diff --git a/contrib/pageinspect/heapfuncs.c b/contrib/pageinspect/heapfuncs.c
index 6d8f6f1c74064b0b9b47e17d295833e1a5f1b11b..a78cff3179b4f4b249d3d5e92d038190cfde84ff 100644
--- a/contrib/pageinspect/heapfuncs.c
+++ b/contrib/pageinspect/heapfuncs.c
@@ -162,7 +162,7 @@ heap_page_items(PG_FUNCTION_ARGS)
 
 			tuphdr = (HeapTupleHeader) PageGetItem(page, id);
 
-			values[4] = UInt32GetDatum(HeapTupleHeaderGetXmin(tuphdr));
+			values[4] = UInt32GetDatum(HeapTupleHeaderGetRawXmin(tuphdr));
 			values[5] = UInt32GetDatum(HeapTupleHeaderGetRawXmax(tuphdr));
 			values[6] = UInt32GetDatum(HeapTupleHeaderGetRawCommandId(tuphdr)); /* shared with xvac */
 			values[7] = PointerGetDatum(&tuphdr->t_ctid);
diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index e39b9770cbf519cd65630f0332e92c004d4d4f7d..347d6163d3e5a5a3e5fd459ca03e9c38d0a9c648 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -539,7 +539,7 @@ heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
 			result = ObjectIdGetDatum(HeapTupleGetOid(tup));
 			break;
 		case MinTransactionIdAttributeNumber:
-			result = TransactionIdGetDatum(HeapTupleHeaderGetXmin(tup->t_data));
+			result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmin(tup->t_data));
 			break;
 		case MaxTransactionIdAttributeNumber:
 			result = TransactionIdGetDatum(HeapTupleHeaderGetRawXmax(tup->t_data));
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 4dfc8b1de50fa938586e6003948d2cb9ae7403f3..f8545c1eb702de90df52e9cd4245440ad4a4e204 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2257,13 +2257,10 @@ heap_prepare_insert(Relation relation, HeapTuple tup, TransactionId xid,
 	tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
 	tup->t_data->t_infomask2 &= ~(HEAP2_XACT_MASK);
 	tup->t_data->t_infomask |= HEAP_XMAX_INVALID;
+	HeapTupleHeaderSetXmin(tup->t_data, xid);
 	if (options & HEAP_INSERT_FROZEN)
-	{
-		tup->t_data->t_infomask |= HEAP_XMIN_COMMITTED;
-		HeapTupleHeaderSetXmin(tup->t_data, FrozenTransactionId);
-	}
-	else
-		HeapTupleHeaderSetXmin(tup->t_data, xid);
+		HeapTupleHeaderSetXminFrozen(tup->t_data);
+
 	HeapTupleHeaderSetCmin(tup->t_data, cid);
 	HeapTupleHeaderSetXmax(tup->t_data, 0);		/* for cleanliness */
 	tup->t_tableOid = RelationGetRelid(relation);
@@ -5732,13 +5729,7 @@ heap_prepare_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
 	if (TransactionIdIsNormal(xid) &&
 		TransactionIdPrecedes(xid, cutoff_xid))
 	{
-		frz->frzflags |= XLH_FREEZE_XMIN;
-
-		/*
-		 * Might as well fix the hint bits too; usually XMIN_COMMITTED will
-		 * already be set here, but there's a small chance not.
-		 */
-		frz->t_infomask |= HEAP_XMIN_COMMITTED;
+		frz->t_infomask |= HEAP_XMIN_FROZEN;
 		changed = true;
 	}
 
