Replace XLogRecPtr struct with a 64-bit integer.

This simplifies code that needs to do arithmetic on XLogRecPtrs. To avoid changing on-disk format of data pages, the LSN on data pages is still stored in the old format. That should keep pg_upgrade happy. However, we have XLogRecPtrs embedded in the control file, and in the structs that are sent over the replication protocol, so this changes breaks compatibility of pg_basebackup and server. I didn't do anything about this in this patch, per discussion on -hackers, the right thing to do would to be to change the replication protocol to be architecture-independent, so that you could use a newer version of pg_receivexlog, for example, against an older server version.
14 years ago · 0ab9d1c4b3
parent 061e7efb1b
commit 0ab9d1c4b3
28 changed files with 280 additions and 358 deletions
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@ -206,7 +206,8 @@ page_header(PG_FUNCTION_ARGS)
 	/* Extract information from the page header */

 	lsn = PageGetLSN(page);
-	snprintf(lsnchar, sizeof(lsnchar), "%X/%X", lsn.xlogid, lsn.xrecoff);
+	snprintf(lsnchar, sizeof(lsnchar), "%X/%X",
+			 (uint32) (lsn >> 32), (uint32) lsn);

 	values[0] = CStringGetTextDatum(lsnchar);
 	values[1] = UInt16GetDatum(PageGetTLI(page));
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@ -197,7 +197,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		SplitedPageLayout *dist = NULL,
 				   *ptr;
 		BlockNumber oldrlink = InvalidBlockNumber;
-		GistNSN		oldnsn = {0, 0};
+		GistNSN		oldnsn = 0;
 		SplitedPageLayout rootpg;
 		BlockNumber blkno = BufferGetBlockNumber(buffer);
 		bool		is_rootsplit;
@ -488,7 +488,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)

 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
-	firststack.lsn.xrecoff = 0;
+	firststack.lsn = 0;
 	firststack.parent = NULL;
 	firststack.downlinkoffnum = InvalidOffsetNumber;
 	state.stack = stack = &firststack;
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@ -706,13 +706,7 @@ gistoptions(PG_FUNCTION_ARGS)
 XLogRecPtr
 GetXLogRecPtrForTemp(void)
 {
-	static XLogRecPtr counter = {0, 1};
-
-	counter.xrecoff++;
-	if (counter.xrecoff == 0)
-	{
-		counter.xlogid++;
-		counter.xrecoff++;
-	}
+	static XLogRecPtr counter = 1;
+	counter++;
 	return counter;
 }
--- a/src/backend/access/transam/transam.c
+++ b/src/backend/access/transam/transam.c
@ -24,9 +24,6 @@
 #include "access/transam.h"
 #include "utils/snapmgr.h"

-/* Handy constant for an invalid xlog recptr */
-const XLogRecPtr InvalidXLogRecPtr = {0, 0};
-
 /*
 * Single-item cache for results of TransactionLogFetch.  It's worth having
 * such a cache because we frequently find ourselves repeatedly checking the
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@ -333,8 +333,7 @@ MarkAsPreparing(TransactionId xid, const char *gid,

 	gxact->prepared_at = prepared_at;
 	/* initialize LSN to 0 (start of WAL) */
-	gxact->prepare_lsn.xlogid = 0;
-	gxact->prepare_lsn.xrecoff = 0;
+	gxact->prepare_lsn = 0;
 	gxact->owner = owner;
 	gxact->locking_xid = xid;
 	gxact->valid = false;
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@ -951,7 +951,7 @@ RecordTransactionCommit(void)
 	if (XLogStandbyInfoActive())
 		nmsgs = xactGetCommittedInvalidationMessages(&invalMessages,
 													 &RelcacheInitFileInval);
-	wrote_xlog = (XactLastRecEnd.xrecoff != 0);
+	wrote_xlog = (XactLastRecEnd != 0);

 	/*
 	 * If we haven't been assigned an XID yet, we neither can, nor do we want
@ -1200,7 +1200,7 @@ RecordTransactionCommit(void)
 		SyncRepWaitForLSN(XactLastRecEnd);

 	/* Reset XactLastRecEnd until the next transaction writes something */
-	XactLastRecEnd.xrecoff = 0;
+	XactLastRecEnd = 0;

 cleanup:
 	/* Clean up local data */
@ -1402,7 +1402,7 @@ RecordTransactionAbort(bool isSubXact)
 	{
 		/* Reset XactLastRecEnd until the next transaction writes something */
 		if (!isSubXact)
-			XactLastRecEnd.xrecoff = 0;
+			XactLastRecEnd = 0;
 		return InvalidTransactionId;
 	}

@ -1501,7 +1501,7 @@ RecordTransactionAbort(bool isSubXact)

 	/* Reset XactLastRecEnd until the next transaction writes something */
 	if (!isSubXact)
-		XactLastRecEnd.xrecoff = 0;
+		XactLastRecEnd = 0;

 	/* And clean up local data */
 	if (rels)
@ -2170,7 +2170,7 @@ PrepareTransaction(void)
 	 */

 	/* Reset XactLastRecEnd until the next transaction writes something */
-	XactLastRecEnd.xrecoff = 0;
+	XactLastRecEnd = 0;

 	/*
 	 * Let others know about no transaction in progress by me.	This has to be
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@ -252,9 +252,9 @@ static TimeLineID curFileTLI;
 * or start a new one; so it can be used to tell if the current transaction has
 * created any XLOG records.
 */
-static XLogRecPtr ProcLastRecPtr = {0, 0};
+static XLogRecPtr ProcLastRecPtr = InvalidXLogRecPtr;

-XLogRecPtr	XactLastRecEnd = {0, 0};
+XLogRecPtr	XactLastRecEnd = InvalidXLogRecPtr;

 /*
 * RedoRecPtr is this backend's local copy of the REDO record pointer
@ -278,7 +278,7 @@ static XLogRecPtr RedoRecPtr;
 * backwards to the REDO location after reading the checkpoint record,
 * because the REDO record can precede the checkpoint record.
 */
-static XLogRecPtr RedoStartLSN = {0, 0};
+static XLogRecPtr RedoStartLSN = InvalidXLogRecPtr;

 /*----------
 * Shared-memory data structures for XLOG control
@ -493,13 +493,7 @@ static ControlFileData *ControlFile = NULL;

 /* Construct XLogRecPtr value for current insertion point */
 #define INSERT_RECPTR(recptr,Insert,curridx)  \
-	do {																\
-		(recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid;			\
-		(recptr).xrecoff =												\
-			XLogCtl->xlblocks[curridx].xrecoff - INSERT_FREESPACE(Insert); \
-		if (XLogCtl->xlblocks[curridx].xrecoff == 0)					\
-			(recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid - 1;	\
-	} while(0)
+		(recptr) = XLogCtl->xlblocks[curridx] - INSERT_FREESPACE(Insert)

 #define PrevBufIdx(idx)		\
 		(((idx) == 0) ? XLogCtl->XLogCacheBlck : ((idx) - 1))
@ -511,7 +505,7 @@ static ControlFileData *ControlFile = NULL;
 * Private, possibly out-of-date copy of shared LogwrtResult.
 * See discussion above.
 */
-static XLogwrtResult LogwrtResult = {{0, 0}, {0, 0}};
+static XLogwrtResult LogwrtResult = {0, 0};

 /*
 * Codes indicating where we got a WAL file from during recovery, or where
@ -745,8 +739,7 @@ XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata)
 	 */
 	if (IsBootstrapProcessingMode() && rmid != RM_XLOG_ID)
 	{
-		RecPtr.xlogid = 0;
-		RecPtr.xrecoff = SizeOfXLogLongPHD;		/* start of 1st chkpt record */
+		RecPtr = SizeOfXLogLongPHD;		/* start of 1st chkpt record */
 		return RecPtr;
 	}

@ -1011,13 +1004,12 @@ begin:;
 	 * everything is written and flushed through the end of the prior segment,
 	 * and return the prior segment's end address.
 	 */
-	if (isLogSwitch &&
-		(RecPtr.xrecoff % XLogSegSize) == SizeOfXLogLongPHD)
+	if (isLogSwitch && (RecPtr % XLogSegSize) == SizeOfXLogLongPHD)
 	{
 		/* We can release insert lock immediately */
 		LWLockRelease(WALInsertLock);

-		RecPtr.xrecoff -= SizeOfXLogLongPHD;
+		RecPtr -= SizeOfXLogLongPHD;

 		LWLockAcquire(WALWriteLock, LW_EXCLUSIVE);
 		LogwrtResult = XLogCtl->LogwrtResult;
@ -1051,7 +1043,7 @@ begin:;

 		initStringInfo(&buf);
 		appendStringInfo(&buf, "INSERT @ %X/%X: ",
-						 RecPtr.xlogid, RecPtr.xrecoff);
+						 (uint32) (RecPtr >> 32), (uint32) RecPtr);
 		xlog_outrec(&buf, rechdr);
 		if (rdata->data != NULL)
 		{
@ -1152,12 +1144,7 @@ begin:;

 		/* Compute end address of old segment */
 		OldSegEnd = XLogCtl->xlblocks[curridx];
-		if (OldSegEnd.xrecoff == 0)
-		{
-			/* crossing a logid boundary */
-			OldSegEnd.xlogid -= 1;
-		}
-		OldSegEnd.xrecoff -= XLOG_BLCKSZ;
+		OldSegEnd -= XLOG_BLCKSZ;

 		/* Make it look like we've written and synced all of old segment */
 		LogwrtResult.Write = OldSegEnd;
@ -1523,8 +1510,7 @@ AdvanceXLInsertBuffer(bool new_segment)
 				 */
 				TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_START();
 				WriteRqst.Write = OldPageRqstPtr;
-				WriteRqst.Flush.xlogid = 0;
-				WriteRqst.Flush.xrecoff = 0;
+				WriteRqst.Flush = 0;
 				XLogWrite(WriteRqst, false, false);
 				LWLockRelease(WALWriteLock);
 				TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
@ -1541,9 +1527,9 @@ AdvanceXLInsertBuffer(bool new_segment)
 	if (new_segment)
 	{
 		/* force it to a segment start point */
-		if (NewPageBeginPtr.xrecoff % XLogSegSize != 0)
+		if (NewPageBeginPtr % XLogSegSize != 0)
 			XLByteAdvance(NewPageBeginPtr,
-						  XLogSegSize - NewPageBeginPtr.xrecoff % XLogSegSize);
+						  XLogSegSize - NewPageBeginPtr % XLogSegSize);
 	}

 	NewPageEndPtr = NewPageBeginPtr;
@ -1589,7 +1575,7 @@ AdvanceXLInsertBuffer(bool new_segment)
 	/*
 	 * If first page of an XLOG segment file, make it a long header.
 	 */
-	if ((NewPage->xlp_pageaddr.xrecoff % XLogSegSize) == 0)
+	if ((NewPage->xlp_pageaddr % XLogSegSize) == 0)
 	{
 		XLogLongPageHeader NewLongPage = (XLogLongPageHeader) NewPage;

@ -1693,9 +1679,9 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch)
 		 */
 		if (!XLByteLT(LogwrtResult.Write, XLogCtl->xlblocks[curridx]))
 			elog(PANIC, "xlog write request %X/%X is past end of log %X/%X",
-				 LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff,
-				 XLogCtl->xlblocks[curridx].xlogid,
-				 XLogCtl->xlblocks[curridx].xrecoff);
+				 (uint32) (LogwrtResult.Write >> 32), (uint32) LogwrtResult.Write,
+				 (uint32) (XLogCtl->xlblocks[curridx] >> 32),
+				 (uint32) XLogCtl->xlblocks[curridx]);

