Assign InvalidXLogRecPtr instead of MemSet(0)

For consistency.

Author: Andres Freund

src/backend/access/transam/xlog.c

@@ -6393,8 +6393,8 @@ CheckRecoveryConsistency(void)
 		if (XLByteLT(ControlFile->minRecoveryPoint, EndRecPtr))
 			ControlFile->minRecoveryPoint = EndRecPtr;
 
-		MemSet(&ControlFile->backupStartPoint, 0, sizeof(XLogRecPtr));
-		MemSet(&ControlFile->backupEndPoint, 0, sizeof(XLogRecPtr));
+		ControlFile->backupStartPoint = InvalidXLogRecPtr;
+		ControlFile->backupEndPoint = InvalidXLogRecPtr;
 		ControlFile->backupEndRequired = false;
 		UpdateControlFile();
 
@@ -7330,7 +7330,7 @@ CreateCheckPoint(int flags)
 	ControlFile->checkPointCopy = checkPoint;
 	ControlFile->time = (pg_time_t) time(NULL);
 	/* crash recovery should always recover to the end of WAL */
-	MemSet(&ControlFile->minRecoveryPoint, 0, sizeof(XLogRecPtr));
+	ControlFile->minRecoveryPoint = InvalidXLogRecPtr;
 	ControlFile->minRecoveryPointTLI = 0;
 	UpdateControlFile();
 	LWLockRelease(ControlFileLock);
@@ -8161,7 +8161,7 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
 				ControlFile->minRecoveryPoint = lsn;
 				ControlFile->minRecoveryPointTLI = ThisTimeLineID;
 			}
-			MemSet(&ControlFile->backupStartPoint, 0, sizeof(XLogRecPtr));
+			ControlFile->backupStartPoint = InvalidXLogRecPtr;
 			ControlFile->backupEndRequired = false;
 			UpdateControlFile();
 

src/backend/replication/walsender.c

@@ -1115,7 +1115,7 @@ InitWalSenderSlot(void)
 			 * Found a free slot. Reserve it for us.
 			 */
 			walsnd->pid = MyProcPid;
-			MemSet(&walsnd->sentPtr, 0, sizeof(XLogRecPtr));
+			walsnd->sentPtr = InvalidXLogRecPtr;
 			walsnd->state = WALSNDSTATE_STARTUP;
 			SpinLockRelease(&walsnd->mutex);
 			/* don't need the lock anymore */