diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index f6ae7747d71..248ec259567 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gist/gistutil.c,v 1.29 2008/06/19 00:46:03 alvherre Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gist/gistutil.c,v 1.30 2008/07/13 20:45:46 tgl Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -591,8 +591,7 @@ gistcheckpage(Relation rel, Buffer buf)
 	/*
 	 * Additionally check that the special area looks sane.
 	 */
-	if (((PageHeader) (page))->pd_special !=
-		(BLCKSZ - MAXALIGN(sizeof(GISTPageOpaqueData))))
+	if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GISTPageOpaqueData)))
 		ereport(ERROR,
 				(errcode(ERRCODE_INDEX_CORRUPTED),
 				 errmsg("index \"%s\" contains corrupted page at block %u",
diff --git a/src/backend/access/hash/hashutil.c b/src/backend/access/hash/hashutil.c
index 0789eb8caef..29cdf24529a 100644
--- a/src/backend/access/hash/hashutil.c
+++ b/src/backend/access/hash/hashutil.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.55 2008/06/19 00:46:03 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.56 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -164,8 +164,7 @@ _hash_checkpage(Relation rel, Buffer buf, int flags)
 	/*
 	 * Additionally check that the special area looks sane.
 	 */
-	if (((PageHeader) (page))->pd_special !=
-		(BLCKSZ - MAXALIGN(sizeof(HashPageOpaqueData))))
+	if (PageGetSpecialSize(page) != MAXALIGN(sizeof(HashPageOpaqueData)))
 		ereport(ERROR,
 				(errcode(ERRCODE_INDEX_CORRUPTED),
 				 errmsg("index \"%s\" contains corrupted page at block %u",
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 482e53dfaa9..cb2f428afe6 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.260 2008/06/19 00:46:03 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.261 2008/07/13 20:45:47 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1343,7 +1343,7 @@ heap_fetch(Relation relation,
 	ItemPointer tid = &(tuple->t_self);
 	ItemId		lp;
 	Buffer		buffer;
-	PageHeader	dp;
+	Page		page;
 	OffsetNumber offnum;
 	bool		valid;
 
@@ -1356,14 +1356,14 @@ heap_fetch(Relation relation,
 	 * Need share lock on buffer to examine tuple commit status.
 	 */
 	LockBuffer(buffer, BUFFER_LOCK_SHARE);
-	dp = (PageHeader) BufferGetPage(buffer);
+	page = BufferGetPage(buffer);
 
 	/*
 	 * We'd better check for out-of-range offnum in case of VACUUM since the
 	 * TID was obtained.
 	 */
 	offnum = ItemPointerGetOffsetNumber(tid);
-	if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(dp))
+	if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(page))
 	{
 		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 		if (keep_buf)
@@ -1380,7 +1380,7 @@ heap_fetch(Relation relation,
 	/*
 	 * get the item line pointer corresponding to the requested tid
 	 */
-	lp = PageGetItemId(dp, offnum);
+	lp = PageGetItemId(page, offnum);
 
 	/*
 	 * Must check for deleted tuple.
@@ -1402,7 +1402,7 @@ heap_fetch(Relation relation,
 	/*
 	 * fill in *tuple fields
 	 */
-	tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
+	tuple->t_data = (HeapTupleHeader) PageGetItem(page, lp);
 	tuple->t_len = ItemIdGetLength(lp);
 	tuple->t_tableOid = RelationGetRelid(relation);
 
@@ -1627,7 +1627,7 @@ heap_get_latest_tid(Relation relation,
 	for (;;)
 	{
 		Buffer		buffer;
-		PageHeader	dp;
+		Page		page;
 		OffsetNumber offnum;
 		ItemId		lp;
 		HeapTupleData tp;
@@ -1638,7 +1638,7 @@ heap_get_latest_tid(Relation relation,
 		 */
 		buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&ctid));
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
-		dp = (PageHeader) BufferGetPage(buffer);
+		page = BufferGetPage(buffer);
 