 		/* Advance LogwrtResult.Write to end of current buffer page */
 		LogwrtResult.Write = XLogCtl->xlblocks[curridx];
@ -1731,7 +1717,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch)
 		{
 			/* first of group */
 			startidx = curridx;
-			startoffset = (LogwrtResult.Write.xrecoff - XLOG_BLCKSZ) % XLogSegSize;
+			startoffset = (LogwrtResult.Write - XLOG_BLCKSZ) % XLogSegSize;
 		}
 		npages++;

@ -1923,7 +1909,7 @@ XLogSetAsyncXactLSN(XLogRecPtr asyncXactLSN)
 	if (!sleeping)
 	{
 		/* back off to last completed page boundary */
-		WriteRqstPtr.xrecoff -= WriteRqstPtr.xrecoff % XLOG_BLCKSZ;
+		WriteRqstPtr -= WriteRqstPtr % XLOG_BLCKSZ;

 		/* if we have already flushed that far, we're done */
 		if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush))
@ -1965,7 +1951,7 @@ UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force)
 	 * i.e., we're doing crash recovery.  We never modify the control file's
 	 * value in that case, so we can short-circuit future checks here too.
 	 */
-	if (minRecoveryPoint.xlogid == 0 && minRecoveryPoint.xrecoff == 0)
+	if (minRecoveryPoint == 0)
 		updateMinRecoveryPoint = false;
 	else if (force || XLByteLT(minRecoveryPoint, lsn))
 	{
@ -1993,8 +1979,9 @@ UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force)
 		if (!force && XLByteLT(newMinRecoveryPoint, lsn))
 			elog(WARNING,
 			   "xlog min recovery request %X/%X is past current point %X/%X",
-				 lsn.xlogid, lsn.xrecoff,
-				 newMinRecoveryPoint.xlogid, newMinRecoveryPoint.xrecoff);
+				 (uint32) (lsn >> 32) , (uint32) lsn,
+				 (uint32) (newMinRecoveryPoint >> 32),
+				 (uint32) newMinRecoveryPoint);

 		/* update control file */
 		if (XLByteLT(ControlFile->minRecoveryPoint, newMinRecoveryPoint))
@ -2005,7 +1992,8 @@ UpdateMinRecoveryPoint(XLogRecPtr lsn, bool force)

 			ereport(DEBUG2,
 					(errmsg("updated min recovery point to %X/%X",
-						minRecoveryPoint.xlogid, minRecoveryPoint.xrecoff)));
+							(uint32) (minRecoveryPoint >> 32),
+							(uint32) minRecoveryPoint)));
 		}
 	}
 	LWLockRelease(ControlFileLock);
@ -2043,9 +2031,9 @@ XLogFlush(XLogRecPtr record)
 #ifdef WAL_DEBUG
 	if (XLOG_DEBUG)
 		elog(LOG, "xlog flush request %X/%X; write %X/%X; flush %X/%X",
-			 record.xlogid, record.xrecoff,
-			 LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff,
-			 LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff);
+			 (uint32) (record >> 32), (uint32) record,
+			 (uint32) (LogwrtResult.Write >> 32), (uint32) LogwrtResult.Write,
+			 (uint32) (LogwrtResult.Flush >> 32), (uint32) LogwrtResult.Flush);
 #endif

 	START_CRIT_SECTION();
@ -2112,9 +2100,7 @@ XLogFlush(XLogRecPtr record)
 				else
 				{
 					WriteRqstPtr = XLogCtl->xlblocks[Insert->curridx];
-					if (WriteRqstPtr.xrecoff == 0)
-						WriteRqstPtr.xlogid--;
-					WriteRqstPtr.xrecoff -= freespace;
+					WriteRqstPtr -= freespace;
 				}
 				LWLockRelease(WALInsertLock);
 				WriteRqst.Write = WriteRqstPtr;
@ -2158,8 +2144,8 @@ XLogFlush(XLogRecPtr record)
 	if (XLByteLT(LogwrtResult.Flush, record))
 		elog(ERROR,
 		"xlog flush request %X/%X is not satisfied --- flushed only to %X/%X",
-			 record.xlogid, record.xrecoff,
-			 LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff);
+			 (uint32) (record >> 32), (uint32) record,
+			 (uint32) (LogwrtResult.Flush >> 32), (uint32) LogwrtResult.Flush);
 }

 /*
@ -2202,7 +2188,7 @@ XLogBackgroundFlush(void)
 	}

 	/* back off to last completed page boundary */
-	WriteRqstPtr.xrecoff -= WriteRqstPtr.xrecoff % XLOG_BLCKSZ;
+	WriteRqstPtr -= WriteRqstPtr % XLOG_BLCKSZ;

 	/* if we have already flushed that far, consider async commit records */
 	if (XLByteLE(WriteRqstPtr, LogwrtResult.Flush))
@ -2236,9 +2222,9 @@ XLogBackgroundFlush(void)
 #ifdef WAL_DEBUG
 	if (XLOG_DEBUG)
 		elog(LOG, "xlog bg flush request %X/%X; write %X/%X; flush %X/%X",
-			 WriteRqstPtr.xlogid, WriteRqstPtr.xrecoff,
-			 LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff,
-			 LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff);
+			 (uint32) (WriteRqstPtr >> 32), (uint32) WriteRqstPtr,
+			 (uint32) (LogwrtResult.Write >> 32), (uint32) LogwrtResult.Write,
+			 (uint32) (LogwrtResult.Flush >> 32), (uint32) LogwrtResult.Flush);
 #endif

 	START_CRIT_SECTION();
@ -2305,7 +2291,7 @@ XLogNeedsFlush(XLogRecPtr record)
 		 * file's value in that case, so we can short-circuit future checks
 		 * here too.
 		 */
-		if (minRecoveryPoint.xlogid == 0 && minRecoveryPoint.xrecoff == 0)
+		if (minRecoveryPoint == 0)
 			updateMinRecoveryPoint = false;

 		/* check again */
@ -3319,8 +3305,7 @@ PreallocXlogFiles(XLogRecPtr endptr)
 	bool		use_existent;

 	XLByteToPrevSeg(endptr, _logSegNo);
-	if ((endptr.xrecoff - 1) % XLogSegSize >=
-		(uint32) (0.75 * XLogSegSize))
+	if ((endptr - 1) % XLogSegSize >= (uint32) (0.75 * XLogSegSize))
 	{
 		_logSegNo++;
 		use_existent = true;
@ -3704,7 +3689,7 @@ RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode)
 		{
 			ereport(emode_for_corrupt_record(emode, recptr),
 					(errmsg("incorrect hole size in record at %X/%X",
-							recptr.xlogid, recptr.xrecoff)));
+							(uint32) (recptr >> 32), (uint32) recptr)));
 			return false;
 		}
 		blen = sizeof(BkpBlock) + BLCKSZ - bkpb.hole_length;
@ -3717,7 +3702,7 @@ RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode)
 	{
 		ereport(emode_for_corrupt_record(emode, recptr),
 				(errmsg("incorrect total length in record at %X/%X",
-						recptr.xlogid, recptr.xrecoff)));
+						(uint32) (recptr >> 32), (uint32) recptr)));
 		return false;
 	}

@ -3729,7 +3714,7 @@ RecordIsValid(XLogRecord *record, XLogRecPtr recptr, int emode)
 	{
 		ereport(emode_for_corrupt_record(emode, recptr),
 		(errmsg("incorrect resource manager data checksum in record at %X/%X",
-				recptr.xlogid, recptr.xrecoff)));
+				(uint32) (recptr >> 32), (uint32) recptr)));
 		return false;
 	}

@ -3790,10 +3775,10 @@ ReadRecord(XLogRecPtr *RecPtr, int emode, bool fetching_ckpt)
 		 * In this case, the passed-in record pointer should already be
 		 * pointing to a valid record starting position.
 		 */
-		if (!XRecOffIsValid(RecPtr->xrecoff))
+		if (!XRecOffIsValid(*RecPtr))
 			ereport(PANIC,
 					(errmsg("invalid record offset at %X/%X",
-							RecPtr->xlogid, RecPtr->xrecoff)));
+							(uint32) (*RecPtr >> 32), (uint32) *RecPtr)));

 		/*
 		 * Since we are going to a random position in WAL, forget any prior
@ -3814,7 +3799,7 @@ retry:
 		return NULL;

 	pageHeaderSize = XLogPageHeaderSize((XLogPageHeader) readBuf);
-	targetRecOff = RecPtr->xrecoff % XLOG_BLCKSZ;
+	targetRecOff = (*RecPtr) % XLOG_BLCKSZ;
 	if (targetRecOff == 0)
 	{
 		/*
@ -3824,14 +3809,14 @@ retry:
 		 * XRecOffIsValid rejected the zero-page-offset case otherwise.
 		 */
 		Assert(RecPtr == &tmpRecPtr);
-		RecPtr->xrecoff += pageHeaderSize;
+		(*RecPtr) += pageHeaderSize;
 		targetRecOff = pageHeaderSize;
 	}
 	else if (targetRecOff < pageHeaderSize)
 	{
 		ereport(emode_for_corrupt_record(emode, *RecPtr),
 				(errmsg("invalid record offset at %X/%X",
-						RecPtr->xlogid, RecPtr->xrecoff)));
+						(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 		goto next_record_is_invalid;
 	}
 	if ((((XLogPageHeader) readBuf)->xlp_info & XLP_FIRST_IS_CONTRECORD) &&
@ -3839,7 +3824,7 @@ retry:
 	{
 		ereport(emode_for_corrupt_record(emode, *RecPtr),
 				(errmsg("contrecord is requested by %X/%X",
-						RecPtr->xlogid, RecPtr->xrecoff)));
+						(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 		goto next_record_is_invalid;
 	}

@ -3849,7 +3834,7 @@ retry:
 	 * struct, so it must be on this page, but we cannot safely access any
 	 * other fields yet.
 	 */
-	record = (XLogRecord *) (readBuf + RecPtr->xrecoff % XLOG_BLCKSZ);
+	record = (XLogRecord *) (readBuf + (*RecPtr) % XLOG_BLCKSZ);
 	total_len = record->xl_tot_len;

 	/*
@ -3874,7 +3859,7 @@ retry:
 			/* We treat this as a "bogus data" condition */
 			ereport(emode_for_corrupt_record(emode, *RecPtr),
 					(errmsg("record length %u at %X/%X too long",
-							total_len, RecPtr->xlogid, RecPtr->xrecoff)));
+							total_len, (uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 			goto next_record_is_invalid;
 		}
 		readRecordBufSize = newSize;
@ -3893,7 +3878,7 @@ retry:
 	else
 		gotheader = false;

-	len = XLOG_BLCKSZ - RecPtr->xrecoff % XLOG_BLCKSZ;
+	len = XLOG_BLCKSZ - (*RecPtr) % XLOG_BLCKSZ;
 	if (total_len > len)
 	{
 		/* Need to reassemble record */
@ -3904,11 +3889,10 @@ retry:
 		uint32		gotlen;

 		/* Initialize pagelsn to the beginning of the page this record is on */
-		pagelsn = *RecPtr;
-		pagelsn.xrecoff = (pagelsn.xrecoff / XLOG_BLCKSZ) * XLOG_BLCKSZ;
+		pagelsn = ((*RecPtr) / XLOG_BLCKSZ) * XLOG_BLCKSZ;

