Function test_sync

src/bin/pg_test_fsync/pg_test_fsync.c:261–425

}

static void
test_sync(int writes_per_op)
{
	int			tmpfile,
				ops,
				writes;
	bool		fs_warning = false;

	if (writes_per_op == 1)
		printf(_("\nCompare file sync methods using one %dkB write:\n"), XLOG_BLCKSZ_K);
	else
		printf(_("\nCompare file sync methods using two %dkB writes:\n"), XLOG_BLCKSZ_K);
	printf(_("(in wal_sync_method preference order, except fdatasync is Linux's default)\n"));

	/*
	 * Test open_datasync if available
	 */
	printf(LABEL_FORMAT, "open_datasync");
	fflush(stdout);

#ifdef OPEN_DATASYNC_FLAG
	if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT | PG_BINARY, 0)) == -1)
	{
		printf(NA_FORMAT, _("n/a*"));
		fs_warning = true;
	}
	else
	{
		START_TIMER;
		for (ops = 0; alarm_triggered == false; ops++)
		{
			for (writes = 0; writes < writes_per_op; writes++)
				if (pg_pwrite(tmpfile,
							  buf,
							  XLOG_BLCKSZ,
							  writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
					die("write failed");
		}
		STOP_TIMER;
		close(tmpfile);
	}
#else
	printf(NA_FORMAT, _("n/a"));
#endif

/*
 * Test fdatasync if available
 */
	printf(LABEL_FORMAT, "fdatasync");
	fflush(stdout);

#ifdef HAVE_FDATASYNC
	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++)
	{
		for (writes = 0; writes < writes_per_op; writes++)