diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 0c10fc49cc..c09e9249ea 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 1.21 2007/01/05 22:19:22 momjian Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gist/gistutil.c,v 1.22 2007/04/09 22:03:57 tgl Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -559,10 +559,11 @@ GISTInitBuffer(Buffer b, uint32 f)
 	PageInit(page, pageSize, sizeof(GISTPageOpaqueData));
 
 	opaque = GistPageGetOpaque(page);
-	opaque->flags = f;
-	opaque->rightlink = InvalidBlockNumber;
 	/* page was already zeroed by PageInit, so this is not needed: */
 	/* memset(&(opaque->nsn), 0, sizeof(GistNSN)); */
+	opaque->rightlink = InvalidBlockNumber;
+	opaque->flags = f;
+	opaque->gist_page_id = GIST_PAGE_ID;
 }
 
 /*
diff --git a/src/backend/access/hash/hashovfl.c b/src/backend/access/hash/hashovfl.c
index abd9972ced..2a844f40d4 100644
--- a/src/backend/access/hash/hashovfl.c
+++ b/src/backend/access/hash/hashovfl.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashovfl.c,v 1.54 2007/01/05 22:19:22 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashovfl.c,v 1.55 2007/04/09 22:03:57 tgl Exp $
  *
  * NOTES
  *	  Overflow pages look like ordinary relation pages.
@@ -141,7 +141,7 @@ _hash_addovflpage(Relation rel, Buffer metabuf, Buffer buf)
 	ovflopaque->hasho_nextblkno = InvalidBlockNumber;
 	ovflopaque->hasho_bucket = pageopaque->hasho_bucket;
 	ovflopaque->hasho_flag = LH_OVERFLOW_PAGE;
-	ovflopaque->hasho_filler = HASHO_FILL;
+	ovflopaque->hasho_page_id = HASHO_PAGE_ID;
 
 	MarkBufferDirty(ovflbuf);
 
@@ -529,7 +529,7 @@ _hash_initbitmap(Relation rel, HashMetaPage metap, BlockNumber blkno)
 	op->hasho_nextblkno = InvalidBlockNumber;
 	op->hasho_bucket = -1;
 	op->hasho_flag = LH_BITMAP_PAGE;
-	op->hasho_filler = HASHO_FILL;
+	op->hasho_page_id = HASHO_PAGE_ID;
 
 	/* set all of the bits to 1 */
 	freep = HashPageGetBitmap(pg);
diff --git a/src/backend/access/hash/hashpage.c b/src/backend/access/hash/hashpage.c
index 97eb3c379e..c368bcd05d 100644
--- a/src/backend/access/hash/hashpage.c
+++ b/src/backend/access/hash/hashpage.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashpage.c,v 1.64 2007/01/29 23:22:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashpage.c,v 1.65 2007/04/09 22:03:57 tgl Exp $
  *
  * NOTES
  *	  Postgres hash pages look like ordinary relation pages.  The opaque
@@ -252,7 +252,7 @@ _hash_metapinit(Relation rel)
 	pageopaque->hasho_nextblkno = InvalidBlockNumber;
 	pageopaque->hasho_bucket = -1;
 	pageopaque->hasho_flag = LH_META_PAGE;
-	pageopaque->hasho_filler = HASHO_FILL;
+	pageopaque->hasho_page_id = HASHO_PAGE_ID;
 
 	metap = (HashMetaPage) pg;
 
@@ -310,7 +310,7 @@ _hash_metapinit(Relation rel)
 		pageopaque->hasho_nextblkno = InvalidBlockNumber;
 		pageopaque->hasho_bucket = i;
 		pageopaque->hasho_flag = LH_BUCKET_PAGE;
-		pageopaque->hasho_filler = HASHO_FILL;
+		pageopaque->hasho_page_id = HASHO_PAGE_ID;
 		_hash_wrtbuf(rel, buf);
 	}
 
@@ -654,7 +654,7 @@ _hash_splitbucket(Relation rel,
 	nopaque->hasho_nextblkno = InvalidBlockNumber;
 	nopaque->hasho_bucket = nbucket;
 	nopaque->hasho_flag = LH_BUCKET_PAGE;
-	nopaque->hasho_filler = HASHO_FILL;
+	nopaque->hasho_page_id = HASHO_PAGE_ID;
 
 	/*
 	 * Partition the tuples in the old bucket between the old bucket and the
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index b5e7686303..33c0ee0082 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.84 2007/04/06 22:33:42 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtutils.c,v 1.85 2007/04/09 22:04:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1263,11 +1263,13 @@ _bt_start_vacuum(Relation rel)
 
 	LWLockAcquire(BtreeVacuumLock, LW_EXCLUSIVE);
 