 		/* Copy the first fragment of the record from the first page. */
-		memcpy(readRecordBuf, readBuf + RecPtr->xrecoff % XLOG_BLCKSZ, len);
+		memcpy(readRecordBuf, readBuf + (*RecPtr) % XLOG_BLCKSZ, len);
 		buffer = readRecordBuf + len;
 		gotlen = len;

@ -3980,8 +3964,7 @@ retry:
 		/* Record does not cross a page boundary */
 		if (!RecordIsValid(record, *RecPtr, emode))
 			goto next_record_is_invalid;
-		EndRecPtr.xlogid = RecPtr->xlogid;
-		EndRecPtr.xrecoff = RecPtr->xrecoff + MAXALIGN(total_len);
+		EndRecPtr = *RecPtr + MAXALIGN(total_len);

 		ReadRecPtr = *RecPtr;
 		memcpy(readRecordBuf, record, total_len);
@ -3993,8 +3976,8 @@ retry:
 	if (record->xl_rmid == RM_XLOG_ID && record->xl_info == XLOG_SWITCH)
 	{
 		/* Pretend it extends to end of segment */
-		EndRecPtr.xrecoff += XLogSegSize - 1;
-		EndRecPtr.xrecoff -= EndRecPtr.xrecoff % XLogSegSize;
+		EndRecPtr += XLogSegSize - 1;
+		EndRecPtr -= EndRecPtr % XLogSegSize;

 		/*
 		 * Pretend that readBuf contains the last page of the segment. This is
@ -4105,7 +4088,7 @@ ValidXLogPageHeader(XLogPageHeader hdr, int emode)
 	{
 		ereport(emode_for_corrupt_record(emode, recaddr),
 				(errmsg("unexpected pageaddr %X/%X in log segment %s, offset %u",
-						hdr->xlp_pageaddr.xlogid, hdr->xlp_pageaddr.xrecoff,
+						(uint32) (hdr->xlp_pageaddr >> 32), (uint32) hdr->xlp_pageaddr,
 						XLogFileNameP(curFileTLI, readSegNo),
 						readOff)));
 		return false;
@ -4166,7 +4149,7 @@ ValidXLogRecordHeader(XLogRecPtr *RecPtr, XLogRecord *record, int emode,
 		{
 			ereport(emode_for_corrupt_record(emode, *RecPtr),
 					(errmsg("invalid xlog switch record at %X/%X",
-							RecPtr->xlogid, RecPtr->xrecoff)));
+							(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 			return false;
 		}
 	}
@ -4174,7 +4157,7 @@ ValidXLogRecordHeader(XLogRecPtr *RecPtr, XLogRecord *record, int emode,
 	{
 		ereport(emode_for_corrupt_record(emode, *RecPtr),
 				(errmsg("record with zero length at %X/%X",
-						RecPtr->xlogid, RecPtr->xrecoff)));
+						(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 		return false;
 	}
 	if (record->xl_tot_len < SizeOfXLogRecord + record->xl_len ||
@ -4183,14 +4166,14 @@ ValidXLogRecordHeader(XLogRecPtr *RecPtr, XLogRecord *record, int emode,
 	{
 		ereport(emode_for_corrupt_record(emode, *RecPtr),
 				(errmsg("invalid record length at %X/%X",
-						RecPtr->xlogid, RecPtr->xrecoff)));
+						(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 		return false;
 	}
 	if (record->xl_rmid > RM_MAX_ID)
 	{
 		ereport(emode_for_corrupt_record(emode, *RecPtr),
 				(errmsg("invalid resource manager ID %u at %X/%X",
-						record->xl_rmid, RecPtr->xlogid, RecPtr->xrecoff)));
+						record->xl_rmid, (uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 		return false;
 	}
 	if (randAccess)
@ -4203,8 +4186,8 @@ ValidXLogRecordHeader(XLogRecPtr *RecPtr, XLogRecord *record, int emode,
 		{
 			ereport(emode_for_corrupt_record(emode, *RecPtr),
 					(errmsg("record with incorrect prev-link %X/%X at %X/%X",
-							record->xl_prev.xlogid, record->xl_prev.xrecoff,
-							RecPtr->xlogid, RecPtr->xrecoff)));
+							(uint32) (record->xl_prev >> 32), (uint32) record->xl_prev,
+							(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 			return false;
 		}
 	}
@ -4219,8 +4202,8 @@ ValidXLogRecordHeader(XLogRecPtr *RecPtr, XLogRecord *record, int emode,
 		{
 			ereport(emode_for_corrupt_record(emode, *RecPtr),
 					(errmsg("record with incorrect prev-link %X/%X at %X/%X",
-							record->xl_prev.xlogid, record->xl_prev.xrecoff,
-							RecPtr->xlogid, RecPtr->xrecoff)));
+							(uint32) (record->xl_prev >> 32), (uint32) record->xl_prev,
+							(uint32) ((*RecPtr) >> 32), (uint32) *RecPtr)));
 			return false;
 		}
 	}
@ -5193,8 +5176,7 @@ BootStrapXLOG(void)
 	 * segment with logid=0 logseg=1. The very first WAL segment, 0/0, is not
 	 * used, so that we can use 0/0 to mean "before any valid WAL segment".
 	 */
-	checkPoint.redo.xlogid = 0;
-	checkPoint.redo.xrecoff = XLogSegSize + SizeOfXLogLongPHD;
+	checkPoint.redo = XLogSegSize + SizeOfXLogLongPHD;
 	checkPoint.ThisTimeLineID = ThisTimeLineID;
 	checkPoint.fullPageWrites = fullPageWrites;
 	checkPoint.nextXidEpoch = 0;
@ -5217,8 +5199,7 @@ BootStrapXLOG(void)
 	page->xlp_magic = XLOG_PAGE_MAGIC;
 	page->xlp_info = XLP_LONG_HEADER;
 	page->xlp_tli = ThisTimeLineID;
-	page->xlp_pageaddr.xlogid = 0;
-	page->xlp_pageaddr.xrecoff = XLogSegSize;
+	page->xlp_pageaddr = XLogSegSize;
 	longpage = (XLogLongPageHeader) page;
 	longpage->xlp_sysid = sysidentifier;
 	longpage->xlp_seg_size = XLogSegSize;
@ -5226,8 +5207,7 @@ BootStrapXLOG(void)

 	/* Insert the initial checkpoint record */
 	record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
-	record->xl_prev.xlogid = 0;
-	record->xl_prev.xrecoff = 0;
+	record->xl_prev = 0;
 	record->xl_xid = InvalidTransactionId;
 	record->xl_tot_len = SizeOfXLogRecord + sizeof(checkPoint);
 	record->xl_len = sizeof(checkPoint);
@ -6021,7 +6001,7 @@ StartupXLOG(void)

 	if (ControlFile->state < DB_SHUTDOWNED ||
 		ControlFile->state > DB_IN_PRODUCTION ||
-		!XRecOffIsValid(ControlFile->checkPoint.xrecoff))
+		!XRecOffIsValid(ControlFile->checkPoint))
 		ereport(FATAL,
 				(errmsg("control file contains invalid data")));

@ -6157,7 +6137,7 @@ StartupXLOG(void)
 			wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
 			ereport(DEBUG1,
 					(errmsg("checkpoint record is at %X/%X",
-							checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+							(uint32) (checkPointLoc >> 32), (uint32) checkPointLoc)));
 			InRecovery = true;	/* force recovery even if SHUTDOWNED */

 			/*
@ -6197,7 +6177,7 @@ StartupXLOG(void)
 		{
 			ereport(DEBUG1,
 					(errmsg("checkpoint record is at %X/%X",
-							checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+							(uint32) (checkPointLoc >> 32), (uint32) checkPointLoc)));
 		}
 		else if (StandbyMode)
 		{
@ -6216,7 +6196,7 @@ StartupXLOG(void)
 			{
 				ereport(LOG,
 						(errmsg("using previous checkpoint record at %X/%X",
-							  checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+								(uint32) (checkPointLoc >> 32), (uint32) checkPointLoc)));
 				InRecovery = true;		/* force recovery even if SHUTDOWNED */
 			}
 			else
@ -6231,7 +6211,7 @@ StartupXLOG(void)

 	ereport(DEBUG1,
 			(errmsg("redo record is at %X/%X; shutdown %s",
-					checkPoint.redo.xlogid, checkPoint.redo.xrecoff,
+					(uint32) (checkPoint.redo >> 32), (uint32) checkPoint.redo,
 					wasShutdown ? "TRUE" : "FALSE")));
 	ereport(DEBUG1,
 			(errmsg("next transaction ID: %u/%u; next OID: %u",
@ -6542,7 +6522,7 @@ StartupXLOG(void)

 			ereport(LOG,
 					(errmsg("redo starts at %X/%X",
-							ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
+							(uint32) (ReadRecPtr >> 32), (uint32) ReadRecPtr)));

 			/*
 			 * main redo apply loop
@ -6558,8 +6538,8 @@ StartupXLOG(void)

 					initStringInfo(&buf);
 					appendStringInfo(&buf, "REDO @ %X/%X; LSN %X/%X: ",
-									 ReadRecPtr.xlogid, ReadRecPtr.xrecoff,
-									 EndRecPtr.xlogid, EndRecPtr.xrecoff);
+									 (uint32) (ReadRecPtr >> 32), (uint32) ReadRecPtr,
+									 (uint32) (EndRecPtr >> 32), (uint32) EndRecPtr);
 					xlog_outrec(&buf, record);
 					appendStringInfo(&buf, " - ");
 					RmgrTable[record->xl_rmid].rm_desc(&buf,
@ -6687,7 +6667,7 @@ StartupXLOG(void)

 			ereport(LOG,
 					(errmsg("redo done at %X/%X",
-							ReadRecPtr.xlogid, ReadRecPtr.xrecoff)));
+							(uint32) (ReadRecPtr >> 32), (uint32) ReadRecPtr)));
 			xtime = GetLatestXTime();
 			if (xtime)
 				ereport(LOG,
@ -6820,19 +6800,17 @@ StartupXLOG(void)
 	openLogOff = 0;
 	Insert = &XLogCtl->Insert;
 	Insert->PrevRecord = LastRec;
-	XLogCtl->xlblocks[0].xlogid = (openLogSegNo * XLOG_SEG_SIZE) >> 32;
-	XLogCtl->xlblocks[0].xrecoff =
-		((EndOfLog.xrecoff - 1) / XLOG_BLCKSZ + 1) * XLOG_BLCKSZ;
+	XLogCtl->xlblocks[0] = ((EndOfLog - 1) / XLOG_BLCKSZ + 1) * XLOG_BLCKSZ;

 	/*
 	 * Tricky point here: readBuf contains the *last* block that the LastRec
 	 * record spans, not the one it starts in.	The last block is indeed the
 	 * one we want to use.
 	 */
-	Assert(readOff == (XLogCtl->xlblocks[0].xrecoff - XLOG_BLCKSZ) % XLogSegSize);
+	Assert(readOff == (XLogCtl->xlblocks[0] - XLOG_BLCKSZ) % XLogSegSize);
 	memcpy((char *) Insert->currpage, readBuf, XLOG_BLCKSZ);
 	Insert->currpos = (char *) Insert->currpage +
-		(EndOfLog.xrecoff + XLOG_BLCKSZ - XLogCtl->xlblocks[0].xrecoff);
+		(EndOfLog + XLOG_BLCKSZ - XLogCtl->xlblocks[0]);

 	LogwrtResult.Write = LogwrtResult.Flush = EndOfLog;

