Remove more volatile qualifiers.

Prior to commit 0709b7ee72e4bc71ad07b7120acd117265ab51d0, access to
variables within a spinlock-protected critical section had to be done
through a volatile pointer, but that should no longer be necessary.
This continues work begun in df4077cda2eae3eb4a5cf387da0c1e7616e73204
and 6ba4ecbf477e0b25dd7bde1b0c4e07fc2da19348.

Thomas Munro and Michael Paquier

6 files changed, 108 insertions, 182 deletions

diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 3b3a09ef886..dc5b8561550 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -288,13 +288,10 @@ CheckpointerMain(void)
 		/* Warn any waiting backends that the checkpoint failed. */
 		if (ckpt_active)
 		{
-			/* use volatile pointer to prevent code rearrangement */
-			volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
-
-			SpinLockAcquire(&cps->ckpt_lck);
-			cps->ckpt_failed++;
-			cps->ckpt_done = cps->ckpt_started;
-			SpinLockRelease(&cps->ckpt_lck);
+			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+			CheckpointerShmem->ckpt_failed++;
+			CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
+			SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 			ckpt_active = false;
 		}
@@ -428,9 +425,6 @@ CheckpointerMain(void)
 			bool		ckpt_performed = false;
 			bool		do_restartpoint;
 
-			/* use volatile pointer to prevent code rearrangement */
-			volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
-
 			/*
 			 * Check if we should perform a checkpoint or a restartpoint. As a
 			 * side-effect, RecoveryInProgress() initializes TimeLineID if
@@ -443,11 +437,11 @@ CheckpointerMain(void)
 			 * checkpoint we should perform, and increase the started-counter
 			 * to acknowledge that we've started a new checkpoint.
 			 */
-			SpinLockAcquire(&cps->ckpt_lck);
-			flags |= cps->ckpt_flags;
-			cps->ckpt_flags = 0;
-			cps->ckpt_started++;
-			SpinLockRelease(&cps->ckpt_lck);
+			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+			flags |= CheckpointerShmem->ckpt_flags;
+			CheckpointerShmem->ckpt_flags = 0;
+			CheckpointerShmem->ckpt_started++;
+			SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 			/*
 			 * The end-of-recovery checkpoint is a real checkpoint that's
@@ -505,9 +499,9 @@ CheckpointerMain(void)
 			/*
 			 * Indicate checkpoint completion to any waiting backends.
 			 */
-			SpinLockAcquire(&cps->ckpt_lck);
-			cps->ckpt_done = cps->ckpt_started;
-			SpinLockRelease(&cps->ckpt_lck);
+			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+			CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
+			SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 			if (ckpt_performed)
 			{
@@ -957,8 +951,6 @@ CheckpointerShmemInit(void)
 void
 RequestCheckpoint(int flags)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
 	int			ntries;
 	int			old_failed,
 				old_started;
@@ -992,13 +984,13 @@ RequestCheckpoint(int flags)
 	 * a "stronger" request by another backend.  The flag senses must be
 	 * chosen to make this work!
 	 */
-	SpinLockAcquire(&cps->ckpt_lck);
+	SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
 
-	old_failed = cps->ckpt_failed;
-	old_started = cps->ckpt_started;
-	cps->ckpt_flags |= flags;
+	old_failed = CheckpointerShmem->ckpt_failed;
+	old_started = CheckpointerShmem->ckpt_started;
+	CheckpointerShmem->ckpt_flags |= flags;
 
-	SpinLockRelease(&cps->ckpt_lck);
+	SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 	/*
 	 * Send signal to request checkpoint.  It's possible that the checkpointer
@@ -1046,9 +1038,9 @@ RequestCheckpoint(int flags)
 		/* Wait for a new checkpoint to start. */
 		for (;;)
 		{
-			SpinLockAcquire(&cps->ckpt_lck);
-			new_started = cps->ckpt_started;
-			SpinLockRelease(&cps->ckpt_lck);
+			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+			new_started = CheckpointerShmem->ckpt_started;
+			SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 			if (new_started != old_started)
 				break;
@@ -1064,10 +1056,10 @@ RequestCheckpoint(int flags)
 		{
 			int			new_done;
 