-	/* Assign the next cycle ID, being careful to avoid zero */
-	do
-	{
-		result = ++(btvacinfo->cycle_ctr);
-	} while (result == 0);
+	/*
+	 * Assign the next cycle ID, being careful to avoid zero as well as
+	 * the reserved high values.
+	 */
+	result = ++(btvacinfo->cycle_ctr);
+	if (result == 0 || result > MAX_BT_CYCLE_ID)
+		result = btvacinfo->cycle_ctr = 1;
 
 	/* Let's just make sure there's no entry already for this index */
 	for (i = 0; i < btvacinfo->num_vacuums; i++)
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 80f2374996..4e4259363d 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -3,7 +3,7 @@
  *	  header file for postgres inverted index access method implementation.
  *
  *	Copyright (c) 2006, PostgreSQL Global Development Group
- *	$PostgreSQL: pgsql/src/include/access/gin.h,v 1.10 2007/01/31 15:09:45 teodor Exp $
+ *	$PostgreSQL: pgsql/src/include/access/gin.h,v 1.11 2007/04/09 22:04:04 tgl Exp $
  *--------------------------------------------------------------------------
  */
 
@@ -31,41 +31,27 @@
 #define GIN_CONSISTENT_PROC			   4
 #define GINNProcs					   4
 
-typedef XLogRecPtr GinNSN;
-
 /*
  * Page opaque data in a inverted index page.
+ *
+ * Note: GIN does not include a page ID word as do the other index types.
+ * This is OK because the opaque data is only 8 bytes and so can be reliably
+ * distinguished by size.  Revisit this if the size ever increases.
  */
 typedef struct GinPageOpaqueData
 {
-	uint16		flags;
+	BlockNumber rightlink;		/* next page if any */
 	OffsetNumber maxoff;		/* number entries on GIN_DATA page: number of
 								 * heap ItemPointer on GIN_DATA|GIN_LEAF page
 								 * and number of records on GIN_DATA &
 								 * ~GIN_LEAF page */
-	BlockNumber rightlink;
+	uint16		flags;			/* see bit definitions below */
 } GinPageOpaqueData;
 
 typedef GinPageOpaqueData *GinPageOpaque;
 
 #define GIN_ROOT_BLKNO	(0)
 
-typedef struct
-{
-	BlockIdData child_blkno;	/* use it instead of BlockNumber to save space
-								 * on page */
-	ItemPointerData key;
-} PostingItem;
-
-#define PostingItemGetBlockNumber(pointer) \
-	BlockIdGetBlockNumber(&(pointer)->child_blkno)
-
-#define PostingItemSetBlockNumber(pointer, blockNumber) \
-	BlockIdSet(&((pointer)->child_blkno), (blockNumber))
-
-/*
- * Page opaque data in a inverted index page.
- */
 #define GIN_DATA		  (1 << 0)
 #define GIN_LEAF		  (1 << 1)
 #define GIN_DELETED		  (1 << 2)
@@ -98,8 +84,21 @@ typedef struct
 #define GinItemPointerGetOffsetNumber(pointer) \
 	((pointer)->ip_posid)
 
+typedef struct
+{
+	BlockIdData child_blkno;	/* use it instead of BlockNumber to save space
+								 * on page */
+	ItemPointerData key;
+} PostingItem;
+
+#define PostingItemGetBlockNumber(pointer) \
+	BlockIdGetBlockNumber(&(pointer)->child_blkno)
+
+#define PostingItemSetBlockNumber(pointer, blockNumber) \
+	BlockIdSet(&((pointer)->child_blkno), (blockNumber))
+
 /*
- * Support work on IndexTuuple on leaf pages
+ * Support work on IndexTuple on leaf pages
  */
 #define GinGetNPosting(itup)	GinItemPointerGetOffsetNumber(&(itup)->t_tid)
 #define GinSetNPosting(itup,n)	ItemPointerSetOffsetNumber(&(itup)->t_tid,(n))
diff --git a/src/include/access/gist.h b/src/include/access/gist.h
index 52d3a2fe1a..eab6a01bfd 100644
--- a/src/include/access/gist.h
+++ b/src/include/access/gist.h
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/gist.h,v 1.57 2007/01/05 22:19:50 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/gist.h,v 1.58 2007/04/09 22:04:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -56,25 +56,30 @@
 /*
  * Page opaque data in a GiST index page.
  */
-#define F_LEAF			(1 << 0)
-#define F_DELETED		(1 << 1)
+#define F_LEAF				(1 << 0)
+#define F_DELETED			(1 << 1)
 #define F_TUPLES_DELETED	(1 << 2)
 
 typedef XLogRecPtr GistNSN;
 
 typedef struct GISTPageOpaqueData
 {
-	uint32		flags;			/* 29 bits are unused for now */
-	BlockNumber rightlink;
-
-	/*
-	 * the only meaning - change this value if page split.
-	 */
-	GistNSN		nsn;
+	GistNSN		nsn;			/* this value must change on page split */
+	BlockNumber rightlink;		/* next page if any */
+	uint16		flags;			/* see bit definitions above */
+	uint16		gist_page_id;	/* for identification of GiST indexes */
 } GISTPageOpaqueData;
 
 typedef GISTPageOpaqueData *GISTPageOpaque;
 