 		/*
 		 * Check for bogus item number.  This is not treated as an error
@@ -1646,12 +1646,12 @@ heap_get_latest_tid(Relation relation,
 		 * just assume that the prior tid is OK and return it unchanged.
 		 */
 		offnum = ItemPointerGetOffsetNumber(&ctid);
-		if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(dp))
+		if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(page))
 		{
 			UnlockReleaseBuffer(buffer);
 			break;
 		}
-		lp = PageGetItemId(dp, offnum);
+		lp = PageGetItemId(page, offnum);
 		if (!ItemIdIsNormal(lp))
 		{
 			UnlockReleaseBuffer(buffer);
@@ -1660,7 +1660,7 @@ heap_get_latest_tid(Relation relation,
 
 		/* OK to access the tuple */
 		tp.t_self = ctid;
-		tp.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
+		tp.t_data = (HeapTupleHeader) PageGetItem(page, lp);
 		tp.t_len = ItemIdGetLength(lp);
 
 		/*
@@ -1964,7 +1964,7 @@ heap_delete(Relation relation, ItemPointer tid,
 	TransactionId xid = GetCurrentTransactionId();
 	ItemId		lp;
 	HeapTupleData tp;
-	PageHeader	dp;
+	Page		page;
 	Buffer		buffer;
 	bool		have_tuple_lock = false;
 	bool		iscombo;
@@ -1974,11 +1974,11 @@ heap_delete(Relation relation, ItemPointer tid,
 	buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
 	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 
-	dp = (PageHeader) BufferGetPage(buffer);
-	lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
+	page = BufferGetPage(buffer);
+	lp = PageGetItemId(page, ItemPointerGetOffsetNumber(tid));
 	Assert(ItemIdIsNormal(lp));
 
-	tp.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
+	tp.t_data = (HeapTupleHeader) PageGetItem(page, lp);
 	tp.t_len = ItemIdGetLength(lp);
 	tp.t_self = *tid;
 
@@ -2112,7 +2112,7 @@ l1:
 	 * the subsequent page pruning will be a no-op and the hint will be
 	 * cleared.
 	 */
-	PageSetPrunable(dp, xid);
+	PageSetPrunable(page, xid);
 
 	/* store transaction information of xact deleting the tuple */
 	tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
@@ -2150,8 +2150,8 @@ l1:
 
 		recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_DELETE, rdata);
 
-		PageSetLSN(dp, recptr);
-		PageSetTLI(dp, ThisTimeLineID);
+		PageSetLSN(page, recptr);
+		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
@@ -2276,7 +2276,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 	ItemId		lp;
 	HeapTupleData oldtup;
 	HeapTuple	heaptup;
-	PageHeader	dp;
+	Page		page;
 	Buffer		buffer,
 				newbuf;
 	bool		need_toast,
@@ -2306,11 +2306,11 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 	buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(otid));
 	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 
-	dp = (PageHeader) BufferGetPage(buffer);
-	lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(otid));
+	page = BufferGetPage(buffer);
+	lp = PageGetItemId(page, ItemPointerGetOffsetNumber(otid));
 	Assert(ItemIdIsNormal(lp));
 
-	oldtup.t_data = (HeapTupleHeader) PageGetItem(dp, lp);
+	oldtup.t_data = (HeapTupleHeader) PageGetItem(page, lp);
 	oldtup.t_len = ItemIdGetLength(lp);
 	oldtup.t_self = *otid;
 
@@ -2491,7 +2491,7 @@ l2:
 					  HeapTupleHasExternal(newtup) ||
 					  newtup->t_len > TOAST_TUPLE_THRESHOLD);
 
-	pagefree = PageGetHeapFreeSpace((Page) dp);
+	pagefree = PageGetHeapFreeSpace(page);
 
 	newtupsize = MAXALIGN(newtup->t_len);
 