-			SpinLockAcquire(&cps->ckpt_lck);
-			new_done = cps->ckpt_done;
-			new_failed = cps->ckpt_failed;
-			SpinLockRelease(&cps->ckpt_lck);
+			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+			new_done = CheckpointerShmem->ckpt_done;
+			new_failed = CheckpointerShmem->ckpt_failed;
+			SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 			if (new_done - new_started >= 0)
 				break;
@@ -1368,15 +1360,13 @@ UpdateSharedMemoryConfig(void)
 bool
 FirstCallSinceLastCheckpoint(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
 	static int	ckpt_done = 0;
 	int			new_done;
 	bool		FirstCall = false;
 
-	SpinLockAcquire(&cps->ckpt_lck);
-	new_done = cps->ckpt_done;
-	SpinLockRelease(&cps->ckpt_lck);
+	SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
+	new_done = CheckpointerShmem->ckpt_done;
+	SpinLockRelease(&CheckpointerShmem->ckpt_lck);
 
 	if (new_done != ckpt_done)
 		FirstCall = true;
diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c
index 5a07e1d9a69..1ce90811cc8 100644
--- a/src/backend/replication/logical/logical.c
+++ b/src/backend/replication/logical/logical.c
@@ -848,16 +848,13 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
 		bool		updated_xmin = false;
 		bool		updated_restart = false;
 
-		/* use volatile pointer to prevent code rearrangement */
-		volatile ReplicationSlot *slot = MyReplicationSlot;
+		SpinLockAcquire(&MyReplicationSlot->mutex);
 
-		SpinLockAcquire(&slot->mutex);
-
-		slot->data.confirmed_flush = lsn;
+		MyReplicationSlot->data.confirmed_flush = lsn;
 
 		/* if were past the location required for bumping xmin, do so */
-		if (slot->candidate_xmin_lsn != InvalidXLogRecPtr &&
-			slot->candidate_xmin_lsn <= lsn)
+		if (MyReplicationSlot->candidate_xmin_lsn != InvalidXLogRecPtr &&
+			MyReplicationSlot->candidate_xmin_lsn <= lsn)
 		{
 			/*
 			 * We have to write the changed xmin to disk *before* we change
@@ -868,28 +865,28 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
 			 * ->effective_xmin once the new state is synced to disk. After a
 			 * crash ->effective_xmin is set to ->xmin.
 			 */
-			if (TransactionIdIsValid(slot->candidate_catalog_xmin) &&
-				slot->data.catalog_xmin != slot->candidate_catalog_xmin)
+			if (TransactionIdIsValid(MyReplicationSlot->candidate_catalog_xmin) &&
+				MyReplicationSlot->data.catalog_xmin != MyReplicationSlot->candidate_catalog_xmin)
 			{
-				slot->data.catalog_xmin = slot->candidate_catalog_xmin;
-				slot->candidate_catalog_xmin = InvalidTransactionId;
-				slot->candidate_xmin_lsn = InvalidXLogRecPtr;
+				MyReplicationSlot->data.catalog_xmin = MyReplicationSlot->candidate_catalog_xmin;
+				MyReplicationSlot->candidate_catalog_xmin = InvalidTransactionId;
+				MyReplicationSlot->candidate_xmin_lsn = InvalidXLogRecPtr;
 				updated_xmin = true;
 			}
 		}
 
-		if (slot->candidate_restart_valid != InvalidXLogRecPtr &&
-			slot->candidate_restart_valid <= lsn)
+		if (MyReplicationSlot->candidate_restart_valid != InvalidXLogRecPtr &&
+			MyReplicationSlot->candidate_restart_valid <= lsn)
 		{
-			Assert(slot->candidate_restart_lsn != InvalidXLogRecPtr);
+			Assert(MyReplicationSlot->candidate_restart_lsn != InvalidXLogRecPtr);
 
