Mega-commit to make heap_open/heap_openr/heap_close take an

additional argument specifying the kind of lock to acquire/release (or
'NoLock' to do no lock processing).  Ensure that all relations are locked
with some appropriate lock level before being examined --- this ensures
that relevant shared-inval messages have been processed and should prevent
problems caused by concurrent VACUUM.  Fix several bugs having to do with
mismatched increment/decrement of relation ref count and mismatched
heap_open/close (which amounts to the same thing).  A bogus ref count on
a relation doesn't matter much *unless* a SI Inval message happens to
arrive at the wrong time, which is probably why we got away with this
sloppiness for so long.  Repair missing grab of AccessExclusiveLock in
DROP TABLE, ALTER/RENAME TABLE, etc, as noted by Hiroshi.
Recommend 'make clean all' after pulling this update; I modified the
Relation struct layout slightly.
Will post further discussion to pghackers list shortly.

1 files changed, 16 insertions, 66 deletions

diff --git a/src/backend/storage/lmgr/lmgr.c b/src/backend/storage/lmgr/lmgr.c
index 839533952b..2aaaf69e83 100644
--- a/src/backend/storage/lmgr/lmgr.c
+++ b/src/backend/storage/lmgr/lmgr.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.34 1999/09/04 18:42:14 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.35 1999/09/18 19:07:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,11 +20,12 @@
 
 
 #include "postgres.h"
+
 #include "access/transam.h"
 #include "catalog/catalog.h"
+#include "miscadmin.h"
 #include "utils/inval.h"
 
-extern Oid	MyDatabaseId;
 
 static LOCKMASK LockConflicts[] = {
 	(int) NULL,
@@ -106,37 +107,25 @@ InitLockTable()
 /*
  * RelationInitLockInfo
  *		Initializes the lock information in a relation descriptor.
+ *
+ *		relcache.c must call this during creation of any reldesc.
  */
 void
 RelationInitLockInfo(Relation relation)
 {
-	LockInfo	info;
 	char	   *relname;
-	MemoryContext oldcxt;
-	extern Oid	MyDatabaseId;	/* XXX use include */
-	extern GlobalMemory CacheCxt;
 
 	Assert(RelationIsValid(relation));
 	Assert(OidIsValid(RelationGetRelid(relation)));
 
-	info = (LockInfo) relation->lockInfo;
-
-	if (LockInfoIsValid(info))
-		return;
-
 	relname = (char *) RelationGetRelationName(relation);
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
-	info = (LockInfo) palloc(sizeof(LockInfoData));
-	MemoryContextSwitchTo(oldcxt);
+	relation->rd_lockInfo.lockRelId.relId = RelationGetRelid(relation);
 
-	info->lockRelId.relId = RelationGetRelid(relation);
 	if (IsSharedSystemRelationName(relname))
-		info->lockRelId.dbId = InvalidOid;
+		relation->rd_lockInfo.lockRelId.dbId = InvalidOid;
 	else
-		info->lockRelId.dbId = MyDatabaseId;
-
-	relation->lockInfo = (Pointer) info;
+		relation->rd_lockInfo.lockRelId.dbId = MyDatabaseId;
 }
 
 /*
@@ -145,20 +134,14 @@ RelationInitLockInfo(Relation relation)
 void
 LockRelation(Relation relation, LOCKMODE lockmode)
 {
-	LockInfo	lockinfo;
 	LOCKTAG		tag;
 
 	if (LockingDisabled())
 		return;
 
-	if (!LockInfoIsValid(relation->lockInfo))
-		RelationInitLockInfo(relation);
-
-	lockinfo = (LockInfo) relation->lockInfo;
-
 	MemSet(&tag, 0, sizeof(tag));
-	tag.relId = lockinfo->lockRelId.relId;
-	tag.dbId = lockinfo->lockRelId.dbId;
+	tag.relId = relation->rd_lockInfo.lockRelId.relId;
+	tag.dbId = relation->rd_lockInfo.lockRelId.dbId;
 	tag.objId.blkno = InvalidBlockNumber;
 
