Switch pg_test_fsync to use binary mode on Windows

pg_test_fsync has always opened files using the text mode on Windows, as
this is the default mode used if not enforced by _setmode().

This fixes a failure when running pg_test_fsync down to 12 because
O_DSYNC and the text mode are not able to work together nicely.  We
fixed the handling of O_DSYNC in 12~ for the tool by switching to the
concurrent-safe version of fopen() in src/port/ with 0ba06e0b.  And
40cfe860, by enforcing the text mode for compatibility reasons if O_TEXT
or O_BINARY are not specified by the caller, broke pg_test_fsync.  For
all versions, this avoids any translation overhead, and pg_test_fsync
should test binary writes, so it is a gain in all cases.

Note that O_DSYNC is still not handled correctly in ~11, leading to
pg_test_fsync to show insanely high numbers for open_datasync() (using
this property it is easy to notice that the binary mode is much
faster).  This would require a backpatch of 0ba06e0b and 40cfe860, which
could potentially break existing applications, so this is left out.

There are no TAP tests for this tool yet, so I have checked all builds
manually using MSVC.  We could invent a new option to run a single
transaction instead of using a duration of 1s to make the tests a
maximum short, but this is left as future work.

Thanks to Bruce Momjian for the discussion.

Reported-by: Jeff Janes
Author: Michael Paquier
Discussion: https://postgr.es/m/16526-279ded30a230d275@postgresql.org
Backpatch-through: 9.5

src/bin/pg_test_fsync/pg_test_fsync.c

@@ -224,7 +224,7 @@ test_open(void)
 	/*
 	 * test if we can open the target file
 	 */
-	if ((tmpfile = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR)) == -1)
 		die("could not open output file");
 	needs_unlink = 1;
 	if (write(tmpfile, full_buf, DEFAULT_XLOG_SEG_SIZE) !=
@@ -259,7 +259,7 @@ test_sync(int writes_per_op)
 	fflush(stdout);
 
 #ifdef OPEN_DATASYNC_FLAG
-	if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT | PG_BINARY, 0)) == -1)
 	{
 		printf(NA_FORMAT, _("n/a*"));
 		fs_warning = true;
@@ -289,7 +289,7 @@ test_sync(int writes_per_op)
 	fflush(stdout);
 
 #ifdef HAVE_FDATASYNC
-	if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 		die("could not open output file");
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
@@ -313,7 +313,7 @@ test_sync(int writes_per_op)
 	printf(LABEL_FORMAT, "fsync");
 	fflush(stdout);
 
-	if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 		die("could not open output file");
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
@@ -336,7 +336,7 @@ test_sync(int writes_per_op)
 	fflush(stdout);
 
 #ifdef HAVE_FSYNC_WRITETHROUGH
-	if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 		die("could not open output file");
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
@@ -362,7 +362,7 @@ test_sync(int writes_per_op)
 	fflush(stdout);
 
 #ifdef OPEN_SYNC_FLAG
-	if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT | PG_BINARY, 0)) == -1)
 	{
 		printf(NA_FORMAT, _("n/a*"));
 		fs_warning = true;
@@ -429,7 +429,7 @@ test_open_sync(const char *msg, int writes_size)
 	fflush(stdout);
 
 #ifdef OPEN_SYNC_FLAG
-	if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
+	if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT | PG_BINARY, 0)) == -1)
 		printf(NA_FORMAT, _("n/a*"));
 	else
 	{
@@ -477,7 +477,7 @@ test_file_descriptor_sync(void)
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
 	{
-		if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+		if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 			die("could not open output file");
 		if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 			die("write failed");
@@ -489,7 +489,7 @@ test_file_descriptor_sync(void)
 		 * open and close the file again to be consistent with the following
 		 * test
 		 */
-		if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+		if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 			die("could not open output file");
 		close(tmpfile);
 	}
@@ -505,13 +505,13 @@ test_file_descriptor_sync(void)
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
 	{
-		if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+		if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 			die("could not open output file");
 		if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 			die("write failed");
 		close(tmpfile);
 		/* reopen file */
-		if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+		if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 			die("could not open output file");
 		if (fsync(tmpfile) != 0)
 			die("fsync failed");
@@ -536,7 +536,7 @@ test_non_sync(void)
 	START_TIMER;
 	for (ops = 0; alarm_triggered == false; ops++)
 	{
-		if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+		if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 			die("could not open output file");
 		if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
 			die("write failed");