@@ -5882,9 +5873,6 @@ heap_prepare_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
 void
 heap_execute_freeze_tuple(HeapTupleHeader tuple, xl_heap_freeze_tuple *frz)
 {
-	if (frz->frzflags & XLH_FREEZE_XMIN)
-		HeapTupleHeaderSetXmin(tuple, FrozenTransactionId);
-
 	HeapTupleHeaderSetXmax(tuple, frz->xmax);
 
 	if (frz->frzflags & XLH_FREEZE_XVAC)
@@ -6361,10 +6349,8 @@ HeapTupleHeaderAdvanceLatestRemovedXid(HeapTupleHeader tuple,
 	 * This needs to work on both master and standby, where it is used to
 	 * assess btree delete records.
 	 */
-	if ((tuple->t_infomask & HEAP_XMIN_COMMITTED) ||
-		(!(tuple->t_infomask & HEAP_XMIN_COMMITTED) &&
-		 !(tuple->t_infomask & HEAP_XMIN_INVALID) &&
-		 TransactionIdDidCommit(xmin)))
+	if (HeapTupleHeaderXminCommitted(tuple) ||
+		(!HeapTupleHeaderXminInvalid(tuple) && TransactionIdDidCommit(xmin)))
 	{
 		if (xmax != xmin &&
 			TransactionIdFollows(xmax, *latestRemovedXid))
@@ -6882,7 +6868,7 @@ log_heap_new_cid(Relation relation, HeapTuple tup)
 	if (hdr->t_infomask & HEAP_COMBOCID)
 	{
 		Assert(!(hdr->t_infomask & HEAP_XMAX_INVALID));
-		Assert(!(hdr->t_infomask & HEAP_XMIN_INVALID));
+		Assert(!HeapTupleHeaderXminInvalid(hdr));
 		xlrec.cmin = HeapTupleHeaderGetCmin(hdr);
 		xlrec.cmax = HeapTupleHeaderGetCmax(hdr);
 		xlrec.combocid = HeapTupleHeaderGetRawCommandId(hdr);
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index b6fb2e31c5954bbfc1043c624962e6f2482983e0..888a400a03f6b3659bcf3cfb629645a6b5a6aecb 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -361,10 +361,10 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 		item = PageGetItem((Page) page, itemId);
 
 		HeapTupleHeaderSetXmin((HeapTupleHeader) item, FrozenTransactionId);
-		((HeapTupleHeader) item)->t_infomask |= HEAP_XMIN_COMMITTED;
+		HeapTupleHeaderSetXminFrozen((HeapTupleHeader) item);
 
 		HeapTupleHeaderSetXmin(tuple->t_data, FrozenTransactionId);
-		tuple->t_data->t_infomask |= HEAP_XMIN_COMMITTED;
+		HeapTupleHeaderSetXminFrozen(tuple->t_data);
 	}
 
 	MarkBufferDirty(buf);
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 8dd3de5e8e2984e09b9f025ce3612df60bcb50a5..878f0d28ccbda6110532e76a79b2ee293f8f5e6f 100644
--- a/src/backend/commands/vacuumlazy.c
+++ b/src/backend/commands/vacuumlazy.c
@@ -823,14 +823,14 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats,
 					 * NB: Like with per-tuple hint bits, we can't set the
 					 * PD_ALL_VISIBLE flag if the inserter committed
 					 * asynchronously. See SetHintBits for more info. Check
-					 * that the HEAP_XMIN_COMMITTED hint bit is set because of
-					 * that.
+					 * that the tuple is hinted xmin-committed because
+					 * of that.
 					 */
 					if (all_visible)
 					{
 						TransactionId xmin;
 
-						if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
+						if (!HeapTupleHeaderXminCommitted(tuple.t_data))
 						{
 							all_visible = false;
 							break;
@@ -1774,7 +1774,7 @@ heap_page_is_all_visible(Relation rel, Buffer buf, TransactionId *visibility_cut
 					TransactionId xmin;
 