@ -7053,7 +7031,7 @@ CheckRecoveryConsistency(void)
 		reachedConsistency = true;
 		ereport(LOG,
 				(errmsg("consistent recovery state reached at %X/%X",
-						EndRecPtr.xlogid, EndRecPtr.xrecoff)));
+						(uint32) (EndRecPtr >> 32), (uint32) EndRecPtr)));
 	}

 	/*
@ -7212,7 +7190,7 @@ ReadCheckpointRecord(XLogRecPtr RecPtr, int whichChkpt)
 {
 	XLogRecord *record;

-	if (!XRecOffIsValid(RecPtr.xrecoff))
+	if (!XRecOffIsValid(RecPtr))
 	{
 		switch (whichChkpt)
 		{
@ -7738,13 +7716,9 @@ CreateCheckPoint(int flags)
 		XLogRecPtr	curInsert;

 		INSERT_RECPTR(curInsert, Insert, Insert->curridx);
-		if (curInsert.xlogid == ControlFile->checkPoint.xlogid &&
-			curInsert.xrecoff == ControlFile->checkPoint.xrecoff +
+		if (curInsert == ControlFile->checkPoint + 
 			MAXALIGN(SizeOfXLogRecord + sizeof(CheckPoint)) &&
-			ControlFile->checkPoint.xlogid ==
-			ControlFile->checkPointCopy.redo.xlogid &&
-			ControlFile->checkPoint.xrecoff ==
-			ControlFile->checkPointCopy.redo.xrecoff)
+			ControlFile->checkPoint == ControlFile->checkPointCopy.redo)
 		{
 			LWLockRelease(WALInsertLock);
 			LWLockRelease(CheckpointLock);
@ -8074,8 +8048,8 @@ RecoveryRestartPoint(const CheckPoint *checkPoint)
 				elog(trace_recovery(DEBUG2),
 					 "RM %d not safe to record restart point at %X/%X",
 					 rmid,
-					 checkPoint->redo.xlogid,
-					 checkPoint->redo.xrecoff);
+					 (uint32) (checkPoint->redo >> 32),
+					 (uint32) checkPoint->redo);
 				return;
 			}
 	}
@ -8092,8 +8066,8 @@ RecoveryRestartPoint(const CheckPoint *checkPoint)
 		elog(trace_recovery(DEBUG2),
 			 "could not record restart point at %X/%X because there "
 			 "are unresolved references to invalid pages",
-			 checkPoint->redo.xlogid,
-			 checkPoint->redo.xrecoff);
+			 (uint32) (checkPoint->redo >> 32),
+			 (uint32) checkPoint->redo);
 		return;
 	}

@ -8172,7 +8146,7 @@ CreateRestartPoint(int flags)
 	{
 		ereport(DEBUG2,
 				(errmsg("skipping restartpoint, already performed at %X/%X",
-				  lastCheckPoint.redo.xlogid, lastCheckPoint.redo.xrecoff)));
+						(uint32) (lastCheckPoint.redo >> 32), (uint32) lastCheckPoint.redo)));

 		UpdateMinRecoveryPoint(InvalidXLogRecPtr, true);
 		if (flags & CHECKPOINT_IS_SHUTDOWN)
@ -8282,7 +8256,7 @@ CreateRestartPoint(int flags)
 	xtime = GetLatestXTime();
 	ereport((log_checkpoints ? LOG : DEBUG2),
 			(errmsg("recovery restart point at %X/%X",
-					lastCheckPoint.redo.xlogid, lastCheckPoint.redo.xrecoff),
+					(uint32) (lastCheckPoint.redo >> 32), (uint32) lastCheckPoint.redo),
 		   xtime ? errdetail("last completed transaction was at log time %s",
 							 timestamptz_to_str(xtime)) : 0));

@ -8408,7 +8382,7 @@ XLogRestorePoint(const char *rpName)

 	ereport(LOG,
 			(errmsg("restore point \"%s\" created at %X/%X",
-					rpName, RecPtr.xlogid, RecPtr.xrecoff)));
+					rpName, (uint32) (RecPtr >> 32), (uint32) RecPtr)));

 	return RecPtr;
 }
@ -8757,8 +8731,7 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
 		 * decreasing max_* settings.
 		 */
 		minRecoveryPoint = ControlFile->minRecoveryPoint;
-		if ((minRecoveryPoint.xlogid != 0 || minRecoveryPoint.xrecoff != 0)
-			&& XLByteLT(minRecoveryPoint, lsn))
+		if (minRecoveryPoint != 0 && XLByteLT(minRecoveryPoint, lsn))
 		{
 			ControlFile->minRecoveryPoint = lsn;
 		}
@ -8808,7 +8781,7 @@ xlog_desc(StringInfo buf, uint8 xl_info, char *rec)
 		appendStringInfo(buf, "checkpoint: redo %X/%X; "
 				   "tli %u; fpw %s; xid %u/%u; oid %u; multi %u; offset %u; "
 						 "oldest xid %u in DB %u; oldest running xid %u; %s",
-						 checkpoint->redo.xlogid, checkpoint->redo.xrecoff,
+						 (uint32) (checkpoint->redo >> 32), (uint32) checkpoint->redo,
 						 checkpoint->ThisTimeLineID,
 						 checkpoint->fullPageWrites ? "true" : "false",
 						 checkpoint->nextXidEpoch, checkpoint->nextXid,
@ -8848,7 +8821,7 @@ xlog_desc(StringInfo buf, uint8 xl_info, char *rec)

 		memcpy(&startpoint, rec, sizeof(XLogRecPtr));
 		appendStringInfo(buf, "backup end: %X/%X",
-						 startpoint.xlogid, startpoint.xrecoff);
+						 (uint32) (startpoint >> 32), (uint32) startpoint);
 	}
 	else if (info == XLOG_PARAMETER_CHANGE)
 	{
@ -8894,7 +8867,7 @@ xlog_outrec(StringInfo buf, XLogRecord *record)
 	int			i;

 	appendStringInfo(buf, "prev %X/%X; xid %u",
-					 record->xl_prev.xlogid, record->xl_prev.xrecoff,
+					 (uint32) (record->xl_prev >> 32), (uint32) record->xl_prev,
 					 record->xl_xid);

 	appendStringInfo(buf, "; len %u",
@ -9294,9 +9267,9 @@ do_pg_start_backup(const char *backupidstr, bool fast, char **labelfile)
 					"%Y-%m-%d %H:%M:%S %Z",
 					pg_localtime(&stamp_time, log_timezone));
 		appendStringInfo(&labelfbuf, "START WAL LOCATION: %X/%X (file %s)\n",
-						 startpoint.xlogid, startpoint.xrecoff, xlogfilename);
+						 (uint32) (startpoint >> 32), (uint32) startpoint, xlogfilename);
 		appendStringInfo(&labelfbuf, "CHECKPOINT LOCATION: %X/%X\n",
-						 checkpointloc.xlogid, checkpointloc.xrecoff);
+						 (uint32) (checkpointloc >> 32), (uint32) checkpointloc);
 		appendStringInfo(&labelfbuf, "BACKUP METHOD: %s\n",
 						 exclusive ? "pg_start_backup" : "streamed");
 		appendStringInfo(&labelfbuf, "BACKUP FROM: %s\n",
@ -9416,6 +9389,8 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)
 	bool		reported_waiting = false;
 	char	   *remaining;
 	char	   *ptr;
+	uint32		hi,
+				lo;

 	backup_started_in_recovery = RecoveryInProgress();

@ -9520,11 +9495,12 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)
 	 * but we are not expecting any variability in the file format).
 	 */
 	if (sscanf(labelfile, "START WAL LOCATION: %X/%X (file %24s)%c",
-			   &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename,
+			   &hi, &lo, startxlogfilename,
 			   &ch) != 4 || ch != '\n')
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE)));
+	startpoint = ((uint64) hi) << 32 | lo;
 	remaining = strchr(labelfile, '\n') + 1;	/* %n is not portable enough */

 	/*
@ -9632,7 +9608,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)
 	 */
 	XLByteToSeg(startpoint, _logSegNo);
 	BackupHistoryFilePath(histfilepath, ThisTimeLineID, _logSegNo,
-						  startpoint.xrecoff % XLogSegSize);
+						  (uint32) (startpoint % XLogSegSize));
 	fp = AllocateFile(histfilepath, "w");
 	if (!fp)
 		ereport(ERROR,
@ -9640,9 +9616,9 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)
 				 errmsg("could not create file \"%s\": %m",
 						histfilepath)));
 	fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
-			startpoint.xlogid, startpoint.xrecoff, startxlogfilename);
+			(uint32) (startpoint >> 32), (uint32) startpoint, startxlogfilename);
 	fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n",
-			stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename);
+			(uint32) (stoppoint >> 32), (uint32) stoppoint, stopxlogfilename);
 	/* transfer remaining lines from label to history file */
 	fprintf(fp, "%s", remaining);
 	fprintf(fp, "STOP TIME: %s\n", strfbuf);
@ -9685,7 +9661,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)

 		XLByteToSeg(startpoint, _logSegNo);
 		BackupHistoryFileName(histfilename, ThisTimeLineID, _logSegNo,
-							  startpoint.xrecoff % XLogSegSize);
+							  (uint32) (startpoint % XLogSegSize));

 		seconds_before_warning = 60;
 		waits = 0;
@ -9861,6 +9837,8 @@ read_backup_label(XLogRecPtr *checkPointLoc, bool *backupEndRequired,
 	char		ch;
 	char		backuptype[20];
 	char		backupfrom[20];
+	uint32		hi,
+				lo;

 	*backupEndRequired = false;
 	*backupFromStandby = false;
@ -9885,17 +9863,17 @@ read_backup_label(XLogRecPtr *checkPointLoc, bool *backupEndRequired,
 	 * format).
 	 */
 	if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c",
-			   &RedoStartLSN.xlogid, &RedoStartLSN.xrecoff, &tli,
-			   startxlogfilename, &ch) != 5 || ch != '\n')
+			   &hi, &lo, &tli, startxlogfilename, &ch) != 5 || ch != '\n')
 		ereport(FATAL,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE)));
+	RedoStartLSN = ((uint64) hi) << 32 | lo;
 	if (fscanf(lfp, "CHECKPOINT LOCATION: %X/%X%c",
-			   &checkPointLoc->xlogid, &checkPointLoc->xrecoff,
-			   &ch) != 3 || ch != '\n')
+			   &hi, &lo, &ch) != 3 || ch != '\n')
 		ereport(FATAL,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE)));
+	*checkPointLoc = ((uint64) hi) << 32 | lo;

 	/*
 	 * BACKUP METHOD and BACKUP FROM lines are new in 9.2. We can't restore
@ -10018,7 +9996,7 @@ static bool
 XLogPageRead(XLogRecPtr *RecPtr, int emode, bool fetching_ckpt,
 			 bool randAccess)
 {
-	static XLogRecPtr receivedUpto = {0, 0};
+	static XLogRecPtr receivedUpto = 0;
 	bool		switched_segment = false;
 	uint32		targetPageOff;
 	uint32		targetRecOff;
@ -10026,8 +10004,8 @@ XLogPageRead(XLogRecPtr *RecPtr, int emode, bool fetching_ckpt,
 	static pg_time_t last_fail_time = 0;

