Log Message:
-----------
Document that wal_sync_method open_* methods use O_DIRECT, if available.
Backpatch to 8.2.X.
Modified Files:
--------------
pgsql/doc/src/sgml:
config.sgml (r1.108 -> r1.109)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.108&r2=1.109)