 					/* Check comments in lazy_scan_heap. */
-					if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
+					if (!HeapTupleHeaderXminCommitted(tuple.t_data))
 					{
 						all_visible = false;
 						break;
diff --git a/src/backend/storage/buffer/README b/src/backend/storage/buffer/README
index 6fd961206b5026d0d6c60eaf0652895b33b63068..80443348c6062ec6b38391b1ffd7eaf4f7b39c08 100644
--- a/src/backend/storage/buffer/README
+++ b/src/backend/storage/buffer/README
@@ -65,6 +65,9 @@ manage to be a conflict it would merely mean that one bit-update would
 be lost and need to be done again later.  These four bits are only hints
 (they cache the results of transaction status lookups in pg_clog), so no
 great harm is done if they get reset to zero by conflicting updates.
+Note, however, that a tuple is frozen by setting both HEAP_XMIN_INVALID
+and HEAP_XMIN_COMMITTED; this is a critical update and accordingly requires
+an exclusive buffer lock (and it must also be WAL-logged).
 
 5. To physically remove a tuple or compact free space on a page, one
 must hold a pin and an exclusive lock, *and* observe while holding the
diff --git a/src/backend/utils/fmgr/fmgr.c b/src/backend/utils/fmgr/fmgr.c
index 9246a00cbae192a760e44ba5ad9b8e1f7f50a482..cae111646450764fa6f13a2b0ccea9674d77faa6 100644
--- a/src/backend/utils/fmgr/fmgr.c
+++ b/src/backend/utils/fmgr/fmgr.c
@@ -514,7 +514,7 @@ lookup_C_func(HeapTuple procedureTuple)
 					NULL);
 	if (entry == NULL)
 		return NULL;			/* no such entry */
-	if (entry->fn_xmin == HeapTupleHeaderGetXmin(procedureTuple->t_data) &&
+	if (entry->fn_xmin == HeapTupleHeaderGetRawXmin(procedureTuple->t_data) &&
 		ItemPointerEquals(&entry->fn_tid, &procedureTuple->t_self))
 		return entry;			/* OK */
 	return NULL;				/* entry is out of date */
@@ -552,7 +552,7 @@ record_C_func(HeapTuple procedureTuple,
 					HASH_ENTER,
 					&found);
 	/* OID is already filled in */
-	entry->fn_xmin = HeapTupleHeaderGetXmin(procedureTuple->t_data);
+	entry->fn_xmin = HeapTupleHeaderGetRawXmin(procedureTuple->t_data);
 	entry->fn_tid = procedureTuple->t_self;
 	entry->user_fn = user_fn;
 	entry->inforec = inforec;
diff --git a/src/backend/utils/time/combocid.c b/src/backend/utils/time/combocid.c
index 923355d3ceb4f3e49a584ab3c420c7b31b0272ae..64e68eb3aae6d9b3301d404d75cb131d2c8a6313 100644
--- a/src/backend/utils/time/combocid.c
+++ b/src/backend/utils/time/combocid.c
@@ -148,11 +148,11 @@ HeapTupleHeaderAdjustCmax(HeapTupleHeader tup,
 	/*
 	 * If we're marking a tuple deleted that was inserted by (any
 	 * subtransaction of) our transaction, we need to use a combo command id.
-	 * Test for HEAP_XMIN_COMMITTED first, because it's cheaper than a
+	 * Test for HeapTupleHeaderXminCommitted() first, because it's cheaper than a
 	 * TransactionIdIsCurrentTransactionId call.
 	 */
-	if (!(tup->t_infomask & HEAP_XMIN_COMMITTED) &&
-		TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tup)))
+	if (!HeapTupleHeaderXminCommitted(tup) &&
+		TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetRawXmin(tup)))
 	{
 		CommandId	cmin = HeapTupleHeaderGetCmin(tup);
 
diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c
index 1ff1da2f07607a35920877aec2281c8a5cfa8ed0..8bd0ac01f68e285790b1583c090c0cf72a8681d7 100644
--- a/src/backend/utils/time/tqual.c
+++ b/src/backend/utils/time/tqual.c
@@ -166,9 +166,9 @@ HeapTupleSatisfiesSelf(HeapTuple htup, Snapshot snapshot, Buffer buffer)
 	Assert(ItemPointerIsValid(&htup->t_self));
 	Assert(htup->t_tableOid != InvalidOid);
 