@@ -2557,7 +2557,7 @@ l2:
 			/* Re-acquire the lock on the old tuple's page. */
 			LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 			/* Re-check using the up-to-date free space */
-			pagefree = PageGetHeapFreeSpace((Page) dp);
+			pagefree = PageGetHeapFreeSpace(page);
 			if (newtupsize > pagefree)
 			{
 				/*
@@ -2603,7 +2603,7 @@ l2:
 	else
 	{
 		/* Set a hint that the old page could use prune/defrag */
-		PageSetFull(dp);
+		PageSetFull(page);
 	}
 
 	/* NO EREPORT(ERROR) from here till changes are logged */
@@ -2621,7 +2621,7 @@ l2:
 	 * not to optimize for aborts.	Note that heap_xlog_update must be kept in
 	 * sync if this decision changes.
 	 */
-	PageSetPrunable(dp, xid);
+	PageSetPrunable(page, xid);
 
 	if (use_hot_update)
 	{
@@ -2946,7 +2946,7 @@ heap_lock_tuple(Relation relation, HeapTuple tuple, Buffer *buffer,
 	HTSU_Result result;
 	ItemPointer tid = &(tuple->t_self);
 	ItemId		lp;
-	PageHeader	dp;
+	Page		page;
 	TransactionId xid;
 	TransactionId xmax;
 	uint16		old_infomask;
@@ -2959,11 +2959,11 @@ heap_lock_tuple(Relation relation, HeapTuple tuple, Buffer *buffer,
 	*buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
 	LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
 
-	dp = (PageHeader) BufferGetPage(*buffer);
-	lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
+	page = BufferGetPage(*buffer);
+	lp = PageGetItemId(page, ItemPointerGetOffsetNumber(tid));
 	Assert(ItemIdIsNormal(lp));
 
-	tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
+	tuple->t_data = (HeapTupleHeader) PageGetItem(page, lp);
 	tuple->t_len = ItemIdGetLength(lp);
 	tuple->t_tableOid = RelationGetRelid(relation);
 
@@ -3302,8 +3302,8 @@ l3:
 
 		recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_LOCK, rdata);
 
-		PageSetLSN(dp, recptr);
-		PageSetTLI(dp, ThisTimeLineID);
+		PageSetLSN(page, recptr);
+		PageSetTLI(page, ThisTimeLineID);
 	}
 
 	END_CRIT_SECTION();
diff --git a/src/backend/access/heap/hio.c b/src/backend/access/heap/hio.c
index df902a02f3b..6db80590de6 100644
--- a/src/backend/access/heap/hio.c
+++ b/src/backend/access/heap/hio.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/hio.c,v 1.71 2008/06/08 22:00:47 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/hio.c,v 1.72 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -107,7 +107,7 @@ RelationGetBufferForTuple(Relation relation, Size len,
 						  Buffer otherBuffer, bool use_fsm)
 {
 	Buffer		buffer = InvalidBuffer;
-	Page		pageHeader;
+	Page		page;
 	Size		pageFreeSpace,
 				saveFreeSpace;
 	BlockNumber targetBlock,
@@ -218,8 +218,8 @@ RelationGetBufferForTuple(Relation relation, Size len,
 		 * Now we can check to see if there's enough free space here. If so,
 		 * we're done.
 		 */
-		pageHeader = (Page) BufferGetPage(buffer);
-		pageFreeSpace = PageGetHeapFreeSpace(pageHeader);
+		page = BufferGetPage(buffer);
+		pageFreeSpace = PageGetHeapFreeSpace(page);
 		if (len + saveFreeSpace <= pageFreeSpace)
 		{
 			/* use this page as future insert target, too */
@@ -303,16 +303,16 @@ RelationGetBufferForTuple(Relation relation, Size len,
 	 * is empty (this should never happen, but if it does we don't want to
 	 * risk wiping out valid data).
 	 */
-	pageHeader = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer);
 
-	if (!PageIsNew((PageHeader) pageHeader))
+	if (!PageIsNew(page))
 		elog(ERROR, "page %u of relation \"%s\" should be empty but is not",
 			 BufferGetBlockNumber(buffer),
 			 RelationGetRelationName(relation));
 
