Resurrect -F switch: it controls fsyncs again, though the fsyncs are

mostly just on the WAL logfile nowadays.  But if people want to disable
fsync for performance, why should we say no?

src/backend/access/transam/xlog.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.39 2000/12/03 10:27:26 vadim Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.40 2000/12/08 22:21:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -621,7 +621,7 @@ XLogFlush(XLogRecPtr record)
 		logFile = XLogFileOpen(logId, logSeg, false);
 	}
 
-	if (fsync(logFile) != 0)
+	if (pg_fsync(logFile) != 0)
 		elog(STOP, "fsync(logfile %u seg %u) failed: %m",
 			 logId, logSeg);
 	LgwrResult.Flush = LgwrResult.Write;
@@ -717,7 +717,7 @@ XLogWrite(char *buffer)
 		{
 			if (wcnt > 0)
 			{
-				if (fsync(logFile) != 0)
+				if (pg_fsync(logFile) != 0)
 					elog(STOP, "fsync(logfile %u seg %u) failed: %m",
 						 logId, logSeg);
 				if (LgwrResult.Write.xlogid != logId)
@@ -799,7 +799,7 @@ XLogWrite(char *buffer)
 	if (XLByteLT(LgwrResult.Flush, LgwrRqst.Flush) &&
 		XLByteLE(LgwrRqst.Flush, LgwrResult.Write))
 	{
-		if (fsync(logFile) != 0)
+		if (pg_fsync(logFile) != 0)
 			elog(STOP, "fsync(logfile %u seg %u) failed: %m",
 				 logId, logSeg);
 		LgwrResult.Flush = LgwrResult.Write;
@@ -864,7 +864,7 @@ XLogFileInit(uint32 log, uint32 seg, bool *usexistent)
 		elog(STOP, "write(logfile %u seg %u) failed: %m",
 			 logId, logSeg);
 
-	if (fsync(fd) != 0)
+	if (pg_fsync(fd) != 0)
 		elog(STOP, "fsync(logfile %u seg %u) failed: %m",
 			 logId, logSeg);
 
@@ -1213,7 +1213,7 @@ next_record_is_invalid:;
 	}
 	if (readFile >= 0)
 	{
-		if (fsync(readFile) < 0)
+		if (pg_fsync(readFile) < 0)
 			elog(STOP, "ReadRecord: fsync(logfile %u seg %u) failed: %m",
 				 readId, readSeg);
 		close(readFile);
@@ -1330,7 +1330,7 @@ WriteControlFile(void)
 	if (write(fd, buffer, BLCKSZ) != BLCKSZ)
 		elog(STOP, "WriteControlFile failed to write control file: %m");
 
-	if (fsync(fd) != 0)
+	if (pg_fsync(fd) != 0)
 		elog(STOP, "WriteControlFile failed to fsync control file: %m");
 
 	close(fd);
@@ -1400,7 +1400,7 @@ UpdateControlFile(void)
 	if (write(fd, ControlFile, sizeof(ControlFileData)) != sizeof(ControlFileData))
 		elog(STOP, "write(cntlfile) failed: %m");
 
-	if (fsync(fd) != 0)
+	if (pg_fsync(fd) != 0)
 		elog(STOP, "fsync(cntlfile) failed: %m");
 
 	close(fd);
@@ -1489,7 +1489,7 @@ BootStrapXLOG()
 	if (write(logFile, buffer, BLCKSZ) != BLCKSZ)
 		elog(STOP, "BootStrapXLOG failed to write logfile: %m");
 
-	if (fsync(logFile) != 0)
+	if (pg_fsync(logFile) != 0)
 		elog(STOP, "BootStrapXLOG failed to fsync logfile: %m");
 
 	close(logFile);

src/backend/storage/file/fd.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.68 2000/11/30 08:46:23 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.69 2000/12/08 22:21:32 tgl Exp $
  *
  * NOTES:
  *
@@ -192,6 +192,18 @@ static File fileNameOpenFile(FileName fileName, int fileFlags, int fileMode);
 static char *filepath(char *filename);
 static long pg_nofile(void);
 
+/*
+ * pg_fsync --- same as fsync except does nothing if -F switch was given
+ */
+int
+pg_fsync(int fd)
+{
+	if (enableFsync)
+		return fsync(fd);
+	else
+		return 0;
+}
+
 /*
  * BasicOpenFile --- same as open(2) except can free other FDs if needed
  *

src/include/storage/fd.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: fd.h,v 1.24 2000/11/30 08:46:26 vadim Exp $
+ * $Id: fd.h,v 1.25 2000/12/08 22:21:32 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -70,7 +70,6 @@ extern int	BasicOpenFile(FileName fileName, int fileFlags, int fileMode);
 /* Miscellaneous support routines */
 extern void closeAllVfds(void);
 extern void AtEOXact_Files(void);
-
-#define pg_fsync(fd)	fsync(fd)
+extern int	pg_fsync(int fd);
 
 #endif	 /* FD_H */