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return false;
 
 		/* Used by pre-9.0 binary upgrades */
@@ -210,7 +210,7 @@ HeapTupleSatisfiesSelf(HeapTuple htup, Snapshot snapshot, Buffer buffer)
 				}
 			}
 		}
-		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetRawXmin(tuple)))
 		{
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
 				return true;
@@ -244,11 +244,11 @@ HeapTupleSatisfiesSelf(HeapTuple htup, Snapshot snapshot, Buffer buffer)
 
 			return false;
 		}
-		else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsInProgress(HeapTupleHeaderGetRawXmin(tuple)))
 			return false;
-		else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdDidCommit(HeapTupleHeaderGetRawXmin(tuple)))
 			SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
-						HeapTupleHeaderGetXmin(tuple));
+						HeapTupleHeaderGetRawXmin(tuple));
 		else
 		{
 			/* it must have aborted or crashed */
@@ -356,9 +356,9 @@ HeapTupleSatisfiesToast(HeapTuple htup, Snapshot snapshot,
 	Assert(ItemPointerIsValid(&htup->t_self));
 	Assert(htup->t_tableOid != InvalidOid);
 
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return false;
 
 		/* Used by pre-9.0 binary upgrades */
@@ -441,9 +441,9 @@ HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
 	Assert(ItemPointerIsValid(&htup->t_self));
 	Assert(htup->t_tableOid != InvalidOid);
 
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return HeapTupleInvisible;
 
 		/* Used by pre-9.0 binary upgrades */
@@ -485,7 +485,7 @@ HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
 				}
 			}
 		}
-		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetRawXmin(tuple)))
 		{
 			if (HeapTupleHeaderGetCmin(tuple) >= curcid)
 				return HeapTupleInvisible;		/* inserted after scan started */
@@ -564,11 +564,11 @@ HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
 			else
 				return HeapTupleInvisible;		/* updated before scan started */
 		}
-		else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsInProgress(HeapTupleHeaderGetRawXmin(tuple)))
 			return HeapTupleInvisible;
-		else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdDidCommit(HeapTupleHeaderGetRawXmin(tuple)))
 			SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
-						HeapTupleHeaderGetXmin(tuple));
+						HeapTupleHeaderGetRawXmin(tuple));
 		else
 		{
 			/* it must have aborted or crashed */
@@ -715,9 +715,9 @@ HeapTupleSatisfiesDirty(HeapTuple htup, Snapshot snapshot,
 
 	snapshot->xmin = snapshot->xmax = InvalidTransactionId;
 
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return false;
 
 		/* Used by pre-9.0 binary upgrades */
@@ -759,7 +759,7 @@ HeapTupleSatisfiesDirty(HeapTuple htup, Snapshot snapshot,
 				}
 			}
 		}
-		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetRawXmin(tuple)))
 		{
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
 				return true;
@@ -793,15 +793,15 @@ HeapTupleSatisfiesDirty(HeapTuple htup, Snapshot snapshot,
 
 			return false;
 		}
-		else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsInProgress(HeapTupleHeaderGetRawXmin(tuple)))
 		{
-			snapshot->xmin = HeapTupleHeaderGetXmin(tuple);
+			snapshot->xmin = HeapTupleHeaderGetRawXmin(tuple);
 			/* XXX shouldn't we fall through to look at xmax? */
 			return true;		/* in insertion by other */
 		}
-		else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdDidCommit(HeapTupleHeaderGetRawXmin(tuple)))
 			SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
-						HeapTupleHeaderGetXmin(tuple));
+						HeapTupleHeaderGetRawXmin(tuple));
 		else
 		{
 			/* it must have aborted or crashed */
@@ -909,9 +909,9 @@ HeapTupleSatisfiesMVCC(HeapTuple htup, Snapshot snapshot,
 	Assert(ItemPointerIsValid(&htup->t_self));
 	Assert(htup->t_tableOid != InvalidOid);
 