-	PageInit(pageHeader, BufferGetPageSize(buffer), 0);
+	PageInit(page, BufferGetPageSize(buffer), 0);
 
-	if (len > PageGetHeapFreeSpace(pageHeader))
+	if (len > PageGetHeapFreeSpace(page))
 	{
 		/* We should not get here given the test at the top */
 		elog(PANIC, "tuple is too big: size %lu", (unsigned long) len);
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index be630b225b9..bdffd6dc64d 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/pruneheap.c,v 1.15 2008/06/19 00:46:03 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/pruneheap.c,v 1.16 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -72,7 +72,7 @@ static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum);
 void
 heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
 {
-	PageHeader	dp = (PageHeader) BufferGetPage(buffer);
+	Page		page = BufferGetPage(buffer);
 	Size		minfree;
 
 	/*
@@ -81,7 +81,7 @@ heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
 	 * Forget it if page is not hinted to contain something prunable that's
 	 * older than OldestXmin.
 	 */
-	if (!PageIsPrunable(dp, OldestXmin))
+	if (!PageIsPrunable(page, OldestXmin))
 		return;
 
 	/*
@@ -100,7 +100,7 @@ heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
 											 HEAP_DEFAULT_FILLFACTOR);
 	minfree = Max(minfree, BLCKSZ / 10);
 
-	if (PageIsFull(dp) || PageGetHeapFreeSpace((Page) dp) < minfree)
+	if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
 	{
 		/* OK, try to get exclusive buffer lock */
 		if (!ConditionalLockBufferForCleanup(buffer))
@@ -112,7 +112,7 @@ heap_page_prune_opt(Relation relation, Buffer buffer, TransactionId OldestXmin)
 		 * prune. (We needn't recheck PageIsPrunable, since no one else could
 		 * have pruned while we hold pin.)
 		 */
-		if (PageIsFull(dp) || PageGetHeapFreeSpace((Page) dp) < minfree)
+		if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
 		{
 			/* OK to prune (though not to remove redirects) */
 			(void) heap_page_prune(relation, buffer, OldestXmin, false, true);
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 70445de3744..2cc5ebe8443 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.109 2008/05/12 00:00:45 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtpage.c,v 1.110 2008/07/13 20:45:47 tgl Exp $
  *
  *	NOTES
  *	   Postgres btree pages look like ordinary relation pages.	The opaque
@@ -436,8 +436,7 @@ _bt_checkpage(Relation rel, Buffer buf)
 	/*
 	 * Additionally check that the special area looks sane.
 	 */
-	if (((PageHeader) (page))->pd_special !=
-		(BLCKSZ - MAXALIGN(sizeof(BTPageOpaqueData))))
+	if (PageGetSpecialSize(page) != MAXALIGN(sizeof(BTPageOpaqueData)))
 		ereport(ERROR,
 				(errcode(ERRCODE_INDEX_CORRUPTED),
 				 errmsg("index \"%s\" contains corrupted page at block %u",
@@ -555,7 +554,7 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 
 		/* Initialize the new page before returning it */
 		page = BufferGetPage(buf);
-		Assert(PageIsNew((PageHeader) page));
+		Assert(PageIsNew(page));
 		_bt_pageinit(page, BufferGetPageSize(buf));
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2e832db4b15..72e531d3dc3 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.315 2008/06/30 22:10:43 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.316 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1017,19 +1017,19 @@ static bool
 XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites,
 				XLogRecPtr *lsn, BkpBlock *bkpb)
 {
-	PageHeader	page;
+	Page		page;
 
-	page = (PageHeader) BufferGetBlock(rdata->buffer);
+	page = BufferGetPage(rdata->buffer);
 
