diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d9f2487a96..cd674c3c23 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -233,7 +233,6 @@ extern void ShutdownXLOG(int code, Datum arg);
 extern void CreateCheckPoint(int flags);
 extern bool CreateRestartPoint(int flags);
 extern WALAvailability GetWALAvailability(XLogRecPtr targetLSN);
-extern XLogRecPtr CalculateMaxmumSafeLSN(void);
 extern void XLogPutNextOid(Oid nextOid);
 extern XLogRecPtr XLogRestorePoint(const char *rpName);
 extern void UpdateFullPageWrites(void);