-			slot->data.restart_lsn = slot->candidate_restart_lsn;
-			slot->candidate_restart_lsn = InvalidXLogRecPtr;
-			slot->candidate_restart_valid = InvalidXLogRecPtr;
+			MyReplicationSlot->data.restart_lsn = MyReplicationSlot->candidate_restart_lsn;
+			MyReplicationSlot->candidate_restart_lsn = InvalidXLogRecPtr;
+			MyReplicationSlot->candidate_restart_valid = InvalidXLogRecPtr;
 			updated_restart = true;
 		}
 
-		SpinLockRelease(&slot->mutex);
+		SpinLockRelease(&MyReplicationSlot->mutex);
 
 		/* first write new xmin to disk, so we know whats up after a crash */
 		if (updated_xmin || updated_restart)
@@ -907,9 +904,9 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
 		 */
 		if (updated_xmin)
 		{
-			SpinLockAcquire(&slot->mutex);
-			slot->effective_catalog_xmin = slot->data.catalog_xmin;
-			SpinLockRelease(&slot->mutex);
+			SpinLockAcquire(&MyReplicationSlot->mutex);
+			MyReplicationSlot->effective_catalog_xmin = MyReplicationSlot->data.catalog_xmin;
+			SpinLockRelease(&MyReplicationSlot->mutex);
 
 			ReplicationSlotsComputeRequiredXmin(false);
 			ReplicationSlotsComputeRequiredLSN();
@@ -917,10 +914,8 @@ LogicalConfirmReceivedLocation(XLogRecPtr lsn)
 	}
 	else
 	{
-		volatile ReplicationSlot *slot = MyReplicationSlot;
-
-		SpinLockAcquire(&slot->mutex);
-		slot->data.confirmed_flush = lsn;
-		SpinLockRelease(&slot->mutex);
+		SpinLockAcquire(&MyReplicationSlot->mutex);
+		MyReplicationSlot->data.confirmed_flush = lsn;
+		SpinLockRelease(&MyReplicationSlot->mutex);
 	}
 }
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index a4b86e039e3..92ec6326de1 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -288,15 +288,11 @@ ReplicationSlotCreate(const char *name, bool db_specific,
 	slot->in_use = true;
 
 	/* We can now mark the slot active, and that makes it our slot. */
-	{
-		volatile ReplicationSlot *vslot = slot;
-
-		SpinLockAcquire(&slot->mutex);
-		Assert(vslot->active_pid == 0);
-		vslot->active_pid = MyProcPid;
-		SpinLockRelease(&slot->mutex);
-		MyReplicationSlot = slot;
-	}
+	SpinLockAcquire(&slot->mutex);
+	Assert(slot->active_pid == 0);
+	slot->active_pid = MyProcPid;
+	SpinLockRelease(&slot->mutex);
+	MyReplicationSlot = slot;
 
 	LWLockRelease(ReplicationSlotControlLock);
 
@@ -329,12 +325,10 @@ ReplicationSlotAcquire(const char *name)
 
 		if (s->in_use && strcmp(name, NameStr(s->data.name)) == 0)
 		{
-			volatile ReplicationSlot *vslot = s;
-
 			SpinLockAcquire(&s->mutex);
-			active_pid = vslot->active_pid;
+			active_pid = s->active_pid;
 			if (active_pid == 0)
-				vslot->active_pid = MyProcPid;
+				s->active_pid = MyProcPid;
 			SpinLockRelease(&s->mutex);
 			slot = s;
 			break;
@@ -380,10 +374,8 @@ ReplicationSlotRelease(void)
 	else
 	{
 		/* Mark slot inactive.  We're not freeing it, just disconnecting. */
-		volatile ReplicationSlot *vslot = slot;
-
 		SpinLockAcquire(&slot->mutex);
-		vslot->active_pid = 0;
+		slot->active_pid = 0;
 		SpinLockRelease(&slot->mutex);
 	}
 
@@ -459,11 +451,10 @@ ReplicationSlotDropAcquired(void)
 	}
 	else
 	{
-		volatile ReplicationSlot *vslot = slot;
 		bool		fail_softly = slot->data.persistency == RS_EPHEMERAL;
 
