Обсуждение: pgsql: pg_start_backup() can use a share lock to lock ControlFileLock

Log Message:
-----------
pg_start_backup() can use a share lock to lock ControlFileLock
instead of an exclusive lock.

The change is almost for code cleanup. Since there seems to be no
performance benefits from it, backports should not be needed.

Fujii Masao

Modified Files:
--------------
    pgsql/src/backend/access/transam:
        xlog.c (r1.379 -> r1.380)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c?r1=1.379&r2=1.380)