Don't use O_SYNC or similar when opening signal file to fsync it.

hlinnaka · hlinnaka · commit e9f5a0681cb9 · 2021-07-31T09:36:11.000+03:00
No need to use get_sync_bit() when we're calling pg_fsync() on the file. We're not writing to the files, so it doesn't make any difference in practice, but seems less surprising this way. Reviewed-by: Andres Freund Discussion: https://www.postgresql.org/message-id/b3b71061-4919-e882-4857-27e370ab134a%40iki.fi
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -5484,7 +5484,7 @@ readRecoverySignalFile(void)
 	{
 		int			fd;
 
-		fd = BasicOpenFilePerm(STANDBY_SIGNAL_FILE, O_RDWR | PG_BINARY | get_sync_bit(sync_method),
+		fd = BasicOpenFilePerm(STANDBY_SIGNAL_FILE, O_RDWR | PG_BINARY,
 							   S_IRUSR | S_IWUSR);
 		if (fd >= 0)
 		{
@@ -5497,7 +5497,7 @@ readRecoverySignalFile(void)
 	{
 		int			fd;
 
-		fd = BasicOpenFilePerm(RECOVERY_SIGNAL_FILE, O_RDWR | PG_BINARY | get_sync_bit(sync_method),
+		fd = BasicOpenFilePerm(RECOVERY_SIGNAL_FILE, O_RDWR | PG_BINARY,
 							   S_IRUSR | S_IWUSR);
 		if (fd >= 0)
 		{

Original file line number	Diff line number	Diff line change
`@@ -5484,7 +5484,7 @@ readRecoverySignalFile(void)`
`5484`	`5484`	`{`
`5485`	`5485`	`int fd;`
`5486`	`5486`
`5487`		`- fd = BasicOpenFilePerm(STANDBY_SIGNAL_FILE, O_RDWR \| PG_BINARY \| get_sync_bit(sync_method),`
	`5487`	`+ fd = BasicOpenFilePerm(STANDBY_SIGNAL_FILE, O_RDWR \| PG_BINARY,`
`5488`	`5488`	`S_IRUSR \| S_IWUSR);`
`5489`	`5489`	`if (fd >= 0)`
`5490`	`5490`	`{`
`@@ -5497,7 +5497,7 @@ readRecoverySignalFile(void)`
`5497`	`5497`	`{`
`5498`	`5498`	`int fd;`
`5499`	`5499`
`5500`		`- fd = BasicOpenFilePerm(RECOVERY_SIGNAL_FILE, O_RDWR \| PG_BINARY \| get_sync_bit(sync_method),`
	`5500`	`+ fd = BasicOpenFilePerm(RECOVERY_SIGNAL_FILE, O_RDWR \| PG_BINARY,`
`5501`	`5501`	`S_IRUSR \| S_IWUSR);`
`5502`	`5502`	`if (fd >= 0)`
`5503`	`5503`	`{`