 	XLByteToSeg(*RecPtr, targetSegNo);
-	targetPageOff = ((RecPtr->xrecoff % XLogSegSize) / XLOG_BLCKSZ) * XLOG_BLCKSZ;
-	targetRecOff = RecPtr->xrecoff % XLOG_BLCKSZ;
+	targetPageOff = (((*RecPtr) % XLogSegSize) / XLOG_BLCKSZ) * XLOG_BLCKSZ;
+	targetRecOff = (*RecPtr) % XLOG_BLCKSZ;

 	/* Fast exit if we have read the record in the current buffer already */
 	if (failedSources == 0 && targetSegNo == readSegNo &&
@ -10308,13 +10286,12 @@ retry:
 	 */
 	if (readSource == XLOG_FROM_STREAM)
 	{
-		if (RecPtr->xlogid != receivedUpto.xlogid ||
-			(RecPtr->xrecoff / XLOG_BLCKSZ) != (receivedUpto.xrecoff / XLOG_BLCKSZ))
+		if (((*RecPtr) / XLOG_BLCKSZ) != (receivedUpto / XLOG_BLCKSZ))
 		{
 			readLen = XLOG_BLCKSZ;
 		}
 		else
-			readLen = receivedUpto.xrecoff % XLogSegSize - targetPageOff;
+			readLen = receivedUpto % XLogSegSize - targetPageOff;
 	}
 	else
 		readLen = XLOG_BLCKSZ;
@ -10420,7 +10397,7 @@ triggered:
 static int
 emode_for_corrupt_record(int emode, XLogRecPtr RecPtr)
 {
-	static XLogRecPtr lastComplaint = {0, 0};
+	static XLogRecPtr lastComplaint = 0;

 	if (readSource == XLOG_FROM_PG_XLOG && emode == LOG)
 	{
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@ -57,7 +57,7 @@ pg_start_backup(PG_FUNCTION_ARGS)
 	startpoint = do_pg_start_backup(backupidstr, fast, NULL);

 	snprintf(startxlogstr, sizeof(startxlogstr), "%X/%X",
-			 startpoint.xlogid, startpoint.xrecoff);
+			 (uint32) (startpoint >> 32), (uint32) startpoint);
 	PG_RETURN_TEXT_P(cstring_to_text(startxlogstr));
 }

@ -83,7 +83,7 @@ pg_stop_backup(PG_FUNCTION_ARGS)
 	stoppoint = do_pg_stop_backup(NULL, true);

 	snprintf(stopxlogstr, sizeof(stopxlogstr), "%X/%X",
-			 stoppoint.xlogid, stoppoint.xrecoff);
+			 (uint32) (stoppoint >> 32), (uint32) stoppoint);
 	PG_RETURN_TEXT_P(cstring_to_text(stopxlogstr));
 }

@ -113,7 +113,7 @@ pg_switch_xlog(PG_FUNCTION_ARGS)
 	 * As a convenience, return the WAL location of the switch record
 	 */
 	snprintf(location, sizeof(location), "%X/%X",
-			 switchpoint.xlogid, switchpoint.xrecoff);
+			 (uint32) (switchpoint >> 32), (uint32) switchpoint);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -158,7 +158,7 @@ pg_create_restore_point(PG_FUNCTION_ARGS)
 	 * As a convenience, return the WAL location of the restore point record
 	 */
 	snprintf(location, sizeof(location), "%X/%X",
-			 restorepoint.xlogid, restorepoint.xrecoff);
+			 (uint32) (restorepoint >> 32), (uint32) restorepoint);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -184,7 +184,7 @@ pg_current_xlog_location(PG_FUNCTION_ARGS)
 	current_recptr = GetXLogWriteRecPtr();

 	snprintf(location, sizeof(location), "%X/%X",
-			 current_recptr.xlogid, current_recptr.xrecoff);
+			 (uint32) (current_recptr >> 32), (uint32) current_recptr);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -208,7 +208,7 @@ pg_current_xlog_insert_location(PG_FUNCTION_ARGS)
 	current_recptr = GetXLogInsertRecPtr();

 	snprintf(location, sizeof(location), "%X/%X",
-			 current_recptr.xlogid, current_recptr.xrecoff);
+			 (uint32) (current_recptr >> 32), (uint32) current_recptr);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -226,11 +226,11 @@ pg_last_xlog_receive_location(PG_FUNCTION_ARGS)

 	recptr = GetWalRcvWriteRecPtr(NULL);

-	if (recptr.xlogid == 0 && recptr.xrecoff == 0)
+	if (recptr == 0)
 		PG_RETURN_NULL();

 	snprintf(location, sizeof(location), "%X/%X",
-			 recptr.xlogid, recptr.xrecoff);
+			 (uint32) (recptr >> 32), (uint32) recptr);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -248,11 +248,11 @@ pg_last_xlog_replay_location(PG_FUNCTION_ARGS)

 	recptr = GetXLogReplayRecPtr(NULL);

-	if (recptr.xlogid == 0 && recptr.xrecoff == 0)
+	if (recptr == 0)
 		PG_RETURN_NULL();

 	snprintf(location, sizeof(location), "%X/%X",
-			 recptr.xlogid, recptr.xrecoff);
+			 (uint32) (recptr >> 32), (uint32) recptr);
 	PG_RETURN_TEXT_P(cstring_to_text(location));
 }

@ -269,8 +269,8 @@ pg_xlogfile_name_offset(PG_FUNCTION_ARGS)
 {
 	text	   *location = PG_GETARG_TEXT_P(0);
 	char	   *locationstr;
-	unsigned int uxlogid;
-	unsigned int uxrecoff;
+	uint32		hi,
+				lo;
 	XLogSegNo	xlogsegno;
 	uint32		xrecoff;
 	XLogRecPtr	locationpoint;
@ -294,14 +294,12 @@ pg_xlogfile_name_offset(PG_FUNCTION_ARGS)

 	validate_xlog_location(locationstr);

-	if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2)
+	if (sscanf(locationstr, "%X/%X", &hi, &lo) != 2)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("could not parse transaction log location \"%s\"",
 						locationstr)));
-
-	locationpoint.xlogid = uxlogid;
-	locationpoint.xrecoff = uxrecoff;
+	locationpoint = ((uint64) hi) << 32 | lo;

 	/*
 	 * Construct a tuple descriptor for the result row.  This must match this
@ -327,7 +325,7 @@ pg_xlogfile_name_offset(PG_FUNCTION_ARGS)
 	/*
 	 * offset
 	 */
-	xrecoff = locationpoint.xrecoff % XLogSegSize;
+	xrecoff = locationpoint % XLogSegSize;

 	values[1] = UInt32GetDatum(xrecoff);
 	isnull[1] = false;
@ -351,8 +349,8 @@ pg_xlogfile_name(PG_FUNCTION_ARGS)
 {
 	text	   *location = PG_GETARG_TEXT_P(0);
 	char	   *locationstr;
-	unsigned int uxlogid;
-	unsigned int uxrecoff;
+	uint32		hi,
+				lo;
 	XLogSegNo	xlogsegno;
 	XLogRecPtr	locationpoint;
 	char		xlogfilename[MAXFNAMELEN];
@ -367,14 +365,12 @@ pg_xlogfile_name(PG_FUNCTION_ARGS)

 	validate_xlog_location(locationstr);

-	if (sscanf(locationstr, "%X/%X", &uxlogid, &uxrecoff) != 2)
+	if (sscanf(locationstr, "%X/%X", &hi, &lo) != 2)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("could not parse transaction log location \"%s\"",
 						locationstr)));
-
-	locationpoint.xlogid = uxlogid;
-	locationpoint.xrecoff = uxrecoff;
+	locationpoint = ((uint64) hi) << 32 | lo;

 	XLByteToPrevSeg(locationpoint, xlogsegno);
 	XLogFileName(xlogfilename, ThisTimeLineID, xlogsegno);
@ -514,6 +510,8 @@ pg_xlog_location_diff(PG_FUNCTION_ARGS)
 	Numeric		result;
 	uint64		bytes1,
 				bytes2;
+	uint32		hi,
+				lo;

 	/*
 	 * Read and parse input
@ -524,17 +522,20 @@ pg_xlog_location_diff(PG_FUNCTION_ARGS)
 	validate_xlog_location(str1);
 	validate_xlog_location(str2);

-	if (sscanf(str1, "%X/%X", &loc1.xlogid, &loc1.xrecoff) != 2)
+	if (sscanf(str1, "%X/%X", &hi, &lo) != 2)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 		   errmsg("could not parse transaction log location \"%s\"", str1)));
-	if (sscanf(str2, "%X/%X", &loc2.xlogid, &loc2.xrecoff) != 2)
+	loc1 = ((uint64) hi) << 32 | lo;
+
+	if (sscanf(str2, "%X/%X", &hi, &lo) != 2)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 		   errmsg("could not parse transaction log location \"%s\"", str2)));
+	loc2 = ((uint64) hi) << 32 | lo;

-	bytes1 = (((uint64)loc1.xlogid) << 32L) + loc1.xrecoff;
-	bytes2 = (((uint64)loc2.xlogid) << 32L) + loc2.xrecoff;
+	bytes1 = (uint64) loc1;
+	bytes2 = (uint64) loc2;

 	/*
 	 * result = bytes1 - bytes2.
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@ -631,7 +631,7 @@ CheckArchiveTimeout(void)
 		 * If the returned pointer points exactly to a segment boundary,
 		 * assume nothing happened.
 		 */
-		if ((switchpoint.xrecoff % XLogSegSize) != 0)
+		if ((switchpoint % XLogSegSize) != 0)
 			ereport(DEBUG1,
 				(errmsg("transaction log switch forced (archive_timeout=%d)",
 						XLogArchiveTimeout)));
@ -778,10 +778,7 @@ IsCheckpointOnSchedule(double progress)
 	if (!RecoveryInProgress())
 	{
 		recptr = GetInsertRecPtr();
-		elapsed_xlogs =
-			(((double) ((uint64) (recptr.xlogid - ckpt_start_recptr.xlogid) << 32L)) +
-			 ((double) recptr.xrecoff - (double) ckpt_start_recptr.xrecoff) / XLogSegSize) /
-			CheckPointSegments;
+		elapsed_xlogs = (((double) (recptr - ckpt_start_recptr)) / XLogSegSize) / CheckPointSegments;

 		if (progress < elapsed_xlogs)
 		{
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@ -497,7 +497,7 @@ SendXlogRecPtrResult(XLogRecPtr ptr)
 	StringInfoData buf;
 	char		str[MAXFNAMELEN];

-	snprintf(str, sizeof(str), "%X/%X", ptr.xlogid, ptr.xrecoff);
+	snprintf(str, sizeof(str), "%X/%X", (uint32) (ptr >> 32), (uint32) ptr);

 	pq_beginmessage(&buf, 'T'); /* RowDescription */
 	pq_sendint(&buf, 1, 2);		/* 1 field */
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@ -156,7 +156,7 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)

 	/* Start streaming from the point requested by startup process */
 	snprintf(cmd, sizeof(cmd), "START_REPLICATION %X/%X",
-			 startpoint.xlogid, startpoint.xrecoff);
+			 (uint32) (startpoint >> 32), (uint32) startpoint);
 	res = libpqrcv_PQexec(cmd);
 	if (PQresultStatus(res) != PGRES_COPY_BOTH)
 	{
--- a/src/backend/replication/repl_scanner.l
+++ b/src/backend/replication/repl_scanner.l
@ -72,8 +72,11 @@ START_REPLICATION	{ return K_START_REPLICATION; }
 " "				;