 		SpinLockAcquire(&slot->mutex);
-		vslot->active_pid = 0;
+		slot->active_pid = 0;
 		SpinLockRelease(&slot->mutex);
 
 		ereport(fail_softly ? WARNING : ERROR,
@@ -533,16 +524,13 @@ ReplicationSlotSave(void)
 void
 ReplicationSlotMarkDirty(void)
 {
+	ReplicationSlot *slot = MyReplicationSlot;
 	Assert(MyReplicationSlot != NULL);
 
-	{
-		volatile ReplicationSlot *vslot = MyReplicationSlot;
-
-		SpinLockAcquire(&vslot->mutex);
-		MyReplicationSlot->just_dirtied = true;
-		MyReplicationSlot->dirty = true;
-		SpinLockRelease(&vslot->mutex);
-	}
+	SpinLockAcquire(&slot->mutex);
+	MyReplicationSlot->just_dirtied = true;
+	MyReplicationSlot->dirty = true;
+	SpinLockRelease(&slot->mutex);
 }
 
 /*
@@ -557,13 +545,9 @@ ReplicationSlotPersist(void)
 	Assert(slot != NULL);
 	Assert(slot->data.persistency != RS_PERSISTENT);
 
-	{
-		volatile ReplicationSlot *vslot = slot;
-
-		SpinLockAcquire(&slot->mutex);
-		vslot->data.persistency = RS_PERSISTENT;
-		SpinLockRelease(&slot->mutex);
-	}
+	SpinLockAcquire(&slot->mutex);
+	slot->data.persistency = RS_PERSISTENT;
+	SpinLockRelease(&slot->mutex);
 
 	ReplicationSlotMarkDirty();
 	ReplicationSlotSave();
@@ -593,14 +577,10 @@ ReplicationSlotsComputeRequiredXmin(bool already_locked)
 		if (!s->in_use)
 			continue;
 
-		{
-			volatile ReplicationSlot *vslot = s;
-
-			SpinLockAcquire(&s->mutex);
-			effective_xmin = vslot->effective_xmin;
-			effective_catalog_xmin = vslot->effective_catalog_xmin;
-			SpinLockRelease(&s->mutex);
-		}
+		SpinLockAcquire(&s->mutex);
+		effective_xmin = s->effective_xmin;
+		effective_catalog_xmin = s->effective_catalog_xmin;
+		SpinLockRelease(&s->mutex);
 
 		/* check the data xmin */
 		if (TransactionIdIsValid(effective_xmin) &&
@@ -641,13 +621,9 @@ ReplicationSlotsComputeRequiredLSN(void)
 		if (!s->in_use)
 			continue;
 
-		{
-			volatile ReplicationSlot *vslot = s;
-
-			SpinLockAcquire(&s->mutex);
-			restart_lsn = vslot->data.restart_lsn;
-			SpinLockRelease(&s->mutex);
-		}
+		SpinLockAcquire(&s->mutex);
+		restart_lsn = s->data.restart_lsn;
+		SpinLockRelease(&s->mutex);
 
 		if (restart_lsn != InvalidXLogRecPtr &&
 			(min_required == InvalidXLogRecPtr ||
@@ -684,7 +660,7 @@ ReplicationSlotsComputeLogicalRestartLSN(void)
 
 	for (i = 0; i < max_replication_slots; i++)
 	{
-		volatile ReplicationSlot *s;
+		ReplicationSlot *s;
 		XLogRecPtr	restart_lsn;
 
 		s = &ReplicationSlotCtl->replication_slots[i];
@@ -733,7 +709,7 @@ ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive)
 	LWLockAcquire(ReplicationSlotControlLock, LW_SHARED);
 	for (i = 0; i < max_replication_slots; i++)
 	{
-		volatile ReplicationSlot *s;
+		ReplicationSlot *s;
 
 		s = &ReplicationSlotCtl->replication_slots[i];
 
@@ -1023,14 +999,10 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
 	bool		was_dirty;
 