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return false;
 
 		/* Used by pre-9.0 binary upgrades */
@@ -953,7 +953,7 @@ HeapTupleSatisfiesMVCC(HeapTuple htup, Snapshot snapshot,
 				}
 			}
 		}
-		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetRawXmin(tuple)))
 		{
 			if (HeapTupleHeaderGetCmin(tuple) >= snapshot->curcid)
 				return false;	/* inserted after scan started */
@@ -995,11 +995,11 @@ HeapTupleSatisfiesMVCC(HeapTuple htup, Snapshot snapshot,
 			else
 				return false;	/* deleted before scan started */
 		}
-		else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsInProgress(HeapTupleHeaderGetRawXmin(tuple)))
 			return false;
-		else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdDidCommit(HeapTupleHeaderGetRawXmin(tuple)))
 			SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
-						HeapTupleHeaderGetXmin(tuple));
+						HeapTupleHeaderGetRawXmin(tuple));
 		else
 		{
 			/* it must have aborted or crashed */
@@ -1013,7 +1013,8 @@ HeapTupleSatisfiesMVCC(HeapTuple htup, Snapshot snapshot,
 	 * By here, the inserting transaction has committed - have to check
 	 * when...
 	 */
-	if (XidInMVCCSnapshot(HeapTupleHeaderGetXmin(tuple), snapshot))
+	if (!HeapTupleHeaderXminFrozen(tuple)
+		&& XidInMVCCSnapshot(HeapTupleHeaderGetRawXmin(tuple), snapshot))
 		return false;			/* treat as still in progress */
 
 	if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid or aborted */
@@ -1116,9 +1117,9 @@ HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
 	 * If the inserting transaction aborted, then the tuple was never visible
 	 * to any other transaction, so we can delete it immediately.
 	 */
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
+	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
-		if (tuple->t_infomask & HEAP_XMIN_INVALID)
+		if (HeapTupleHeaderXminInvalid(tuple))
 			return HEAPTUPLE_DEAD;
 		/* Used by pre-9.0 binary upgrades */
 		else if (tuple->t_infomask & HEAP_MOVED_OFF)
@@ -1157,7 +1158,7 @@ HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
 				return HEAPTUPLE_DEAD;
 			}
 		}
-		else if (TransactionIdIsInProgress(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdIsInProgress(HeapTupleHeaderGetRawXmin(tuple)))
 		{
 			if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
 				return HEAPTUPLE_INSERT_IN_PROGRESS;
@@ -1168,9 +1169,9 @@ HeapTupleSatisfiesVacuum(HeapTuple htup, TransactionId OldestXmin,
 			/* inserted and then deleted by same xact */
 			return HEAPTUPLE_DELETE_IN_PROGRESS;
 		}
-		else if (TransactionIdDidCommit(HeapTupleHeaderGetXmin(tuple)))
+		else if (TransactionIdDidCommit(HeapTupleHeaderGetRawXmin(tuple)))
 			SetHintBits(tuple, buffer, HEAP_XMIN_COMMITTED,
-						HeapTupleHeaderGetXmin(tuple));
+						HeapTupleHeaderGetRawXmin(tuple));
 		else
 		{
 			/*
@@ -1347,8 +1348,8 @@ HeapTupleIsSurelyDead(HeapTuple htup, TransactionId OldestXmin)
 	 * invalid, then we assume it's still alive (since the presumption is that
 	 * all relevant hint bits were just set moments ago).
 	 */
-	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
-		return (tuple->t_infomask & HEAP_XMIN_INVALID) != 0 ? true : false;
+	if (!HeapTupleHeaderXminCommitted(tuple))
+		return HeapTupleHeaderXminInvalid(tuple) ? true : false;
 
