Add NOWAIT option to SELECT FOR UPDATE/SHARE.

Original patch by Hans-Juergen Schoenig, revisions by Karel Zak
and Tom Lane.

4 files changed, 77 insertions, 73 deletions

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index a9211cfe931..099bb714831 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.323 2005/07/28 22:27:00 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.324 2005/08/01 20:31:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -134,7 +134,7 @@ static void transformFKConstraints(ParseState *pstate,
 					   bool isAddConstraint);
 static void applyColumnNames(List *dst, List *src);
 static List *getSetColTypes(ParseState *pstate, Node *node);
-static void transformLocking(Query *qry, List *lockedRels, bool forUpdate);
+static void transformLockingClause(Query *qry, LockingClause *lc);
 static void transformConstraintAttrs(List *constraintList);
 static void transformColumnType(ParseState *pstate, ColumnDef *column);
 static void release_pstate_resources(ParseState *pstate);
@@ -1812,8 +1812,8 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 
 	qry->commandType = CMD_SELECT;
 
-	/* make FOR UPDATE/FOR SHARE list available to addRangeTableEntry */
-	pstate->p_lockedRels = stmt->lockedRels;
+	/* make FOR UPDATE/FOR SHARE info available to addRangeTableEntry */
+	pstate->p_locking_clause = stmt->lockingClause;
 
 	/* process the FROM clause */
 	transformFromClause(pstate, stmt->fromClause);
@@ -1872,8 +1872,8 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
 		parseCheckAggregates(pstate, qry);
 
-	if (stmt->lockedRels != NIL)
-		transformLocking(qry, stmt->lockedRels, stmt->forUpdate);
+	if (stmt->lockingClause)
+		transformLockingClause(qry, stmt->lockingClause);
 
 	return qry;
 }
@@ -1901,8 +1901,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	List	   *sortClause;
 	Node	   *limitOffset;
 	Node	   *limitCount;
-	List	   *lockedRels;
-	bool		forUpdate;
+	LockingClause *lockingClause;
 	Node	   *node;
 	ListCell   *left_tlist,
 			   *dtlist;
@@ -1940,16 +1939,15 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	sortClause = stmt->sortClause;
 	limitOffset = stmt->limitOffset;
 	limitCount = stmt->limitCount;
-	lockedRels = stmt->lockedRels;
-	forUpdate = stmt->forUpdate;
+	lockingClause = stmt->lockingClause;
 
 	stmt->sortClause = NIL;
 	stmt->limitOffset = NULL;
 	stmt->limitCount = NULL;
-	stmt->lockedRels = NIL;
+	stmt->lockingClause = NULL;
 
 	/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
-	if (lockedRels)
+	if (lockingClause)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
@@ -2089,8 +2087,8 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
 		parseCheckAggregates(pstate, qry);
 
-	if (lockedRels != NIL)
-		transformLocking(qry, lockedRels, forUpdate);
+	if (lockingClause)
+		transformLockingClause(qry, lockingClause);
 
 	return qry;
 }
@@ -2114,7 +2112,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
 				(errcode(ERRCODE_SYNTAX_ERROR),
 				 errmsg("INTO is only allowed on first SELECT of UNION/INTERSECT/EXCEPT")));
 	/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
-	if (stmt->lockedRels)
+	if (stmt->lockingClause)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
@@ -2134,7 +2132,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
 	{
 		Assert(stmt->larg != NULL && stmt->rarg != NULL);
 		if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
-			stmt->lockedRels)
+			stmt->lockingClause)
 			isLeaf = true;
 		else
 			isLeaf = false;
@@ -2760,24 +2758,40 @@ CheckSelectLocking(Query *qry, bool forUpdate)
  * in rewriteHandler.c.
  */
 static void
-transformLocking(Query *qry, List *lockedRels, bool forUpdate)
+transformLockingClause(Query *qry, LockingClause *lc)
 {
+	List	   *lockedRels = lc->lockedRels;
 	List	   *rowMarks;
 	ListCell   *l;
 	ListCell   *rt;
 	Index		i;
+	LockingClause *allrels;
 
-	if (qry->rowMarks && forUpdate != qry->forUpdate)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot use both FOR UPDATE and FOR SHARE in one query")));
-	qry->forUpdate = forUpdate;
+	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);
+
+	/* 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;
 
-	CheckSelectLocking(qry, forUpdate);
-	
 	rowMarks = qry->rowMarks;
 
