 /*
  * Has the specified refname been selected FOR UPDATE/FOR SHARE?
+ *
+ * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE.
  */
 static bool
 isLockedRel(ParseState *pstate, char *refname)
@@ -1008,9 +1010,13 @@ isLockedRel(ParseState *pstate, char *refname)
 	/* Outer loop to check parent query levels as well as this one */
 	while (pstate != NULL)
 	{
-		if (pstate->p_locking_clause)
+		ListCell   *l;
+
+		foreach(l, pstate->p_locking_clause)
 		{
-			if (pstate->p_locking_clause->lockedRels == NIL)
+			LockingClause *lc = (LockingClause *) lfirst(l);
+
+			if (lc->lockedRels == NIL)
 			{
 				/* all tables used in query */
 				return true;
@@ -1018,11 +1024,11 @@ isLockedRel(ParseState *pstate, char *refname)
 			else
 			{
 				/* just the named tables */
-				ListCell   *l;
+				ListCell   *l2;
 
-				foreach(l, pstate->p_locking_clause->lockedRels)
+				foreach(l2, lc->lockedRels)
 				{
-					char	   *rname = strVal(lfirst(l));
+					char	   *rname = strVal(lfirst(l2));
 
 					if (strcmp(refname, rname) == 0)
 						return true;
@@ -1702,6 +1708,26 @@ get_tle_by_resno(List *tlist, AttrNumber resno)
 	return NULL;
 }
 
+/*
+ * Given a Query and rangetable index, return relation's RowMarkClause if any
+ *
+ * Returns NULL if relation is not selected FOR UPDATE/SHARE
+ */
+RowMarkClause *
+get_rowmark(Query *qry, Index rtindex)
+{
+	ListCell   *l;
+
+	foreach(l, qry->rowMarks)
+	{
+		RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+
+		if (rc->rti == rtindex)
+			return rc;
+	}
+	return NULL;
+}
+
 /*
  *	given relation and att name, return attnum of variable
  *

src/backend/parser/parse_type.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_type.c,v 1.80 2006/04/04 19:35:35 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_type.c,v 1.81 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -432,7 +432,7 @@ parseTypeString(const char *str, Oid *type_id, int32 *typmod)
 		stmt->sortClause != NIL ||
 		stmt->limitOffset != NULL ||
 		stmt->limitCount != NULL ||
-		stmt->lockingClause != NULL ||
+		stmt->lockingClause != NIL ||
 		stmt->op != SETOP_NONE)
 		goto fail;
 	if (list_length(stmt->targetList) != 1)

src/backend/rewrite/rewriteHandler.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.162 2006/04/05 22:11:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.163 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -130,7 +130,7 @@ AcquireRewriteLocks(Query *parsetree)
 				 */
 				if (rt_index == parsetree->resultRelation)
 					lockmode = RowExclusiveLock;
-				else if (list_member_int(parsetree->rowMarks, rt_index))
+				else if (get_rowmark(parsetree, rt_index))
 					lockmode = RowShareLock;
 				else
 					lockmode = AccessShareLock;
@@ -907,6 +907,7 @@ ApplyRetrieveRule(Query *parsetree,
 	Query	   *rule_action;
 	RangeTblEntry *rte,
 			   *subrte;
+	RowMarkClause *rc;
 
 	if (list_length(rule->actions) != 1)
 		elog(ERROR, "expected just one rule action");
@@ -954,20 +955,20 @@ ApplyRetrieveRule(Query *parsetree,
 	/*
 	 * FOR UPDATE/SHARE of view?
 	 */
-	if (list_member_int(parsetree->rowMarks, rt_index))
+	if ((rc = get_rowmark(parsetree, rt_index)) != NULL)
 	{
 		/*
 		 * Remove the view from the list of rels that will actually be marked
-		 * FOR UPDATE/SHARE by the executor.  It will still be access- checked
+		 * FOR UPDATE/SHARE by the executor.  It will still be access-checked
 		 * for write access, though.
 		 */
-		parsetree->rowMarks = list_delete_int(parsetree->rowMarks, rt_index);
+		parsetree->rowMarks = list_delete_ptr(parsetree->rowMarks, rc);
 