 	/*
 	 * If the inserting transaction committed, but any deleting transaction
diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h
index 4062b422a7d77dff6e1c616eb5b2a9a649c5d92f..0c37c42be8df8fefc26fb2eb4ed43e0166c9c99e 100644
--- a/src/include/access/heapam_xlog.h
+++ b/src/include/access/heapam_xlog.h
@@ -274,7 +274,7 @@ typedef struct xl_heap_inplace
  * This struct represents a 'freeze plan', which is what we need to know about
  * a single tuple being frozen during vacuum.
  */
-#define		XLH_FREEZE_XMIN		0x01
+/* 0x01 was XLH_FREEZE_XMIN */
 #define		XLH_FREEZE_XVAC		0x02
 #define		XLH_INVALID_XVAC	0x04
 
diff --git a/src/include/access/htup_details.h b/src/include/access/htup_details.h
index 0a832e915078a35296210cdf24cab4303b711877..c53305ffcda6344d5242b1696d4bde21cf30974d 100644
--- a/src/include/access/htup_details.h
+++ b/src/include/access/htup_details.h
@@ -17,6 +17,7 @@
 #include "access/htup.h"
 #include "access/tupdesc.h"
 #include "access/tupmacs.h"
+#include "access/transam.h"
 #include "storage/bufpage.h"
 
 /*
@@ -175,6 +176,7 @@ struct HeapTupleHeaderData
 						 HEAP_XMAX_KEYSHR_LOCK)
 #define HEAP_XMIN_COMMITTED		0x0100	/* t_xmin committed */
 #define HEAP_XMIN_INVALID		0x0200	/* t_xmin invalid/aborted */
+#define HEAP_XMIN_FROZEN		(HEAP_XMIN_COMMITTED|HEAP_XMIN_INVALID)
 #define HEAP_XMAX_COMMITTED		0x0400	/* t_xmax committed */
 #define HEAP_XMAX_INVALID		0x0800	/* t_xmax invalid/aborted */
 #define HEAP_XMAX_IS_MULTI		0x1000	/* t_xmax is a MultiXactId */
@@ -244,16 +246,64 @@ struct HeapTupleHeaderData
  * macros evaluate their other argument only once.
  */
 
-#define HeapTupleHeaderGetXmin(tup) \
+/*
+ * HeapTupleHeaderGetRawXmin returns the "raw" xmin field, which is the xid
+ * originally used to insert the tuple.  However, the tuple might actually
+ * be frozen (via HeapTupleHeaderSetXminFrozen) in which case the tuple's xmin
+ * is visible to every snapshot.  Prior to PostgreSQL 9.4, we actually changed
+ * the xmin to FrozenTransactionId, and that value may still be encountered
+ * on disk.
+ */
+#define HeapTupleHeaderGetRawXmin(tup) \
 ( \
 	(tup)->t_choice.t_heap.t_xmin \
 )
 
+#define HeapTupleHeaderGetXmin(tup) \
+( \
+	HeapTupleHeaderXminFrozen(tup) ? \
+		FrozenTransactionId : HeapTupleHeaderGetRawXmin(tup) \
+)
+
 #define HeapTupleHeaderSetXmin(tup, xid) \
 ( \
 	(tup)->t_choice.t_heap.t_xmin = (xid) \
 )
 