-	if (linitial(lockedRels) == NULL)
+	if (lockedRels == NIL)
 	{
 		/* all regular tables used in query */
 		i = 0;
@@ -2799,8 +2813,7 @@ transformLocking(Query *qry, List *lockedRels, bool forUpdate)
 					 * FOR UPDATE/SHARE of subquery is propagated to all
 					 * of subquery's rels
 					 */
-					transformLocking(rte->subquery, list_make1(NULL),
-									 forUpdate);
+					transformLockingClause(rte->subquery, allrels);
 					break;
 				default:
 					/* ignore JOIN, SPECIAL, FUNCTION RTEs */
@@ -2836,8 +2849,7 @@ transformLocking(Query *qry, List *lockedRels, bool forUpdate)
 							 * FOR UPDATE/SHARE of subquery is propagated to
 							 * all of subquery's rels
 							 */
-							transformLocking(rte->subquery, list_make1(NULL),
-											 forUpdate);
+							transformLockingClause(rte->subquery, allrels);
 							break;
 						case RTE_JOIN:
 							ereport(ERROR,
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 8e79355cdd5..768fb4ada75 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.506 2005/08/01 04:03:56 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.507 2005/08/01 20:31:09 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -87,7 +87,7 @@ static List *check_func_name(List *names);
 static List *extractArgTypes(List *parameters);
 static SelectStmt *findLeftmostSelect(SelectStmt *node);
 static void insertSelectOptions(SelectStmt *stmt,
-								List *sortClause, List *lockingClause,
+								List *sortClause, Node *lockingClause,
 								Node *limitOffset, Node *limitCount);
 static Node *makeSetOp(SetOperation op, bool all, Node *larg, Node *rarg);
 static Node *doNegate(Node *n);
@@ -132,7 +132,7 @@ static void doNegateFloat(Value *v);
 
 %type <node>	stmt schema_stmt
 		AlterDatabaseStmt AlterDatabaseSetStmt AlterDomainStmt AlterGroupStmt
-		AlterObjectSchemaStmt AlterOwnerStmt AlterSeqStmt AlterTableStmt 
+		AlterObjectSchemaStmt AlterOwnerStmt AlterSeqStmt AlterTableStmt
 		AlterUserStmt AlterUserSetStmt AlterRoleStmt AlterRoleSetStmt
 		AnalyzeStmt ClosePortalStmt ClusterStmt CommentStmt
 		ConstraintsSetStmt CopyStmt CreateAsStmt CreateCastStmt
@@ -165,7 +165,7 @@ static void doNegateFloat(Value *v);
 
 %type <dbehavior>	opt_drop_behavior
 
-%type <list>	createdb_opt_list alterdb_opt_list copy_opt_list 
+%type <list>	createdb_opt_list alterdb_opt_list copy_opt_list
 				transaction_mode_list
 %type <defelt>	createdb_opt_item alterdb_opt_item copy_opt_item
 				transaction_mode_item
@@ -240,8 +240,8 @@ static void doNegateFloat(Value *v);
 %type <oncommit> OnCommitOption
 %type <withoids> OptWithOids WithOidsAs
 
-%type <list>	for_locking_clause opt_for_locking_clause
-				update_list
+%type <node>	for_locking_clause opt_for_locking_clause
+%type <list>	locked_rels_list
 %type <boolean>	opt_all
 
 %type <node>	join_outer join_qual
@@ -4555,7 +4555,7 @@ opt_equal:	'='										{}
  *****************************************************************************/
 
 AlterDatabaseStmt:
- 			ALTER DATABASE database_name opt_with alterdb_opt_list
+			ALTER DATABASE database_name opt_with alterdb_opt_list
 				 {
 					AlterDatabaseStmt *n = makeNode(AlterDatabaseStmt);
 					n->dbname = $3;
@@ -5070,7 +5070,7 @@ lock_type:	ACCESS SHARE					{ $$ = AccessShareLock; }
 			| ACCESS EXCLUSIVE				{ $$ = AccessExclusiveLock; }
 		;
 
-opt_nowait:	NOWAIT 			{ $$ = TRUE; }
+opt_nowait:	NOWAIT							{ $$ = TRUE; }
 			| /*EMPTY*/						{ $$ = FALSE; }
 		;
 
@@ -5191,7 +5191,7 @@ select_no_parens:
 			simple_select						{ $$ = $1; }
 			| select_clause sort_clause
 				{
-					insertSelectOptions((SelectStmt *) $1, $2, NIL,
+					insertSelectOptions((SelectStmt *) $1, $2, NULL,
 										NULL, NULL);
 					$$ = $1;
 				}
@@ -5424,14 +5424,6 @@ select_offset_value:
 			a_expr									{ $$ = $1; }
 		;
 