 {hexdigit}+\/{hexdigit}+		{
-					if (sscanf(yytext, "%X/%X", &yylval.recptr.xlogid, &yylval.recptr.xrecoff) != 2)
+					uint32	hi,
+							lo;
+					if (sscanf(yytext, "%X/%X", &hi, &lo) != 2)
 						yyerror("invalid streaming start location");
+					yylval.recptr = ((uint64) hi) << 32 | lo;
 					return RECPTR;
 				}

--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@ -145,7 +145,7 @@ SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
 		new_status = (char *) palloc(len + 32 + 1);
 		memcpy(new_status, old_status, len);
 		sprintf(new_status + len, " waiting for %X/%X",
-				XactCommitLSN.xlogid, XactCommitLSN.xrecoff);
+				(uint32) (XactCommitLSN >> 32), (uint32) XactCommitLSN);
 		set_ps_display(new_status, false);
 		new_status[len] = '\0'; /* truncate off " waiting ..." */
 	}
@ -255,8 +255,7 @@ SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
 	 */
 	Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
 	MyProc->syncRepState = SYNC_REP_NOT_WAITING;
-	MyProc->waitLSN.xlogid = 0;
-	MyProc->waitLSN.xrecoff = 0;
+	MyProc->waitLSN = 0;

 	if (new_status)
 	{
@ -440,12 +439,8 @@ SyncRepReleaseWaiters(void)
 	LWLockRelease(SyncRepLock);

 	elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X",
-		 numwrite,
-		 MyWalSnd->write.xlogid,
-		 MyWalSnd->write.xrecoff,
-		 numflush,
-		 MyWalSnd->flush.xlogid,
-		 MyWalSnd->flush.xrecoff);
+		 numwrite, (uint32) (MyWalSnd->write >> 32), (uint32) MyWalSnd->write,
+		 numflush, (uint32) (MyWalSnd->flush >> 32), (uint32) MyWalSnd->flush);

 	/*
 	 * If we are managing the highest priority standby, though we weren't
@ -630,8 +625,7 @@ SyncRepQueueIsOrderedByLSN(int mode)

 	Assert(mode >= 0 && mode < NUM_SYNC_REP_WAIT_MODE);

-	lastLSN.xlogid = 0;
-	lastLSN.xrecoff = 0;
+	lastLSN = 0;

 	proc = (PGPROC *) SHMQueueNext(&(WalSndCtl->SyncRepQueue[mode]),
 								   &(WalSndCtl->SyncRepQueue[mode]),
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@ -516,7 +516,7 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr)
 		}

 		/* Calculate the start offset of the received logs */
-		startoff = recptr.xrecoff % XLogSegSize;
+		startoff = recptr % XLogSegSize;

 		if (startoff + nbytes > XLogSegSize)
 			segbytes = XLogSegSize - startoff;
@ -601,8 +601,8 @@ XLogWalRcvFlush(bool dying)
 			char		activitymsg[50];

 			snprintf(activitymsg, sizeof(activitymsg), "streaming %X/%X",
-					 LogstreamResult.Write.xlogid,
-					 LogstreamResult.Write.xrecoff);
+					 (uint32) (LogstreamResult.Write >> 32),
+					 (uint32) LogstreamResult.Write);
 			set_ps_display(activitymsg, false);
 		}

@ -657,9 +657,9 @@ XLogWalRcvSendReply(void)
 	reply_message.sendTime = now;

 	elog(DEBUG2, "sending write %X/%X flush %X/%X apply %X/%X",
-		 reply_message.write.xlogid, reply_message.write.xrecoff,
-		 reply_message.flush.xlogid, reply_message.flush.xrecoff,
-		 reply_message.apply.xlogid, reply_message.apply.xrecoff);
+		 (uint32) (reply_message.write >> 32), (uint32) reply_message.write,
+		 (uint32) (reply_message.flush >> 32), (uint32) reply_message.flush,
+		 (uint32) (reply_message.apply >> 32), (uint32) reply_message.apply);

 	/* Prepend with the message type and send it. */
 	buf[0] = 'r';
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@ -185,8 +185,8 @@ RequestXLogStreaming(XLogRecPtr recptr, const char *conninfo)
 	 * being created by XLOG streaming, which might cause trouble later on if
 	 * the segment is e.g archived.
 	 */
-	if (recptr.xrecoff % XLogSegSize != 0)
-		recptr.xrecoff -= recptr.xrecoff % XLogSegSize;
+	if (recptr % XLogSegSize != 0)
+		recptr -= recptr % XLogSegSize;

 	SpinLockAcquire(&walrcv->mutex);

@ -204,8 +204,7 @@ RequestXLogStreaming(XLogRecPtr recptr, const char *conninfo)
 	 * If this is the first startup of walreceiver, we initialize receivedUpto
 	 * and latestChunkStart to receiveStart.
 	 */
-	if (walrcv->receiveStart.xlogid == 0 &&
-		walrcv->receiveStart.xrecoff == 0)
+	if (walrcv->receiveStart == 0)
 	{
 		walrcv->receivedUpto = recptr;
 		walrcv->latestChunkStart = recptr;
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@ -94,7 +94,7 @@ static uint32 sendOff = 0;
 * How far have we sent WAL already? This is also advertised in
 * MyWalSnd->sentPtr.  (Actually, this is the next WAL location to send.)
 */
-static XLogRecPtr sentPtr = {0, 0};
+static XLogRecPtr sentPtr = 0;

 /*
 * Buffer for processing reply messages.
@ -300,8 +300,7 @@ IdentifySystem(void)

 	logptr = am_cascading_walsender ? GetStandbyFlushRecPtr() : GetInsertRecPtr();

-	snprintf(xpos, sizeof(xpos), "%X/%X",
-			 logptr.xlogid, logptr.xrecoff);
+	snprintf(xpos, sizeof(xpos), "%X/%X", (uint32) (logptr >> 32), (uint32) logptr);

 	/* Send a RowDescription message */
 	pq_beginmessage(&buf, 'T');
@ -613,9 +612,9 @@ ProcessStandbyReplyMessage(void)
 	pq_copymsgbytes(&reply_message, (char *) &reply, sizeof(StandbyReplyMessage));

 	elog(DEBUG2, "write %X/%X flush %X/%X apply %X/%X",
-		 reply.write.xlogid, reply.write.xrecoff,
-		 reply.flush.xlogid, reply.flush.xrecoff,
-		 reply.apply.xlogid, reply.apply.xrecoff);
+		 (uint32) (reply.write << 32), (uint32) reply.write,
+		 (uint32) (reply.flush << 32), (uint32) reply.flush,
+		 (uint32) (reply.apply << 32), (uint32) reply.apply);

 	/*
 	 * Update shared state for this WalSender process based on reply data from
@ -990,7 +989,7 @@ retry:
 		int			segbytes;
 		int			readbytes;

-		startoff = recptr.xrecoff % XLogSegSize;
+		startoff = recptr % XLogSegSize;

 		if (sendFile < 0 || !XLByteInSeg(recptr, sendSegNo))
 		{
@ -1156,12 +1155,6 @@ XLogSend(char *msgbuf, bool *caughtup)
 	startptr = sentPtr;
 	endptr = startptr;
 	XLByteAdvance(endptr, MAX_SEND_SIZE);
-	if (endptr.xlogid != startptr.xlogid)
-	{
-		/* Don't cross a logfile boundary within one message */
-		Assert(endptr.xlogid == startptr.xlogid + 1);
-		endptr.xrecoff = 0;
-	}

 	/* if we went beyond SendRqstPtr, back off */
 	if (XLByteLE(SendRqstPtr, endptr))
@ -1172,14 +1165,11 @@ XLogSend(char *msgbuf, bool *caughtup)
 	else
 	{
 		/* round down to page boundary. */
-		endptr.xrecoff -= (endptr.xrecoff % XLOG_BLCKSZ);
+		endptr -= (endptr % XLOG_BLCKSZ);
 		*caughtup = false;
 	}

-	if (endptr.xrecoff == 0)
-		nbytes = 0x100000000L - (uint64) startptr.xrecoff;
-	else
-		nbytes = endptr.xrecoff - startptr.xrecoff;
+	nbytes = endptr - startptr;
 	Assert(nbytes <= MAX_SEND_SIZE);

 	/*
@ -1223,7 +1213,7 @@ XLogSend(char *msgbuf, bool *caughtup)
 		char		activitymsg[50];

 		snprintf(activitymsg, sizeof(activitymsg), "streaming %X/%X",
-				 sentPtr.xlogid, sentPtr.xrecoff);
+				 (uint32) (sentPtr >> 32), (uint32) sentPtr);
 		set_ps_display(activitymsg, false);
 	}

@ -1565,25 +1555,25 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
 			values[1] = CStringGetTextDatum(WalSndGetStateString(state));

 			snprintf(location, sizeof(location), "%X/%X",
-					 sentPtr.xlogid, sentPtr.xrecoff);
+					 (uint32) (sentPtr >> 32), (uint32) sentPtr);
 			values[2] = CStringGetTextDatum(location);

-			if (write.xlogid == 0 && write.xrecoff == 0)
+			if (write == 0)
 				nulls[3] = true;
 			snprintf(location, sizeof(location), "%X/%X",
-					 write.xlogid, write.xrecoff);
+					 (uint32) (write >> 32), (uint32) write);
 			values[3] = CStringGetTextDatum(location);

-			if (flush.xlogid == 0 && flush.xrecoff == 0)
+			if (flush == 0)
 				nulls[4] = true;
 			snprintf(location, sizeof(location), "%X/%X",
-					 flush.xlogid, flush.xrecoff);
+					 (uint32) (flush >> 32), (uint32) flush);
 			values[4] = CStringGetTextDatum(location);

-			if (apply.xlogid == 0 && apply.xrecoff == 0)
+			if (apply == 0)
 				nulls[5] = true;
 			snprintf(location, sizeof(location), "%X/%X",
-					 apply.xlogid, apply.xrecoff);
+					 (uint32) (apply >> 32), (uint32) apply);
 			values[5] = CStringGetTextDatum(location);

 			values[6] = Int32GetDatum(sync_priority[i]);
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@ -936,7 +936,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
 		elog(trace_recovery(DEBUG2),
 			 "snapshot of %u running transactions overflowed (lsn %X/%X oldest xid %u latest complete %u next xid %u)",
 			 CurrRunningXacts->xcnt,
-			 recptr.xlogid, recptr.xrecoff,
+			 (uint32) (recptr >> 32), (uint32) recptr,
 			 CurrRunningXacts->oldestRunningXid,
 			 CurrRunningXacts->latestCompletedXid,
 			 CurrRunningXacts->nextXid);
@ -944,7 +944,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)
 		elog(trace_recovery(DEBUG2),
 			 "snapshot of %u running transaction ids (lsn %X/%X oldest xid %u latest complete %u next xid %u)",
 			 CurrRunningXacts->xcnt,
-			 recptr.xlogid, recptr.xrecoff,
+			 (uint32) (recptr >> 32), (uint32) recptr,
 			 CurrRunningXacts->oldestRunningXid,
 			 CurrRunningXacts->latestCompletedXid,
 			 CurrRunningXacts->nextXid);
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@ -376,8 +376,7 @@ InitProcess(void)
 	MyProc->recoveryConflictPending = false;

 	/* Initialize fields for sync rep */
-	MyProc->waitLSN.xlogid = 0;
-	MyProc->waitLSN.xrecoff = 0;
+	MyProc->waitLSN = 0;
 	MyProc->syncRepState = SYNC_REP_NOT_WAITING;
 	SHMQueueElemInit(&(MyProc->syncRepLinks));

