Create a new HeapTupleSatisfiesVacuum() routine in tqual.c that embodies the

validity checking rules for VACUUM.  Make some other rearrangements of the
VACUUM code to allow more code to be shared between full and lazy VACUUM.
Minor code cleanups and added comments for TransactionId manipulations.

Author: tglsfdc

src/backend/access/heap/heapam.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.122 2001/07/06 09:41:36 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.123 2001/07/12 04:11:12 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -48,11 +48,6 @@
 #include "pgstat.h"
 
 
-XLogRecPtr log_heap_move(Relation reln, Buffer oldbuf, ItemPointerData from,
-			  Buffer newbuf, HeapTuple newtup);
-XLogRecPtr log_heap_clean(Relation reln, Buffer buffer,
-			   char *unused, int unlen);
-
 /* comments are in heap_update */
 static xl_heaptid _locked_tuple_;
 static void _heap_unlock_tuple(void *data);

src/backend/access/transam/transam.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.44 2001/05/14 20:30:19 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/transam.c,v 1.45 2001/07/12 04:11:13 tgl Exp $
  *
  * NOTES
  *	  This file contains the high level access-method interface to the
@@ -24,6 +24,7 @@
 #include "catalog/catname.h"
 #include "miscadmin.h"
 
+
 static int	RecoveryCheckingEnabled(void);
 static void TransRecover(Relation logRelation);
 static bool TransactionLogTest(TransactionId transactionId, XidStatus status);
@@ -40,29 +41,11 @@ static void TransactionLogUpdate(TransactionId transactionId,
 Relation	LogRelation = (Relation) NULL;
 
 /* ----------------
- *		global variables holding cached transaction id's and statuses.
- * ----------------
- */
-TransactionId cachedTestXid;
-XidStatus	cachedTestXidStatus;
-
-/* ----------------
- *		transaction system constants
+ *		Single-item cache for results of TransactionLogTest.
  * ----------------
  */
-/* ----------------------------------------------------------------
- *		transaction system constants
- *
- *		read the comments for GetNewTransactionId in order to
- *		understand the initial values for AmiTransactionId and
- *		FirstTransactionId. -cim 3/23/90
- * ----------------------------------------------------------------
- */
-TransactionId NullTransactionId = (TransactionId) 0;
-
-TransactionId AmiTransactionId = (TransactionId) 512;
-
-TransactionId FirstTransactionId = (TransactionId) 514;
+static TransactionId cachedTestXid = NullTransactionId;
+static XidStatus	cachedTestXidStatus;
 
 /* ----------------
  *		transaction recovery state variables
@@ -76,7 +59,7 @@ TransactionId FirstTransactionId = (TransactionId) 514;
  *		goes from zero to one. -cim 3/21/90
  * ----------------
  */
-int			RecoveryCheckingEnableState = 0;
+static int		RecoveryCheckingEnableState = 0;
 
 /* ----------------
  *		recovery checking accessors
@@ -203,14 +186,9 @@ TransactionLogUpdate(TransactionId transactionId,		/* trans id to update */
 
 	/*
 	 * update (invalidate) our single item TransactionLogTest cache.
-	 *
-	 * if (status != XID_COMMIT)
-	 *
-	 * What's the hell ?! Why != XID_COMMIT ?!
 	 */
 	TransactionIdStore(transactionId, &cachedTestXid);
 	cachedTestXidStatus = status;
-
 }
 
 /* ----------------------------------------------------------------
@@ -355,17 +333,15 @@ InitializeTransactionLog(void)
 
 	/*
 	 * if we have a virgin database, we initialize the log relation by
-	 * committing the AmiTransactionId (id 512) and we initialize the
+	 * committing the AmiTransactionId and we initialize the
 	 * variable relation by setting the next available transaction id to
-	 * FirstTransactionId (id 514).  OID initialization happens as a side
+	 * FirstTransactionId.  OID initialization happens as a side
 	 * effect of bootstrapping in varsup.c.
 	 */
 	SpinAcquire(OidGenLockId);
 	if (!TransactionIdDidCommit(AmiTransactionId))
 	{
 		TransactionLogUpdate(AmiTransactionId, XID_COMMIT);
-		TransactionIdStore(AmiTransactionId, &cachedTestXid);
-		cachedTestXidStatus = XID_COMMIT;
 		Assert(!IsUnderPostmaster &&
 			   ShmemVariableCache->nextXid <= FirstTransactionId);
 		ShmemVariableCache->nextXid = FirstTransactionId;

src/backend/access/transam/transsup.c

@@ -8,20 +8,75 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.30 2001/03/22 06:16:10 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/Attic/transsup.c,v 1.31 2001/07/12 04:11:13 tgl Exp $
  *
  * NOTES
  *	  This file contains support functions for the high
  *	  level access method interface routines found in transam.c
  *
  *-------------------------------------------------------------------------
  */
-
 #include "postgres.h"
 
 #include "access/xact.h"
 #include "utils/bit.h"
 