 	/*
 	 * XXX We assume page LSN is first data on *every* page that can be passed
 	 * to XLogInsert, whether it otherwise has the standard page layout or
 	 * not.
 	 */
-	*lsn = page->pd_lsn;
+	*lsn = PageGetLSN(page);
 
 	if (doPageWrites &&
-		XLByteLE(page->pd_lsn, RedoRecPtr))
+		XLByteLE(PageGetLSN(page), RedoRecPtr))
 	{
 		/*
 		 * The page needs to be backed up, so set up *bkpb
@@ -1040,8 +1040,8 @@ XLogCheckBuffer(XLogRecData *rdata, bool doPageWrites,
 		if (rdata->buffer_std)
 		{
 			/* Assume we can omit data between pd_lower and pd_upper */
-			uint16		lower = page->pd_lower;
-			uint16		upper = page->pd_upper;
+			uint16		lower = ((PageHeader) page)->pd_lower;
+			uint16		upper = ((PageHeader) page)->pd_upper;
 
 			if (lower >= SizeOfPageHeaderData &&
 				upper > lower &&
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 9a2f18d5318..3e2d5046da6 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.56 2008/06/19 00:46:03 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.57 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -279,7 +279,7 @@ XLogReadBuffer(RelFileNode rnode, BlockNumber blkno, bool init)
 		/* check that page has been initialized */
 		Page		page = (Page) BufferGetPage(buffer);
 
-		if (PageIsNew((PageHeader) page))
+		if (PageIsNew(page))
 		{
 			UnlockReleaseBuffer(buffer);
 			log_invalid_page(rnode, blkno, true);
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index cdc60db1e5c..87b857826c1 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.153 2008/06/12 09:12:30 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.154 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -109,7 +109,7 @@ DefineSequence(CreateSeqStmt *seq)
 	Oid			seqoid;
 	Relation	rel;
 	Buffer		buf;
-	PageHeader	page;
+	Page		page;
 	sequence_magic *sm;
 	HeapTuple	tuple;
 	TupleDesc	tupDesc;
@@ -212,9 +212,9 @@ DefineSequence(CreateSeqStmt *seq)
 	buf = ReadBuffer(rel, P_NEW);
 	Assert(BufferGetBlockNumber(buf) == 0);
 
-	page = (PageHeader) BufferGetPage(buf);
+	page = BufferGetPage(buf);
 
-	PageInit((Page) page, BufferGetPageSize(buf), sizeof(sequence_magic));
+	PageInit(page, BufferGetPageSize(buf), sizeof(sequence_magic));
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 	sm->magic = SEQ_MAGIC;
 
@@ -954,7 +954,7 @@ init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel)
 static Form_pg_sequence
 read_info(SeqTable elm, Relation rel, Buffer *buf)
 {
-	PageHeader	page;
+	Page		page;
 	ItemId		lp;
 	HeapTupleData tuple;
 	sequence_magic *sm;
@@ -963,7 +963,7 @@ read_info(SeqTable elm, Relation rel, Buffer *buf)
 	*buf = ReadBuffer(rel, 0);
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
-	page = (PageHeader) BufferGetPage(*buf);
+	page = BufferGetPage(*buf);
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -972,7 +972,7 @@ read_info(SeqTable elm, Relation rel, Buffer *buf)
 
 	lp = PageGetItemId(page, FirstOffsetNumber);
 	Assert(ItemIdIsNormal(lp));
-	tuple.t_data = (HeapTupleHeader) PageGetItem((Page) page, lp);
+	tuple.t_data = (HeapTupleHeader) PageGetItem(page, lp);
 
 	seq = (Form_pg_sequence) GETSTRUCT(&tuple);
 
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 76a373343de..cc9fd5d08da 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.234 2008/05/15 00:17:39 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.235 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2203,17 +2203,17 @@ ltrmark:;
 	}
 	else
 	{
-		PageHeader	dp;
+		Page		page;
 		ItemId		lp;
 
 		buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
 
-		dp = (PageHeader) BufferGetPage(buffer);
-		lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
+		page = BufferGetPage(buffer);
+		lp = PageGetItemId(page, ItemPointerGetOffsetNumber(tid));
 
 		Assert(ItemIdIsNormal(lp));
 