--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@ -162,6 +162,8 @@ reached_end_position(XLogRecPtr segendpos, uint32 timeline, bool segment_finishe
 		if (r == 1)
 		{
 			char		xlogend[64];
+			uint32		hi,
+						lo;

 			MemSet(xlogend, 0, sizeof(xlogend));
 			r = read(bgpipe[0], xlogend, sizeof(xlogend));
@ -172,12 +174,13 @@ reached_end_position(XLogRecPtr segendpos, uint32 timeline, bool segment_finishe
 				exit(1);
 			}

-			if (sscanf(xlogend, "%X/%X", &xlogendptr.xlogid, &xlogendptr.xrecoff) != 2)
+			if (sscanf(xlogend, "%X/%X", &hi, &lo) != 2)
 			{
 				fprintf(stderr, _("%s: could not parse xlog end position \"%s\"\n"),
 						progname, xlogend);
 				exit(1);
 			}
+			xlogendptr = ((uint64) hi) << 32 | lo;
 			has_xlogendptr = 1;

 			/*
@ -207,9 +210,7 @@ reached_end_position(XLogRecPtr segendpos, uint32 timeline, bool segment_finishe
 	 * At this point we have an end pointer, so compare it to the current
 	 * position to figure out if it's time to stop.
 	 */
-	if (segendpos.xlogid > xlogendptr.xlogid ||
-		(segendpos.xlogid == xlogendptr.xlogid &&
-		 segendpos.xrecoff >= xlogendptr.xrecoff))
+	if (segendpos >= xlogendptr)
 		return true;

 	/*
@ -255,20 +256,23 @@ static void
 StartLogStreamer(char *startpos, uint32 timeline, char *sysidentifier)
 {
 	logstreamer_param *param;
+	uint32		hi,
+				lo;

 	param = xmalloc0(sizeof(logstreamer_param));
 	param->timeline = timeline;
 	param->sysidentifier = sysidentifier;

 	/* Convert the starting position */
-	if (sscanf(startpos, "%X/%X", &param->startptr.xlogid, &param->startptr.xrecoff) != 2)
+	if (sscanf(startpos, "%X/%X", &hi, &lo) != 2)
 	{
 		fprintf(stderr, _("%s: invalid format of xlog location: %s\n"),
 				progname, startpos);
 		disconnect_and_exit(1);
 	}
+	param->startptr = ((uint64) hi) << 32 | lo;
 	/* Round off to even segment position */
-	param->startptr.xrecoff -= param->startptr.xrecoff % XLOG_SEG_SIZE;
+	param->startptr -= param->startptr % XLOG_SEG_SIZE;

 #ifndef WIN32
 	/* Create our background pipe */
--- a/src/bin/pg_basebackup/pg_receivexlog.c
+++ b/src/bin/pg_basebackup/pg_receivexlog.c
@ -77,7 +77,9 @@ stop_streaming(XLogRecPtr segendpos, uint32 timeline, bool segment_finished)
 {
 	if (verbose && segment_finished)
 		fprintf(stderr, _("%s: finished segment at %X/%X (timeline %u)\n"),
-				progname, segendpos.xlogid, segendpos.xrecoff, timeline);
+				progname,
+				(uint32) (segendpos >> 32), (uint32) segendpos,
+				timeline);

 	if (time_to_abort)
 	{
@ -212,6 +214,8 @@ StreamLog(void)
 	PGresult   *res;
 	uint32		timeline;
 	XLogRecPtr	startpos;
+	uint32		hi,
+				lo;

 	/*
 	 * Connect in replication mode to the server
@ -239,12 +243,13 @@ StreamLog(void)
 		disconnect_and_exit(1);
 	}
 	timeline = atoi(PQgetvalue(res, 0, 1));
-	if (sscanf(PQgetvalue(res, 0, 2), "%X/%X", &startpos.xlogid, &startpos.xrecoff) != 2)
+	if (sscanf(PQgetvalue(res, 0, 2), "%X/%X", &hi, &lo) != 2)
 	{
 		fprintf(stderr, _("%s: could not parse log start position from value \"%s\"\n"),
 				progname, PQgetvalue(res, 0, 2));
 		disconnect_and_exit(1);
 	}
+	startpos = ((uint64) hi) << 32 | lo;
 	PQclear(res);

 	/*
@ -255,14 +260,16 @@ StreamLog(void)
 	/*
 	 * Always start streaming at the beginning of a segment
 	 */
-	startpos.xrecoff -= startpos.xrecoff % XLOG_SEG_SIZE;
+	startpos -= startpos % XLOG_SEG_SIZE;

 	/*
 	 * Start the replication
 	 */
 	if (verbose)
 		fprintf(stderr, _("%s: starting log streaming at %X/%X (timeline %u)\n"),
-				progname, startpos.xlogid, startpos.xrecoff, timeline);
+				progname,
+				(uint32) (startpos >> 32), (uint32) startpos,
+				timeline);

 	ReceiveXlogStream(conn, startpos, timeline, NULL, basedir,
 					  stop_streaming,
--- a/src/bin/pg_basebackup/receivelog.c
+++ b/src/bin/pg_basebackup/receivelog.c
@ -38,8 +38,6 @@
 #define STREAMING_HEADER_SIZE (1+sizeof(WalDataMessageHeader))
 #define STREAMING_KEEPALIVE_SIZE (1+sizeof(PrimaryKeepaliveMessage))

-const XLogRecPtr InvalidXLogRecPtr = {0, 0};
-
 /*
 * Open a new WAL file in the specified directory. Store the name
 * (not including the full directory) in namebuf. Assumes there is
@ -310,7 +308,8 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline, char *sysi
 	}

 	/* Initiate the replication stream at specified location */
-	snprintf(query, sizeof(query), "START_REPLICATION %X/%X", startpos.xlogid, startpos.xrecoff);
+	snprintf(query, sizeof(query), "START_REPLICATION %X/%X",
+			 (uint32) (startpos >> 32), (uint32) startpos);
 	res = PQexec(conn, query);
 	if (PQresultStatus(res) != PGRES_COPY_BOTH)
 	{
@ -471,7 +470,7 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline, char *sysi

 		/* Extract WAL location for this block */
 		memcpy(&blockpos, copybuf + 1, 8);
-		xlogoff = blockpos.xrecoff % XLOG_SEG_SIZE;
+		xlogoff = blockpos % XLOG_SEG_SIZE;

 		/*
 		 * Verify that the initial location in the stream matches where we
@ -543,7 +542,7 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline, char *sysi
 			xlogoff += bytes_to_write;

 			/* Did we reach the end of a WAL segment? */
-			if (blockpos.xrecoff % XLOG_SEG_SIZE == 0)
+			if (blockpos % XLOG_SEG_SIZE == 0)
 			{
 				if (!close_walfile(walfile, basedir, current_walfile_name, false))
 					/* Error message written in close_walfile() */
--- a/src/bin/pg_controldata/pg_controldata.c
+++ b/src/bin/pg_controldata/pg_controldata.c
@ -193,14 +193,14 @@ main(int argc, char *argv[])
 	printf(_("pg_control last modified:             %s\n"),
 		   pgctime_str);
 	printf(_("Latest checkpoint location:           %X/%X\n"),
-		   ControlFile.checkPoint.xlogid,
-		   ControlFile.checkPoint.xrecoff);
+		   (uint32) (ControlFile.checkPoint >> 32),
+		   (uint32) ControlFile.checkPoint);
 	printf(_("Prior checkpoint location:            %X/%X\n"),
-		   ControlFile.prevCheckPoint.xlogid,
-		   ControlFile.prevCheckPoint.xrecoff);
+		   (uint32) (ControlFile.prevCheckPoint >> 32),
+		   (uint32) ControlFile.prevCheckPoint);
 	printf(_("Latest checkpoint's REDO location:    %X/%X\n"),
-		   ControlFile.checkPointCopy.redo.xlogid,
-		   ControlFile.checkPointCopy.redo.xrecoff);
+		   (uint32) (ControlFile.checkPointCopy.redo >> 32),
+		   (uint32) ControlFile.checkPointCopy.redo);
 	printf(_("Latest checkpoint's TimeLineID:       %u\n"),
 		   ControlFile.checkPointCopy.ThisTimeLineID);
 	printf(_("Latest checkpoint's full_page_writes: %s\n"),
@ -223,14 +223,14 @@ main(int argc, char *argv[])
 	printf(_("Time of latest checkpoint:            %s\n"),
 		   ckpttime_str);
 	printf(_("Minimum recovery ending location:     %X/%X\n"),
-		   ControlFile.minRecoveryPoint.xlogid,
-		   ControlFile.minRecoveryPoint.xrecoff);
+		   (uint32) (ControlFile.minRecoveryPoint >> 32),
+		   (uint32) ControlFile.minRecoveryPoint);
 	printf(_("Backup start location:                %X/%X\n"),
-		   ControlFile.backupStartPoint.xlogid,
-		   ControlFile.backupStartPoint.xrecoff);
+		   (uint32) (ControlFile.backupStartPoint >> 32),
+		   (uint32) ControlFile.backupStartPoint);
 	printf(_("Backup end location:                  %X/%X\n"),
-		   ControlFile.backupEndPoint.xlogid,
-		   ControlFile.backupEndPoint.xrecoff);
+		   (uint32) (ControlFile.backupEndPoint >> 32),
+		   (uint32) ControlFile.backupEndPoint);
 	printf(_("End-of-backup record required:        %s\n"),
 		   ControlFile.backupEndRequired ? _("yes") : _("no"));
 	printf(_("Current wal_level setting:            %s\n"),
--- a/src/bin/pg_resetxlog/pg_resetxlog.c
+++ b/src/bin/pg_resetxlog/pg_resetxlog.c
@ -463,8 +463,7 @@ GuessControlValues(void)

 	ControlFile.system_identifier = sysidentifier;

-	ControlFile.checkPointCopy.redo.xlogid = 0;
-	ControlFile.checkPointCopy.redo.xrecoff = SizeOfXLogLongPHD;
+	ControlFile.checkPointCopy.redo = SizeOfXLogLongPHD;
 	ControlFile.checkPointCopy.ThisTimeLineID = 1;
 	ControlFile.checkPointCopy.fullPageWrites = false;
 	ControlFile.checkPointCopy.nextXidEpoch = 0;
@ -611,14 +610,10 @@ RewriteControlFile(void)
 	ControlFile.state = DB_SHUTDOWNED;
 	ControlFile.time = (pg_time_t) time(NULL);
 	ControlFile.checkPoint = ControlFile.checkPointCopy.redo;
-	ControlFile.prevCheckPoint.xlogid = 0;
-	ControlFile.prevCheckPoint.xrecoff = 0;
-	ControlFile.minRecoveryPoint.xlogid = 0;
-	ControlFile.minRecoveryPoint.xrecoff = 0;
-	ControlFile.backupStartPoint.xlogid = 0;
-	ControlFile.backupStartPoint.xrecoff = 0;
-	ControlFile.backupEndPoint.xlogid = 0;
-	ControlFile.backupEndPoint.xrecoff = 0;
+	ControlFile.prevCheckPoint = 0;
+	ControlFile.minRecoveryPoint = 0;
+	ControlFile.backupStartPoint = 0;
+	ControlFile.backupEndPoint = 0;
 	ControlFile.backupEndRequired = false;

 	/*
@ -714,8 +709,7 @@ FindEndOfXLOG(void)
 	 * numbering according to the old xlog seg size.
 	 */
 	segs_per_xlogid = (0x100000000L / ControlFile.xlog_seg_size);
-	newXlogSegNo = ((uint64) ControlFile.checkPointCopy.redo.xlogid) * segs_per_xlogid
-		+ (ControlFile.checkPointCopy.redo.xrecoff / ControlFile.xlog_seg_size);
+	newXlogSegNo = ControlFile.checkPointCopy.redo / ControlFile.xlog_seg_size;

