Add LOCK A,B,C functionality as LOCK A;LOCK B;LOCK C; as agreed.

Neil Padgett

1 files changed, 94 insertions, 17 deletions

diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 744129f726f..827608363cb 100644
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.136 2001/07/16 05:06:57 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.137 2001/08/04 19:38:59 momjian Exp $
  *
  * NOTES
  *	  The PerformAddAttribute() code, like most of the relation
@@ -1984,8 +1984,7 @@ needs_toast_table(Relation rel)
 		MAXALIGN(data_length);
 	return (tuple_length > TOAST_TUPLE_THRESHOLD);
 }
-
-
+	
 /*
  *
  * LOCK TABLE
@@ -1994,26 +1993,104 @@ needs_toast_table(Relation rel)
 void
 LockTableCommand(LockStmt *lockstmt)
 {
-	Relation	rel;
-	int			aclresult;
+	int         relCnt;
 
-	rel = heap_openr(lockstmt->relname, NoLock);
+	relCnt = length(lockstmt -> rellist);
 
-	if (rel->rd_rel->relkind != RELKIND_RELATION)
-		elog(ERROR, "LOCK TABLE: %s is not a table", lockstmt->relname);
+	/* Handle a single relation lock specially to avoid overhead on likely the
+	   most common case */
 
-	if (lockstmt->mode == AccessShareLock)
-		aclresult = pg_aclcheck(lockstmt->relname, GetUserId(), ACL_SELECT);
-	else
-		aclresult = pg_aclcheck(lockstmt->relname, GetUserId(),
-								ACL_UPDATE | ACL_DELETE);
+	if(relCnt == 1)
+	{
+
+		/* Locking a single table */
+
+		Relation	rel;
+		int			aclresult;
+		char *relname;
+
+		relname = strVal(lfirst(lockstmt->rellist));
+
+		freeList(lockstmt->rellist);
+
+		rel = heap_openr(relname, NoLock);
+
+		if (rel->rd_rel->relkind != RELKIND_RELATION)
+			elog(ERROR, "LOCK TABLE: %s is not a table", relname);
+
+		if (lockstmt->mode == AccessShareLock)
+			aclresult = pg_aclcheck(relname, GetUserId(),
+									ACL_SELECT);
+		else
+			aclresult = pg_aclcheck(relname, GetUserId(),
+									ACL_UPDATE | ACL_DELETE);
+
+		if (aclresult != ACLCHECK_OK)
+			elog(ERROR, "LOCK TABLE: permission denied");
+
+		LockRelation(rel, lockstmt->mode);
+
+		pfree(relname);
+
+		heap_close(rel, NoLock);	/* close rel, keep lock */
+	} 
+	else 
+	{
+		List *p;
+		Relation *RelationArray;
+		Relation *pRel;
 
-	if (aclresult != ACLCHECK_OK)
-		elog(ERROR, "LOCK TABLE: permission denied");
+		/* Locking multiple tables */
 
-	LockRelation(rel, lockstmt->mode);
+		/* Create an array of relations */
 
-	heap_close(rel, NoLock);	/* close rel, keep lock */
+		RelationArray = palloc(relCnt * sizeof(Relation));
+		pRel = RelationArray;
+
+		/* Iterate over the list and populate the relation array */
+
+		foreach(p, lockstmt->rellist)
+		{
+			char* relname = strVal(lfirst(p));
+			int			aclresult;
+
+			*pRel = heap_openr(relname, NoLock);
+
+			if ((*pRel)->rd_rel->relkind != RELKIND_RELATION)
+				elog(ERROR, "LOCK TABLE: %s is not a table", 
+					 relname);
+
+			if (lockstmt->mode == AccessShareLock)
+				aclresult = pg_aclcheck(relname, GetUserId(),
+										ACL_SELECT);
+			else
+				aclresult = pg_aclcheck(relname, GetUserId(),
+										ACL_UPDATE | ACL_DELETE);
+
+			if (aclresult != ACLCHECK_OK)
+				elog(ERROR, "LOCK TABLE: permission denied");
+
+			pRel++;
+			pfree(relname);
+		}
+
+		/* Now, lock all the relations, closing each after it is locked
+		   (Keeping the locks)
+		 */
+
+		for(pRel = RelationArray;
+			pRel < RelationArray + relCnt;
+			pRel++)
+			{
+				LockRelation(*pRel, lockstmt->mode);
+
+				heap_close(*pRel, NoLock);
+			}
+
+		/* Free the relation array */
+
+		pfree(RelationArray);
+	}
 }