-		tuple.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
+		tuple.t_data = (HeapTupleHeader) PageGetItem(page, lp);
 		tuple.t_len = ItemIdGetLength(lp);
 		tuple.t_self = *tid;
 		tuple.t_tableOid = RelationGetRelid(relation);
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index a0f146aa38e..cb9a07b77d5 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.147 2008/06/19 00:46:04 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.148 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -429,7 +429,7 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				tuple_width += sizeof(HeapTupleHeaderData);
 				tuple_width += sizeof(ItemPointerData);
 				/* note: integer division is intentional here */
-				density = (BLCKSZ - sizeof(PageHeaderData)) / tuple_width;
+				density = (BLCKSZ - SizeOfPageHeaderData) / tuple_width;
 			}
 			*tuples = rint(density * (double) curpages);
 			break;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index bd3d38c6307..bd8529d617c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.233 2008/06/19 00:46:05 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.234 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -263,7 +263,7 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, BlockNumber blockNum,
 		 * always have left a zero-filled buffer, complain if not PageIsNew.
 		 */
 		bufBlock = isLocalBuf ? LocalBufHdrGetBlock(bufHdr) : BufHdrGetBlock(bufHdr);
-		if (!PageIsNew((PageHeader) bufBlock))
+		if (!PageIsNew((Page) bufBlock))
 			ereport(ERROR,
 					(errmsg("unexpected data beyond EOF in block %u of relation %u/%u/%u",
 							blockNum, smgr->smgr_rnode.spcNode, smgr->smgr_rnode.dbNode, smgr->smgr_rnode.relNode),
diff --git a/src/include/access/hash.h b/src/include/access/hash.h
index 4d8cd79e9a8..0dab2b6ae91 100644
--- a/src/include/access/hash.h
+++ b/src/include/access/hash.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.88 2008/06/19 00:46:05 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.89 2008/07/13 20:45:47 tgl Exp $
  *
  * NOTES
  *		modeled after Margo Seltzer's hash implementation for unix.
@@ -166,10 +166,10 @@ typedef HashMetaPageData *HashMetaPage;
  * Maximum size of a hash index item (it's okay to have only one per page)
  */
 #define HashMaxItemSize(page) \
-	(PageGetPageSize(page) - \
-	 sizeof(PageHeaderData) - \
-	 MAXALIGN(sizeof(HashPageOpaqueData)) - \
-	 sizeof(ItemIdData))
+	MAXALIGN_DOWN(PageGetPageSize(page) - \
+				  SizeOfPageHeaderData - \
+				  sizeof(ItemIdData) - \
+				  MAXALIGN(sizeof(HashPageOpaqueData)))
 
 #define HASH_MIN_FILLFACTOR			10
 #define HASH_DEFAULT_FILLFACTOR		75
diff --git a/src/include/access/htup.h b/src/include/access/htup.h
index 7a77d438933..8bfdf26697e 100644
--- a/src/include/access/htup.h
+++ b/src/include/access/htup.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.99 2008/05/12 00:00:53 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/htup.h,v 1.100 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -362,12 +362,12 @@ do { \
  * other stuff that has to be on a disk page.  Since heap pages use no
  * "special space", there's no deduction for that.
  *
- * NOTE: we do not need to count an ItemId for the tuple because
- * sizeof(PageHeaderData) includes the first ItemId on the page.  But beware
- * of assuming that, say, you can fit 2 tuples of size MaxHeapTupleSize/2
- * on the same page.
+ * NOTE: we allow for the ItemId that must point to the tuple, ensuring that
+ * an otherwise-empty page can indeed hold a tuple of this size.  Because
+ * ItemIds and tuples have different alignment requirements, don't assume that
+ * you can, say, fit 2 tuples of size MaxHeapTupleSize/2 on the same page.
  */
-#define MaxHeapTupleSize  (BLCKSZ - MAXALIGN(sizeof(PageHeaderData)))
+#define MaxHeapTupleSize  (BLCKSZ - MAXALIGN(SizeOfPageHeaderData + sizeof(ItemIdData)))
 