 	/*
 	 * Scan the pg_xlog directory to find existing WAL segment files. We
@ -919,10 +913,7 @@ WriteEmptyXLOG(void)
 	page->xlp_magic = XLOG_PAGE_MAGIC;
 	page->xlp_info = XLP_LONG_HEADER;
 	page->xlp_tli = ControlFile.checkPointCopy.ThisTimeLineID;
-	page->xlp_pageaddr.xlogid =
-		ControlFile.checkPointCopy.redo.xlogid;
-	page->xlp_pageaddr.xrecoff =
-		ControlFile.checkPointCopy.redo.xrecoff - SizeOfXLogLongPHD;
+	page->xlp_pageaddr = ControlFile.checkPointCopy.redo - SizeOfXLogLongPHD;
 	longpage = (XLogLongPageHeader) page;
 	longpage->xlp_sysid = ControlFile.system_identifier;
 	longpage->xlp_seg_size = XLogSegSize;
@ -930,8 +921,7 @@ WriteEmptyXLOG(void)

 	/* Insert the initial checkpoint record */
 	record = (XLogRecord *) ((char *) page + SizeOfXLogLongPHD);
-	record->xl_prev.xlogid = 0;
-	record->xl_prev.xrecoff = 0;
+	record->xl_prev = 0;
 	record->xl_xid = InvalidTransactionId;
 	record->xl_tot_len = SizeOfXLogRecord + sizeof(CheckPoint);
 	record->xl_len = sizeof(CheckPoint);
--- a/src/include/access/transam.h
+++ b/src/include/access/transam.h
@ -139,10 +139,6 @@ extern bool TransactionStartedDuringRecovery(void);
 /* in transam/varsup.c */
 extern PGDLLIMPORT VariableCache ShmemVariableCache;

-/* in transam/transam.c */
-extern const XLogRecPtr InvalidXLogRecPtr;
-
-
 /*
 * prototypes for functions in transam/transam.c
 */
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@ -51,7 +51,7 @@ typedef struct BkpBlock
 /*
 * Each page of XLOG file has a header like this:
 */
-#define XLOG_PAGE_MAGIC 0xD074	/* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD075	/* can be used as WAL version indicator */

 typedef struct XLogPageHeaderData
 {
@ -113,10 +113,7 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader;
 #define XLogSegmentsPerXLogId	(0x100000000L / XLOG_SEG_SIZE)

 #define XLogSegNoOffsetToRecPtr(segno, offset, dest) \
-	do {	\
-		(dest).xlogid = (segno) / XLogSegmentsPerXLogId;				\
-		(dest).xrecoff = ((segno) % XLogSegmentsPerXLogId) * XLOG_SEG_SIZE + (offset); \
-	} while (0)
+		(dest) = (segno) * XLOG_SEG_SIZE + (offset)

 /*
 * Macros for manipulating XLOG pointers
@ -125,8 +122,8 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader;
 /* Align a record pointer to next page */
 #define NextLogPage(recptr) \
 	do {	\
-		if ((recptr).xrecoff % XLOG_BLCKSZ != 0)	\
-			XLByteAdvance(recptr, (XLOG_BLCKSZ - (recptr).xrecoff % XLOG_BLCKSZ)); \
+		if ((recptr) % XLOG_BLCKSZ != 0)	\
+			XLByteAdvance(recptr, (XLOG_BLCKSZ - (recptr) % XLOG_BLCKSZ)); \
 	} while (0)

 /*
@ -135,14 +132,13 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader;
 * For XLByteToSeg, do the computation at face value.  For XLByteToPrevSeg,
 * a boundary byte is taken to be in the previous segment.	This is suitable
 * for deciding which segment to write given a pointer to a record end,
- * for example.  (We can assume xrecoff is not zero, since no valid recptr
- * can have that.)
+ * for example.
 */
 #define XLByteToSeg(xlrp, logSegNo)	\
-	logSegNo = ((uint64) (xlrp).xlogid * XLogSegmentsPerXLogId) + (xlrp).xrecoff / XLogSegSize
+	logSegNo = (xlrp) / XLogSegSize

 #define XLByteToPrevSeg(xlrp, logSegNo)	\
-	logSegNo = ((uint64) (xlrp).xlogid * XLogSegmentsPerXLogId) + ((xlrp).xrecoff - 1) / XLogSegSize
+	logSegNo = ((xlrp) - 1) / XLogSegSize

 /*
 * Is an XLogRecPtr within a particular XLOG segment?
@ -151,20 +147,15 @@ typedef XLogLongPageHeaderData *XLogLongPageHeader;
 * a boundary byte is taken to be in the previous segment.
 */
 #define XLByteInSeg(xlrp, logSegNo)	\
-	(((xlrp).xlogid) == (logSegNo) / XLogSegmentsPerXLogId &&			\
-	 ((xlrp).xrecoff / XLogSegSize) == (logSegNo) % XLogSegmentsPerXLogId)
+	(((xlrp) / XLogSegSize) == (logSegNo))

 #define XLByteInPrevSeg(xlrp, logSegNo)	\
-	(((xlrp).xrecoff == 0) ?											\
-		(((xlrp).xlogid - 1) == (logSegNo) / XLogSegmentsPerXLogId && \
-		 ((uint32) 0xffffffff) / XLogSegSize == (logSegNo) % XLogSegmentsPerXLogId) : \
-		((xlrp).xlogid) == (logSegNo) / XLogSegmentsPerXLogId &&	\
-		 (((xlrp).xrecoff - 1) / XLogSegSize) == (logSegNo) % XLogSegmentsPerXLogId)
-
-/* Check if an xrecoff value is in a plausible range */
-#define XRecOffIsValid(xrecoff) \
-		((xrecoff) % XLOG_BLCKSZ >= SizeOfXLogShortPHD && \
-		(XLOG_BLCKSZ - (xrecoff) % XLOG_BLCKSZ) >= SizeOfXLogRecord)
+	((((xlrp) - 1) / XLogSegSize) == (logSegNo))
+
+/* Check if an XLogRecPtr value is in a plausible range */
+#define XRecOffIsValid(xlrp) \
+		((xlrp) % XLOG_BLCKSZ >= SizeOfXLogShortPHD && \
+		 (XLOG_BLCKSZ - (xlrp) % XLOG_BLCKSZ) >= SizeOfXLogRecord)

 /*
 * The XLog directory and control file (relative to $PGDATA)
--- a/src/include/access/xlogdefs.h
+++ b/src/include/access/xlogdefs.h
@ -17,55 +17,30 @@
 /*
 * Pointer to a location in the XLOG.  These pointers are 64 bits wide,
 * because we don't want them ever to overflow.
- *
- * NOTE: xrecoff == 0 is used to indicate an invalid pointer.  This is OK
- * because we use page headers in the XLOG, so no XLOG record can start
- * right at the beginning of a file.
- *
- * NOTE: the "log file number" is somewhat misnamed, since the actual files
- * making up the XLOG are much smaller than 4Gb.  Each actual file is an
- * XLogSegSize-byte "segment" of a logical log file having the indicated
- * xlogid.	The log file number and segment number together identify a
- * physical XLOG file.	Segment number and offset within the physical file
- * are computed from xrecoff div and mod XLogSegSize.
 */
-typedef struct XLogRecPtr
-{
-	uint32		xlogid;			/* log file #, 0 based */
-	uint32		xrecoff;		/* byte offset of location in log file */
-} XLogRecPtr;
-
-#define XLogRecPtrIsInvalid(r)	((r).xrecoff == 0)
+typedef uint64 XLogRecPtr;

+/*
+ * Zero is used indicate an invalid pointer. Bootstrap skips the first possible
+ * WAL segment, initializing the first WAL page at XLOG_SEG_SIZE, so no XLOG
+ * record can begin at zero.
+ */
+#define InvalidXLogRecPtr	0
+#define XLogRecPtrIsInvalid(r)	((r) == InvalidXLogRecPtr)

 /*
 * Macros for comparing XLogRecPtrs
- *
- * Beware of passing expressions with side-effects to these macros,
- * since the arguments may be evaluated multiple times.
 */
-#define XLByteLT(a, b)		\
-			((a).xlogid < (b).xlogid || \
-			 ((a).xlogid == (b).xlogid && (a).xrecoff < (b).xrecoff))
-
-#define XLByteLE(a, b)		\
-			((a).xlogid < (b).xlogid || \
-			 ((a).xlogid == (b).xlogid && (a).xrecoff <= (b).xrecoff))
-
-#define XLByteEQ(a, b)		\
-			((a).xlogid == (b).xlogid && (a).xrecoff == (b).xrecoff)
+#define XLByteLT(a, b)		((a) < (b))
+#define XLByteLE(a, b)		((a) <= (b))
+#define XLByteEQ(a, b)		((a) == (b))


 /*
 * Macro for advancing a record pointer by the specified number of bytes.
 */
 #define XLByteAdvance(recptr, nbytes)						\
-	do {													\
-		uint32 oldxrecoff = (recptr).xrecoff;				\
-		(recptr).xrecoff += nbytes;							\
-		if ((recptr).xrecoff < oldxrecoff)					\
-			(recptr).xlogid += 1;		/* xrecoff wrapped around */	\
-	} while (0)
+		(recptr) += nbytes									\

 /*
 * XLogSegNo - physical log file sequence number.
--- a/src/include/catalog/pg_control.h
+++ b/src/include/catalog/pg_control.h
@ -21,7 +21,7 @@


 /* Version identifier for this pg_control format */
-#define PG_CONTROL_VERSION	922
+#define PG_CONTROL_VERSION	931

 /*
 * Body of CheckPoint XLOG records.  This is declared here because we keep
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@ -119,10 +119,18 @@ typedef uint16 LocationIndex;
 * On the high end, we can only support pages up to 32KB because lp_off/lp_len
 * are 15 bits.
 */
+
+/* for historical reasons, the LSN is stored as two 32-bit values. */
+typedef struct
+{
+	uint32		xlogid;			/* high bits */
+	uint32		xrecoff;		/* low bits */
+} PageXLogRecPtr;
+
 typedef struct PageHeaderData
 {
 	/* XXX LSN is member of *any* block, not only page-organized ones */
-	XLogRecPtr	pd_lsn;			/* LSN: next byte after last byte of xlog
+	PageXLogRecPtr	pd_lsn;			/* LSN: next byte after last byte of xlog
 								 * record for last change to this page */
 	uint16		pd_tli;			/* least significant bits of the TimeLineID
 								 * containing the LSN */
@ -314,9 +322,10 @@ typedef PageHeaderData *PageHeader;
 * Additional macros for access to page headers
 */
 #define PageGetLSN(page) \
-	(((PageHeader) (page))->pd_lsn)
+	((uint64) ((PageHeader) (page))->pd_lsn.xlogid << 32 | ((PageHeader) (page))->pd_lsn.xrecoff)
 #define PageSetLSN(page, lsn) \
-	(((PageHeader) (page))->pd_lsn = (lsn))
+	(((PageHeader) (page))->pd_lsn.xlogid = (uint32) ((lsn) >> 32),	\
+	 ((PageHeader) (page))->pd_lsn.xrecoff = (uint32) (lsn))

 /* NOTE: only the 16 least significant bits are stored */
 #define PageGetTLI(page) \