 	/* first check whether there's something to write out */
-	{
-		volatile ReplicationSlot *vslot = slot;
-
-		SpinLockAcquire(&vslot->mutex);
-		was_dirty = vslot->dirty;
-		vslot->just_dirtied = false;
-		SpinLockRelease(&vslot->mutex);
-	}
+	SpinLockAcquire(&slot->mutex);
+	was_dirty = slot->dirty;
+	slot->just_dirtied = false;
+	SpinLockRelease(&slot->mutex);
 
 	/* and don't do anything if there's nothing to write */
 	if (!was_dirty)
@@ -1124,14 +1096,10 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel)
 	 * Successfully wrote, unset dirty bit, unless somebody dirtied again
 	 * already.
 	 */
-	{
-		volatile ReplicationSlot *vslot = slot;
-
-		SpinLockAcquire(&vslot->mutex);
-		if (!vslot->just_dirtied)
-			vslot->dirty = false;
-		SpinLockRelease(&vslot->mutex);
-	}
+	SpinLockAcquire(&slot->mutex);
+	if (!slot->just_dirtied)
+		slot->dirty = false;
+	SpinLockRelease(&slot->mutex);
 
 	LWLockRelease(slot->io_in_progress_lock);
 }
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 41e57f24397..183a3a553db 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -192,9 +192,7 @@ WalReceiverMain(void)
 	TimeLineID	startpointTLI;
 	TimeLineID	primaryTLI;
 	bool		first_stream;
-
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	TimestampTz last_recv_timestamp;
 	bool		ping_sent;
 
@@ -559,8 +557,7 @@ WalReceiverMain(void)
 static void
 WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	int			state;
 
 	SpinLockAcquire(&walrcv->mutex);
@@ -693,8 +690,7 @@ WalRcvFetchTimeLineHistoryFiles(TimeLineID first, TimeLineID last)
 static void
 WalRcvDie(int code, Datum arg)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 
 	/* Ensure that all WAL records received are flushed to disk */
 	XLogWalRcvFlush(true);
@@ -974,8 +970,7 @@ XLogWalRcvFlush(bool dying)
 {
 	if (LogstreamResult.Flush < LogstreamResult.Write)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalRcvData *walrcv = WalRcv;
+		WalRcvData *walrcv = WalRcv;
 
 		issue_xlog_fsync(recvFile, recvSegNo);
 
@@ -1179,8 +1174,7 @@ XLogWalRcvSendHSFeedback(bool immed)
 static void
 ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 
 	TimestampTz lastMsgReceiptTime = GetCurrentTimestamp();
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index f77a790fd87..4452f25d72a 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -72,8 +72,7 @@ WalRcvShmemInit(void)
 bool
 WalRcvRunning(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	WalRcvState state;
 	pg_time_t	startTime;
 
@@ -118,8 +117,7 @@ WalRcvRunning(void)
 bool
 WalRcvStreaming(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	WalRcvState state;
 	pg_time_t	startTime;
 
@@ -165,8 +163,7 @@ WalRcvStreaming(void)
 void
 ShutdownWalRcv(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	pid_t		walrcvpid = 0;
 
 	/*
@@ -227,8 +224,7 @@ void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 					 const char *slotname)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
 	pg_time_t	now = (pg_time_t) time(NULL);
 
@@ -298,8 +294,7 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 XLogRecPtr
 GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 	XLogRecPtr	recptr;
 
 	SpinLockAcquire(&walrcv->mutex);
@@ -320,9 +315,7 @@ GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI)
 int
 GetReplicationApplyDelay(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
-
+	WalRcvData *walrcv = WalRcv;
 	XLogRecPtr	receivePtr;
 	XLogRecPtr	replayPtr;
 
@@ -359,8 +352,7 @@ GetReplicationApplyDelay(void)
 int
 GetReplicationTransferLatency(void)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalRcvData *walrcv = WalRcv;
+	WalRcvData *walrcv = WalRcv;
 
 	TimestampTz lastMsgSendTime;
 	TimestampTz lastMsgReceiptTime;
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c95fe75a721..c6043cd3ce4 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -641,8 +641,7 @@ StartReplication(StartReplicationCmd *cmd)
 
 		/* Initialize shared memory status, too */
 		{
-			/* use volatile pointer to prevent code rearrangement */
-			volatile WalSnd *walsnd = MyWalSnd;
+			WalSnd *walsnd = MyWalSnd;
 