 /*
  * MaxHeapTuplesPerPage is an upper bound on the number of tuples that can
@@ -381,7 +381,7 @@ do { \
  * require increases in the size of work arrays.
  */
 #define MaxHeapTuplesPerPage	\
-	((int) ((BLCKSZ - offsetof(PageHeaderData, pd_linp)) / \
+	((int) ((BLCKSZ - SizeOfPageHeaderData) / \
 			(MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) + sizeof(ItemIdData))))
 
 /*
diff --git a/src/include/access/itup.h b/src/include/access/itup.h
index eb637b81ea4..ae53accde7c 100644
--- a/src/include/access/itup.h
+++ b/src/include/access/itup.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/itup.h,v 1.49 2008/01/01 19:45:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/itup.h,v 1.50 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -134,7 +134,7 @@ typedef IndexAttributeBitMapData *IndexAttributeBitMap;
  * must be maxaligned, and it must have an associated item pointer.
  */
 #define MaxIndexTuplesPerPage	\
-	((int) ((BLCKSZ - offsetof(PageHeaderData, pd_linp)) / \
+	((int) ((BLCKSZ - SizeOfPageHeaderData) / \
 			(MAXALIGN(sizeof(IndexTupleData) + 1) + sizeof(ItemIdData))))
 
 
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 9b0e8d0cf77..e0bc10c0642 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.120 2008/06/19 00:46:06 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.121 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -113,13 +113,10 @@ typedef struct BTMetaPageData
  *
  * We actually need to be able to fit three items on every page,
  * so restrict any one item to 1/3 the per-page available space.
- *
- * Note: sizeof(PageHeaderData) includes the first ItemId, but we have
- * to allow for 2 more, as well as the end-of-page special space.
  */
 #define BTMaxItemSize(page) \
 	MAXALIGN_DOWN((PageGetPageSize(page) - \
-				   MAXALIGN(sizeof(PageHeaderData) + 2*sizeof(ItemIdData)) - \
+				   MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
 				   MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
 
 /*
diff --git a/src/include/access/tuptoaster.h b/src/include/access/tuptoaster.h
index 7d1ba7d2f82..a87aee62dfc 100644
--- a/src/include/access/tuptoaster.h
+++ b/src/include/access/tuptoaster.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 2000-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/include/access/tuptoaster.h,v 1.40 2008/06/19 00:46:06 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/tuptoaster.h,v 1.41 2008/07/13 20:45:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -46,10 +46,9 @@
  */
 #define TOAST_TUPLES_PER_PAGE	4
 
-/* Note: sizeof(PageHeaderData) includes the first ItemId on the page */
 #define TOAST_TUPLE_THRESHOLD	\
 	MAXALIGN_DOWN((BLCKSZ - \
-				   MAXALIGN(sizeof(PageHeaderData) + (TOAST_TUPLES_PER_PAGE-1) * sizeof(ItemIdData))) \
+				   MAXALIGN(SizeOfPageHeaderData + TOAST_TUPLES_PER_PAGE * sizeof(ItemIdData))) \
 				  / TOAST_TUPLES_PER_PAGE)
 
 #define TOAST_TUPLE_TARGET		TOAST_TUPLE_THRESHOLD
@@ -73,10 +72,9 @@
  */
 #define EXTERN_TUPLES_PER_PAGE	4		/* tweak only this */
 
-/* Note: sizeof(PageHeaderData) includes the first ItemId on the page */
 #define EXTERN_TUPLE_MAX_SIZE	\
 	MAXALIGN_DOWN((BLCKSZ - \
-				   MAXALIGN(sizeof(PageHeaderData) + (EXTERN_TUPLES_PER_PAGE-1) * sizeof(ItemIdData))) \
+				   MAXALIGN(SizeOfPageHeaderData + EXTERN_TUPLES_PER_PAGE * sizeof(ItemIdData))) \
 				  / EXTERN_TUPLES_PER_PAGE)
 
 #define TOAST_MAX_CHUNK_SIZE	\