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Remove O_FSYNC and associated macros.

O_FSYNC was a pre-POSIX way of spelling O_SYNC, supported since commit
9d645fd84c for non-conforming operating systems of the time.  It's not
needed on any modern system.  We can just use standard O_SYNC directly
if it exists (= all targeted systems except Windows), and get rid of our
OPEN_SYNC_FLAG macro.

Similarly for standard O_DSYNC, we can just use that directly if it
exists (= all targeted systems except DragonFlyBSD), and get rid of our
OPEN_DATASYNC_FLAG macro.

We still avoid choosing open_datasync as a default value for
wal_sync_method if O_DSYNC has the same value as O_SYNC (= only
OpenBSD), so there is no change in default behavior.

Discussion: https://postgr.es/m/CA%2BhUKGJE7y92NY7FG2ftUbZUaqohBU65_Ys_7xF5mUHo4wirTQ%40mail.gmail.com
This commit is contained in:
Thomas Munro
2022-07-22 12:30:37 +12:00
parent 4f1f5a7f85
commit a1b56090eb
3 changed files with 19 additions and 35 deletions

View File

@@ -69,28 +69,12 @@ typedef uint16 RepOriginId;
* are available on the current platform, and to choose an appropriate
* default method. We assume that fsync() is always available, and that
* configure determined whether fdatasync() is.
*
* Note that we define our own O_DSYNC on Windows, but not O_SYNC.
*/
#if defined(O_SYNC)
#define OPEN_SYNC_FLAG O_SYNC
#elif defined(O_FSYNC)
#define OPEN_SYNC_FLAG O_FSYNC
#endif
#if defined(O_DSYNC)
#if defined(OPEN_SYNC_FLAG)
/* O_DSYNC is distinct? */
#if O_DSYNC != OPEN_SYNC_FLAG
#define OPEN_DATASYNC_FLAG O_DSYNC
#endif
#else /* !defined(OPEN_SYNC_FLAG) */
/* Win32 only has O_DSYNC */
#define OPEN_DATASYNC_FLAG O_DSYNC
#endif
#endif
#if defined(PLATFORM_DEFAULT_SYNC_METHOD)
#define DEFAULT_SYNC_METHOD PLATFORM_DEFAULT_SYNC_METHOD
#elif defined(OPEN_DATASYNC_FLAG)
#elif defined(O_DSYNC) && (!defined(O_SYNC) || O_DSYNC != O_SYNC)
#define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN_DSYNC
#elif defined(HAVE_FDATASYNC)
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC