Обсуждение: pgsql: Remove the special variable for open_sync_bit used in O_SYNC and

Log Message:
-----------
Remove the special variable for open_sync_bit used in O_SYNC and O_DSYNC
modes, replacing it with a call to a function that derives it from the
sync_method variable, now that it has distinct values for these two cases.

This means that assign_xlog_sync_method() no longer changes any settings,
thus fixing the bug introduced in the change to use a guc enum for
wal_sync_method.

Modified Files:
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    pgsql/src/backend/access/transam:
        xlog.c (r1.308 -> r1.309)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c?r1=1.308&r2=1.309)