+/*
+ * The page ID is for the convenience of pg_filedump and similar utilities,
+ * which otherwise would have a hard time telling pages of different index
+ * types apart.  It should be the last 2 bytes on the page.  This is more or
+ * less "free" due to alignment considerations.
+ */
+#define GIST_PAGE_ID		0xFF81
+
 /*
  * This is the Split Vector to be returned by the PickSplit method.
  * PickSplit should check spl_(r|l)datum_exists. If it is 'true',
diff --git a/src/include/access/hash.h b/src/include/access/hash.h
index 7ba8fbfc2f..114a684dbc 100644
--- a/src/include/access/hash.h
+++ b/src/include/access/hash.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.77 2007/04/02 03:49:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.78 2007/04/09 22:04:05 tgl Exp $
  *
  * NOTES
  *		modeled after Margo Seltzer's hash implementation for unix.
@@ -56,20 +56,18 @@ typedef struct HashPageOpaqueData
 	BlockNumber hasho_nextblkno;	/* next ovfl blkno */
 	Bucket		hasho_bucket;	/* bucket number this pg belongs to */
 	uint16		hasho_flag;		/* page type code, see above */
-	uint16		hasho_filler;	/* available for future use */
-
-	/*
-	 * We presently set hasho_filler to HASHO_FILL (0x1234); this is for the
-	 * convenience of pg_filedump, which otherwise would have a hard time
-	 * telling HashPageOpaqueData from BTPageOpaqueData.  If we ever need that
-	 * space for some other purpose, pg_filedump will have to find another
-	 * way.
-	 */
+	uint16		hasho_page_id;	/* for identification of hash indexes */
 } HashPageOpaqueData;
 
 typedef HashPageOpaqueData *HashPageOpaque;
 
-#define HASHO_FILL		0x1234
+/*
+ * The page ID is for the convenience of pg_filedump and similar utilities,
+ * which otherwise would have a hard time telling pages of different index
+ * types apart.  It should be the last 2 bytes on the page.  This is more or
+ * less "free" due to alignment considerations.
+ */
+#define HASHO_PAGE_ID		0xFF80
 
 /*
  *	HashScanOpaqueData is private state for a hash index scan.
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index ff78cf1f71..53e10c80e8 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.111 2007/02/08 05:05:53 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/nbtree.h,v 1.112 2007/04/09 22:04:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -40,8 +40,8 @@ typedef uint16 BTCycleId;
  *	stored into both halves of the split page.	(If VACUUM is not running,
  *	both pages receive zero cycleids.)	This allows VACUUM to detect whether
  *	a page was split since it started, with a small probability of false match
- *	if the page was last split some exact multiple of 65536 VACUUMs ago.
- *	Also, during a split, the BTP_SPLIT_END flag is cleared in the left
+ *	if the page was last split some exact multiple of MAX_BT_CYCLE_ID VACUUMs
+ *	ago.  Also, during a split, the BTP_SPLIT_END flag is cleared in the left
  *	(original) page, and set in the right page, but only if the next page
  *	to its right has a different cycleid.
  *
@@ -73,6 +73,15 @@ typedef BTPageOpaqueData *BTPageOpaque;
 #define BTP_SPLIT_END	(1 << 5)	/* rightmost page of split group */
 #define BTP_HAS_GARBAGE (1 << 6)	/* page has LP_DELETEd tuples */
 
+/*
+ * The max allowed value of a cycle ID is a bit less than 64K.  This is
+ * for convenience of pg_filedump and similar utilities: we want to use
+ * the last 2 bytes of special space as an index type indicator, and
+ * restricting cycle ID lets btree use that space for vacuum cycle IDs
+ * while still allowing index type to be identified.
+ */
+#define MAX_BT_CYCLE_ID		0xFF7F
+
 
 /*
  * The Meta page is always the first page in the btree index.
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index f18415a4fd..7b2c966101 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.401 2007/04/06 22:33:43 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.402 2007/04/09 22:04:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200704061
+#define CATALOG_VERSION_NO	200704091
 
 #endif