+
+/* ----------------
+ *		transaction system version id
+ *
+ *		this is stored on the first page of the log, time and variable
+ *		relations on the first 4 bytes.  This is so that if we improve
+ *		the format of the transaction log after postgres version 2, then
+ *		people won't have to rebuild their databases.
+ *
+ *		TRANS_SYSTEM_VERSION 100 means major version 1 minor version 0.
+ *		Two databases with the same major version should be compatible,
+ *		even if their minor versions differ.
+ *
+ *		XXX This isn't actually being used!
+ * ----------------
+ */
+#define TRANS_SYSTEM_VERSION	200
+
+/* ----------------
+ *		LogRelationContents structure
+ *
+ *		This structure describes the storage of the data in the
+ *		first 128 bytes of the log relation.  This storage is never
+ *		used for transaction status because transaction id's begin
+ *		their numbering at 512.
+ *
+ *		The first 4 bytes of this relation store the version
+ *		number of the transaction system.
+ *
+ *		XXX This isn't actually being used!
+ * ----------------
+ */
+typedef struct LogRelationContentsData
+{
+	XLogRecPtr	LSN;			/* temp hack: LSN is member of any block */
+	/* so should be described in bufmgr */
+	int			TransSystemVersion;
+} LogRelationContentsData;
+
+typedef LogRelationContentsData *LogRelationContents;
+
+
+/* ----------------
+ *		BitIndexOf computes the index of the Nth xid on a given block
+ * ----------------
+ */
+#define BitIndexOf(N)	((N) * 2)
+
+/* ----------------
+ *		transaction page definitions
+ * ----------------
+ */
+#define TP_DataSize				(BLCKSZ - sizeof(XLogRecPtr))
+#define TP_NumXidStatusPerBlock (TP_DataSize * 4)
+
+
 static XidStatus TransBlockGetXidStatus(Block tblock,
 					   TransactionId transactionId);
 static void TransBlockSetXidStatus(Block tblock,
@@ -54,7 +109,7 @@ TransComputeBlockNumber(Relation relation,		/* relation to test */
 														 * test */
 						BlockNumber *blockNumberOutP)
 {
-	long		itemsPerBlock = 0;
+	uint32		itemsPerBlock = 0;
 
 	/*
 	 * we calculate the block number of our transaction by dividing the
@@ -135,10 +190,7 @@ TransBlockGetLastTransactionIdStatus(Block tblock,
 		if (xstatus != XID_INPROGRESS)
 		{
 			if (returnXidP != NULL)
-			{
-				TransactionIdStore(baseXid, returnXidP);
-				TransactionIdAdd(returnXidP, index - 1);
-			}
+				TransactionIdStore(baseXid + (index - 1), returnXidP);
 			break;
 		}
 	}

src/backend/access/transam/varsup.c

@@ -6,7 +6,7 @@
  * Copyright (c) 2000, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.40 2001/05/25 15:45:32 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/varsup.c,v 1.41 2001/07/12 04:11:13 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,8 +18,7 @@
 #include "storage/proc.h"
 
 
-/* Number of XIDs and OIDs to prefetch (preallocate) per XLOG write */
-#define VAR_XID_PREFETCH		1024
+/* Number of OIDs to prefetch (preallocate) per XLOG write */
 #define VAR_OID_PREFETCH		8192
 
 /* Spinlocks for serializing generation of XIDs and OIDs, respectively */
@@ -29,10 +28,13 @@ SPINLOCK	OidGenLockId;
 /* pointer to "variable cache" in shared memory (set up by shmem.c) */
 VariableCache ShmemVariableCache = NULL;
 
+
+/*
+ * Allocate the next XID for my new transaction.
+ */
 void
 GetNewTransactionId(TransactionId *xid)
 {
-
 	/*
 	 * During bootstrap initialization, we return the special bootstrap
 	 * transaction id.
@@ -49,10 +51,22 @@ GetNewTransactionId(TransactionId *xid)
 
 	(ShmemVariableCache->nextXid)++;
 
-	SpinRelease(XidGenLockId);
-
+	/*
+	 * Must set MyProc->xid before releasing XidGenLock.  This ensures that
+	 * when GetSnapshotData calls ReadNewTransactionId, all active XIDs
+	 * before the returned value of nextXid are already present in the shared
+	 * PROC array.  Else we have a race condition.
+	 *
+	 * XXX by storing xid into MyProc without acquiring SInvalLock, we are
+	 * relying on fetch/store of an xid to be atomic, else other backends
+	 * might see a partially-set xid here.  But holding both locks at once
+	 * would be a nasty concurrency hit (and at this writing, could cause a
+	 * deadlock against GetSnapshotData).  So for now, assume atomicity.
+	 */
 	if (MyProc != (PROC *) NULL)
 		MyProc->xid = *xid;
+
+	SpinRelease(XidGenLockId);
 }
 
 /*
@@ -61,7 +75,6 @@ GetNewTransactionId(TransactionId *xid)
 void
 ReadNewTransactionId(TransactionId *xid)
 {
-
 	/*
 	 * During bootstrap initialization, we return the special bootstrap
 	 * transaction id.