+#define HeapTupleHeaderXminCommitted(tup) \
+( \
+	(tup)->t_infomask & HEAP_XMIN_COMMITTED \
+)
+
+#define HeapTupleHeaderXminInvalid(tup) \
+( \
+	((tup)->t_infomask & (HEAP_XMIN_COMMITTED|HEAP_XMIN_INVALID)) == \
+		HEAP_XMIN_INVALID \
+)
+
+#define HeapTupleHeaderXminFrozen(tup) \
+( \
+	((tup)->t_infomask & (HEAP_XMIN_FROZEN)) == HEAP_XMIN_FROZEN \
+)
+
+#define HeapTupleHeaderSetXminCommitted(tup) \
+( \
+	AssertMacro(!HeapTupleHeaderXminInvalid(tup)), \
+	((tup)->t_infomask |= HEAP_XMIN_COMMITTED) \
+)
+
+#define HeapTupleHeaderSetXminInvalid(tup) \
+( \
+	AssertMacro(!HeapTupleHeaderXminCommitted(tup)), \
+	((tup)->t_infomask |= HEAP_XMIN_INVALID) \
+)
+
+#define HeapTupleHeaderSetXminFrozen(tup) \
+( \
+	AssertMacro(!HeapTupleHeaderXminInvalid(tup)), \
+	((tup)->t_infomask |= HEAP_XMIN_FROZEN) \
+)
+
 /*
  * HeapTupleHeaderGetRawXmax gets you the raw Xmax field.  To find out the Xid
  * that updated a tuple, you might need to resolve the MultiXactId if certain
@@ -374,7 +424,8 @@ do { \
 #define HeapTupleHeaderIsHotUpdated(tup) \
 ( \
 	((tup)->t_infomask2 & HEAP_HOT_UPDATED) != 0 && \
-	((tup)->t_infomask & (HEAP_XMIN_INVALID | HEAP_XMAX_INVALID)) == 0 \
+	((tup)->t_infomask & HEAP_XMAX_INVALID) == 0 && \
+	!HeapTupleHeaderXminInvalid(tup) \
 )
 
 #define HeapTupleHeaderSetHotUpdated(tup) \
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index c301d5e5d65b8d5bcda90b45a394add8e26d05d8..1f791826ae8793798c771c87840bc4d93eb8a796 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -55,7 +55,7 @@ typedef struct BkpBlock
 /*
  * Each page of XLOG file has a header like this:
  */
-#define XLOG_PAGE_MAGIC 0xD07A	/* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD07B	/* can be used as WAL version indicator */
 
 typedef struct XLogPageHeaderData
 {
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 4f5b92fa3affbf77b7308dc8ea88cfbb1ca84631..a81c18513e506b326e1aa36fb384149cee7b80b7 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -2524,7 +2524,7 @@ validate_plperl_function(plperl_proc_ptr *proc_ptr, HeapTuple procTup)
 		 * This is needed because CREATE OR REPLACE FUNCTION can modify the
 		 * function's pg_proc entry without changing its OID.
 		 ************************************************************/
-		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
+		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
 					ItemPointerEquals(&prodesc->fn_tid, &procTup->t_self));
 
 		if (uptodate)
@@ -2642,7 +2642,7 @@ compile_plperl_function(Oid fn_oid, bool is_trigger, bool is_event_trigger)
 					(errcode(ERRCODE_OUT_OF_MEMORY),
 					 errmsg("out of memory")));
 		}
-		prodesc->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
+		prodesc->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
 		prodesc->fn_tid = procTup->t_self;
 
 		/* Remember if function is STABLE/IMMUTABLE */
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 426aeb53f5888c1c1f7348ca4aaabda1925dc18d..9a16b0d4d19401abbf03cb719a29de96f9953d6e 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -167,7 +167,7 @@ recheck:
 	if (function)
 	{
 		/* We have a compiled function, but is it still valid? */
-		if (function->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
+		if (function->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
 			ItemPointerEquals(&function->fn_tid, &procTup->t_self))
 			function_valid = true;
 		else
@@ -345,7 +345,7 @@ do_compile(FunctionCallInfo fcinfo,
 