 		/*
 		 * Set up the view's referenced tables as if FOR UPDATE/SHARE.
 		 */
-		markQueryForLocking(rule_action, parsetree->forUpdate,
-							parsetree->rowNoWait, true);
+		markQueryForLocking(rule_action, rc->forUpdate,
+							rc->noWait, true);
 	}
 
 	return parsetree;
@@ -987,20 +988,6 @@ markQueryForLocking(Query *qry, bool forUpdate, bool noWait, bool skipOldNew)
 	Index		rti = 0;
 	ListCell   *l;
 
-	if (qry->rowMarks)
-	{
-		if (forUpdate != qry->forUpdate)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("cannot use both FOR UPDATE and FOR SHARE in one query")));
-		if (noWait != qry->rowNoWait)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot use both wait and NOWAIT in one query")));
-	}
-	qry->forUpdate = forUpdate;
-	qry->rowNoWait = noWait;
-
 	foreach(l, qry->rtable)
 	{
 		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
@@ -1014,7 +1001,7 @@ markQueryForLocking(Query *qry, bool forUpdate, bool noWait, bool skipOldNew)
 
 		if (rte->rtekind == RTE_RELATION)
 		{
-			qry->rowMarks = list_append_unique_int(qry->rowMarks, rti);
+			applyLockingClause(qry, rti, forUpdate, noWait);
 			rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
 		}
 		else if (rte->rtekind == RTE_SUBQUERY)

src/backend/rewrite/rewriteManip.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.98 2006/04/05 22:11:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.99 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -240,7 +240,11 @@ OffsetVarNodes(Node *node, int offset, int sublevels_up)
 			if (qry->resultRelation)
 				qry->resultRelation += offset;
 			foreach(l, qry->rowMarks)
-				lfirst_int(l) += offset;
+			{
+				RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+
+				rc->rti += offset;
+			}
 		}
 		query_tree_walker(qry, OffsetVarNodes_walker,
 						  (void *) &context, 0);
@@ -395,8 +399,10 @@ ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
 				qry->resultRelation = new_index;
 			foreach(l, qry->rowMarks)
 			{
-				if (lfirst_int(l) == rt_index)
-					lfirst_int(l) = new_index;
+				RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+
+				if (rc->rti == rt_index)
+					rc->rti = new_index;
 			}
 		}
 		query_tree_walker(qry, ChangeVarNodes_walker,

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.256 2006/04/15 17:45:41 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.257 2006/04/30 18:30:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1796,7 +1796,7 @@ CreateQueryTag(Query *parsetree)
 				tag = "SELECT INTO";
 			else if (parsetree->rowMarks != NIL)
 			{
-				if (parsetree->forUpdate)
+				if (((RowMarkClause *) linitial(parsetree->rowMarks))->forUpdate)
 					tag = "SELECT FOR UPDATE";
 				else
 					tag = "SELECT FOR SHARE";

src/backend/utils/adt/ruleutils.c

@@ -2,7 +2,7 @@
  * ruleutils.c	- Functions to convert stored expressions/querytrees
  *				back to source text
  *
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.220 2006/04/22 01:26:00 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.221 2006/04/30 18:30:40 tgl Exp $
  **********************************************************************/
 
 #include "postgres.h"
@@ -1858,27 +1858,21 @@ get_select_query_def(Query *query, deparse_context *context,
 			get_rule_expr(query->limitCount, context, false);
 	}
 
-	/* Add the FOR UPDATE/SHARE clause if present */
-	if (query->rowMarks != NIL)
+	/* Add FOR UPDATE/SHARE clauses if present */
+	foreach(l, query->rowMarks)
 	{
-		if (query->forUpdate)
-			appendContextKeyword(context, " FOR UPDATE OF ",
+		RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+		RangeTblEntry *rte = rt_fetch(rc->rti, query->rtable);
+
+		if (rc->forUpdate)
+			appendContextKeyword(context, " FOR UPDATE",
 								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
 		else
-			appendContextKeyword(context, " FOR SHARE OF ",
+			appendContextKeyword(context, " FOR SHARE",
 								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
-		sep = "";
-		foreach(l, query->rowMarks)
-		{
-			int			rtindex = lfirst_int(l);
-			RangeTblEntry *rte = rt_fetch(rtindex, query->rtable);
-
-			appendStringInfo(buf, "%s%s",
-							 sep,
-							 quote_identifier(rte->eref->aliasname));
-			sep = ", ";
-		}
-		if (query->rowNoWait)
+		appendStringInfo(buf, " OF %s",
+						 quote_identifier(rte->eref->aliasname));
+		if (rc->noWait)
 			appendStringInfo(buf, " NOWAIT");
 	}
 }