 	LockAcquire(LockTableId, &tag, lockmode);
@@ -180,28 +163,17 @@ LockRelation(Relation relation, LOCKMODE lockmode)
 void
 UnlockRelation(Relation relation, LOCKMODE lockmode)
 {
-	LockInfo	lockinfo;
 	LOCKTAG		tag;
 
 	if (LockingDisabled())
 		return;
 
-	lockinfo = (LockInfo) relation->lockInfo;
-
-	if (!LockInfoIsValid(lockinfo))
-	{
-		elog(ERROR,
-			 "Releasing a lock on %s with invalid lock information",
-			 RelationGetRelationName(relation));
-	}
-
 	MemSet(&tag, 0, sizeof(tag));
-	tag.relId = lockinfo->lockRelId.relId;
-	tag.dbId = lockinfo->lockRelId.dbId;
+	tag.relId = relation->rd_lockInfo.lockRelId.relId;
+	tag.dbId = relation->rd_lockInfo.lockRelId.dbId;
 	tag.objId.blkno = InvalidBlockNumber;
 
 	LockRelease(LockTableId, &tag, lockmode);
-	return;
 }
 
 /*
@@ -210,24 +182,17 @@ UnlockRelation(Relation relation, LOCKMODE lockmode)
 void
 LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode)
 {
-	LockInfo	lockinfo;
 	LOCKTAG		tag;
 
 	if (LockingDisabled())
 		return;
 
-	if (!LockInfoIsValid(relation->lockInfo))
-		RelationInitLockInfo(relation);
-
-	lockinfo = (LockInfo) relation->lockInfo;
-
 	MemSet(&tag, 0, sizeof(tag));
-	tag.relId = lockinfo->lockRelId.relId;
-	tag.dbId = lockinfo->lockRelId.dbId;
+	tag.relId = relation->rd_lockInfo.lockRelId.relId;
+	tag.dbId = relation->rd_lockInfo.lockRelId.dbId;
 	tag.objId.blkno = blkno;
 
 	LockAcquire(LockTableId, &tag, lockmode);
-	return;
 }
 
 /*
@@ -236,28 +201,17 @@ LockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode)
 void
 UnlockPage(Relation relation, BlockNumber blkno, LOCKMODE lockmode)
 {
-	LockInfo	lockinfo;
 	LOCKTAG		tag;
 
 	if (LockingDisabled())
 		return;
 
-	lockinfo = (LockInfo) relation->lockInfo;
-
-	if (!LockInfoIsValid(lockinfo))
-	{
-		elog(ERROR,
-			 "Releasing a lock on %s with invalid lock information",
-			 RelationGetRelationName(relation));
-	}
-
 	MemSet(&tag, 0, sizeof(tag));
-	tag.relId = lockinfo->lockRelId.relId;
-	tag.dbId = lockinfo->lockRelId.dbId;
+	tag.relId = relation->rd_lockInfo.lockRelId.relId;
+	tag.dbId = relation->rd_lockInfo.lockRelId.dbId;
 	tag.objId.blkno = blkno;
 
 	LockRelease(LockTableId, &tag, lockmode);
-	return;
 }
 
 void
@@ -274,7 +228,6 @@ XactLockTableInsert(TransactionId xid)
 	tag.objId.xid = xid;
 
 	LockAcquire(LockTableId, &tag, ExclusiveLock);
-	return;
 }
 
 void
@@ -291,7 +244,6 @@ XactLockTableDelete(TransactionId xid)
 	tag.objId.xid = xid;
 
 	LockRelease(LockTableId, &tag, ExclusiveLock);
-	return;
 }
 
 void
@@ -316,6 +268,4 @@ XactLockTableWait(TransactionId xid)
 	 */
 	if (!TransactionIdDidCommit(xid) && !TransactionIdDidAbort(xid))
 		TransactionIdAbort(xid);
-
-	return;
 }