 	function->fn_signature = format_procedure(fcinfo->flinfo->fn_oid);
 	function->fn_oid = fcinfo->flinfo->fn_oid;
-	function->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
+	function->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
 	function->fn_tid = procTup->t_self;
 	function->fn_input_collation = fcinfo->fncollation;
 	function->fn_cxt = func_cxt;
diff --git a/src/pl/plpython/plpy_procedure.c b/src/pl/plpython/plpy_procedure.c
index d278d6e7058c41ec49dffd4a57135ebb8dd895b6..fad80b242e75a9a11a2e8214d6b08695bfc30216 100644
--- a/src/pl/plpython/plpy_procedure.c
+++ b/src/pl/plpython/plpy_procedure.c
@@ -157,7 +157,7 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
 	proc = PLy_malloc(sizeof(PLyProcedure));
 	proc->proname = PLy_strdup(NameStr(procStruct->proname));
 	proc->pyname = PLy_strdup(procName);
-	proc->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
+	proc->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
 	proc->fn_tid = procTup->t_self;
 	/* Remember if function is STABLE/IMMUTABLE */
 	proc->fn_readonly =
@@ -446,7 +446,7 @@ PLy_procedure_argument_valid(PLyTypeInfo *arg)
 		elog(ERROR, "cache lookup failed for relation %u", arg->typ_relid);
 
 	/* If it has changed, the cached data is not valid */
-	valid = (arg->typrel_xmin == HeapTupleHeaderGetXmin(relTup->t_data) &&
+	valid = (arg->typrel_xmin == HeapTupleHeaderGetRawXmin(relTup->t_data) &&
 			 ItemPointerEquals(&arg->typrel_tid, &relTup->t_self));
 
 	ReleaseSysCache(relTup);
@@ -466,7 +466,7 @@ PLy_procedure_valid(PLyProcedure *proc, HeapTuple procTup)
 	Assert(proc != NULL);
 
 	/* If the pg_proc tuple has changed, it's not valid */
-	if (!(proc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
+	if (!(proc->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
 		  ItemPointerEquals(&proc->fn_tid, &procTup->t_self)))
 		return false;
 
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index 0a2307abdb98306a703b9b343f52e08126c87de7..7a5e581280d9b39cb1fb3515ece0fb0722cd1ff1 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -157,7 +157,7 @@ PLy_input_tuple_funcs(PLyTypeInfo *arg, TupleDesc desc)
 			elog(ERROR, "cache lookup failed for relation %u", arg->typ_relid);
 
 		/* Remember XMIN and TID for later validation if cache is still OK */
-		arg->typrel_xmin = HeapTupleHeaderGetXmin(relTup->t_data);
+		arg->typrel_xmin = HeapTupleHeaderGetRawXmin(relTup->t_data);
 		arg->typrel_tid = relTup->t_self;
 
 		ReleaseSysCache(relTup);
@@ -221,7 +221,7 @@ PLy_output_tuple_funcs(PLyTypeInfo *arg, TupleDesc desc)
 			elog(ERROR, "cache lookup failed for relation %u", arg->typ_relid);
 
 		/* Remember XMIN and TID for later validation if cache is still OK */
-		arg->typrel_xmin = HeapTupleHeaderGetXmin(relTup->t_data);
+		arg->typrel_xmin = HeapTupleHeaderGetRawXmin(relTup->t_data);
 		arg->typrel_tid = relTup->t_self;
 
 		ReleaseSysCache(relTup);
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 9b801b153a193a08ad8cc0f8641bf8c5ebd7b8e7..053803898215e6740c39b6342363f9e8399807cd 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -1257,7 +1257,7 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
 	{
 		bool		uptodate;
 
-		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
+		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
 					ItemPointerEquals(&prodesc->fn_tid, &procTup->t_self));
 
 		if (!uptodate)
@@ -1322,7 +1322,7 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
 			ereport(ERROR,
 					(errcode(ERRCODE_OUT_OF_MEMORY),
 					 errmsg("out of memory")));
-		prodesc->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
+		prodesc->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
 		prodesc->fn_tid = procTup->t_self;
 
 		/* Remember if function is STABLE/IMMUTABLE */