 			SpinLockAcquire(&walsnd->mutex);
 			walsnd->sentPtr = sentPtr;
@@ -990,8 +989,7 @@ StartLogicalReplication(StartReplicationCmd *cmd)
 
 	/* Also update the sent position status in shared memory */
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = MyWalSnd;
+		WalSnd *walsnd = MyWalSnd;
 
 		SpinLockAcquire(&walsnd->mutex);
 		walsnd->sentPtr = MyReplicationSlot->data.restart_lsn;
@@ -1494,9 +1492,7 @@ static void
 PhysicalConfirmReceivedLocation(XLogRecPtr lsn)
 {
 	bool		changed = false;
-
-	/* use volatile pointer to prevent code rearrangement */
-	volatile ReplicationSlot *slot = MyReplicationSlot;
+	ReplicationSlot *slot = MyReplicationSlot;
 
 	Assert(lsn != InvalidXLogRecPtr);
 	SpinLockAcquire(&slot->mutex);
@@ -1554,8 +1550,7 @@ ProcessStandbyReplyMessage(void)
 	 * standby.
 	 */
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = MyWalSnd;
+		WalSnd *walsnd = MyWalSnd;
 
 		SpinLockAcquire(&walsnd->mutex);
 		walsnd->write = writePtr;
@@ -1584,7 +1579,7 @@ static void
 PhysicalReplicationSlotNewXmin(TransactionId feedbackXmin)
 {
 	bool		changed = false;
-	volatile ReplicationSlot *slot = MyReplicationSlot;
+	ReplicationSlot *slot = MyReplicationSlot;
 
 	SpinLockAcquire(&slot->mutex);
 	MyPgXact->xmin = InvalidTransactionId;
@@ -1934,8 +1929,7 @@ InitWalSenderSlot(void)
 	 */
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
+		WalSnd *walsnd = &WalSndCtl->walsnds[i];
 
 		SpinLockAcquire(&walsnd->mutex);
 
@@ -2145,8 +2139,7 @@ retry:
 	 */
 	if (am_cascading_walsender)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = MyWalSnd;
+		WalSnd *walsnd = MyWalSnd;
 		bool		reload;
 
 		SpinLockAcquire(&walsnd->mutex);
@@ -2384,8 +2377,7 @@ XLogSendPhysical(void)
 
 	/* Update shared memory status */
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = MyWalSnd;
+		WalSnd *walsnd = MyWalSnd;
 
 		SpinLockAcquire(&walsnd->mutex);
 		walsnd->sentPtr = sentPtr;
@@ -2447,8 +2439,7 @@ XLogSendLogical(void)
 
 	/* Update shared memory status */
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = MyWalSnd;
+		WalSnd *walsnd = MyWalSnd;
 
 		SpinLockAcquire(&walsnd->mutex);
 		walsnd->sentPtr = sentPtr;
@@ -2539,8 +2530,7 @@ WalSndRqstFileReload(void)
 
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
+		WalSnd *walsnd = &WalSndCtl->walsnds[i];
 
 		if (walsnd->pid == 0)
 			continue;
@@ -2692,8 +2682,7 @@ WalSndWakeup(void)
 void
 WalSndSetState(WalSndState state)
 {
-	/* use volatile pointer to prevent code rearrangement */
-	volatile WalSnd *walsnd = MyWalSnd;
+	WalSnd *walsnd = MyWalSnd;
 
 	Assert(am_walsender);
 
@@ -2777,8 +2766,7 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
 
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
+		WalSnd *walsnd = &WalSndCtl->walsnds[i];
 		XLogRecPtr	sentPtr;
 		XLogRecPtr	write;
 		XLogRecPtr	flush;
@@ -2934,8 +2922,7 @@ GetOldestWALSendPointer(void)
 
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		/* use volatile pointer to prevent code rearrangement */
-		volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
+		WalSnd *walsnd = &WalSndCtl->walsnds[i];
 		XLogRecPtr	recptr;
 
 		if (walsnd->pid == 0)