-/*
- *	jimmy bell-style recursive queries aren't supported in the
- *	current system.
- *
- *	...however, recursive addattr and rename supported.  make special
- *	cases for these.
- */
-
 group_clause:
 			GROUP_P BY expr_list					{ $$ = $3; }
 			| /*EMPTY*/								{ $$ = NIL; }
@@ -5443,8 +5435,22 @@ having_clause:
 		;
 
 for_locking_clause:
-			FOR UPDATE update_list					{ $$ = lcons(makeString("for_update"), $3); }
-			| FOR SHARE update_list					{ $$ = lcons(makeString("for_share"), $3); }
+			FOR UPDATE locked_rels_list opt_nowait
+				{
+					LockingClause *n = makeNode(LockingClause);
+					n->lockedRels = $3;
+					n->forUpdate = TRUE;
+					n->nowait = $4;
+					$$ = (Node *) n;
+				}
+			| FOR SHARE locked_rels_list opt_nowait
+				{
+					LockingClause *n = makeNode(LockingClause);
+					n->lockedRels = $3;
+					n->forUpdate = FALSE;
+					n->nowait = $4;
+					$$ = (Node *) n;
+				}
 			| FOR READ ONLY							{ $$ = NULL; }
 		;
 
@@ -5453,9 +5459,9 @@ opt_for_locking_clause:
 			| /* EMPTY */							{ $$ = NULL; }
 		;
 
-update_list:
+locked_rels_list:
 			OF name_list							{ $$ = $2; }
-			| /* EMPTY */							{ $$ = list_make1(NULL); }
+			| /* EMPTY */							{ $$ = NIL; }
 		;
 
 /*****************************************************************************
@@ -8691,7 +8697,7 @@ findLeftmostSelect(SelectStmt *node)
  */
 static void
 insertSelectOptions(SelectStmt *stmt,
-					List *sortClause, List *lockingClause,
+					List *sortClause, Node *lockingClause,
 					Node *limitOffset, Node *limitCount)
 {
 	/*
@@ -8708,25 +8714,11 @@ insertSelectOptions(SelectStmt *stmt,
 	}
 	if (lockingClause)
 	{
-		Value	   *type;
-
-		if (stmt->lockedRels)
+		if (stmt->lockingClause)
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 					 errmsg("multiple FOR UPDATE/FOR SHARE clauses not allowed")));
-
-		Assert(list_length(lockingClause) > 1);
-		/* 1st is Value node containing "for_update" or "for_share" */
-		type = (Value *) linitial(lockingClause);
-		Assert(IsA(type, String));
-		if (strcmp(strVal(type), "for_update") == 0)
-			stmt->forUpdate = true;
-		else if (strcmp(strVal(type), "for_share") == 0)
-			stmt->forUpdate = false;
-		else
-			elog(ERROR, "invalid first node in locking clause");
-
-		stmt->lockedRels = list_delete_first(lockingClause);
+		stmt->lockingClause = (LockingClause *) lockingClause;
 	}
 	if (limitOffset)
 	{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 51d200736b0..85984cb1d9e 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.112 2005/06/28 05:08:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.113 2005/08/01 20:31:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -903,9 +903,9 @@ isLockedRel(ParseState *pstate, char *refname)
 	/* Outer loop to check parent query levels as well as this one */
 	while (pstate != NULL)
 	{
-		if (pstate->p_lockedRels != NIL)
+		if (pstate->p_locking_clause)
 		{
-			if (linitial(pstate->p_lockedRels) == NULL)
+			if (pstate->p_locking_clause->lockedRels == NIL)
 			{
 				/* all tables used in query */
 				return true;
@@ -915,7 +915,7 @@ isLockedRel(ParseState *pstate, char *refname)
 				/* just the named tables */
 				ListCell   *l;
 
-				foreach(l, pstate->p_lockedRels)
+				foreach(l, pstate->p_locking_clause->lockedRels)
 				{
 					char	   *rname = strVal(lfirst(l));
 
diff --git a/src/backend/parser/parse_type.c b/src/backend/parser/parse_type.c
index d8fba16b555..008c1fe6a54 100644
--- a/src/backend/parser/parse_type.c
+++ b/src/backend/parser/parse_type.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_type.c,v 1.75 2005/05/29 18:24:13 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_type.c,v 1.76 2005/08/01 20:31:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -423,7 +423,7 @@ parseTypeString(const char *str, Oid *type_id, int32 *typmod)
 		stmt->sortClause != NIL ||
 		stmt->limitOffset != NULL ||
 		stmt->limitCount != NULL ||
-		stmt->lockedRels != NIL ||
+		stmt->lockingClause != NULL ||
 		stmt->op != SETOP_NONE)
 		goto fail;
 	if (list_length(stmt->targetList) != 1)