"Vilson farias" <vilson.farias@digitro.com.br> writes:
> I have a pg_pwd too with this text inside :
> [postgres@bxsgalena data]$ cat pg_pwd
> postgres 0 x x x x 1 \N
> What is it used for?
pg_pwd is a plain-ASCII dump of the pg_shadow table. It's used by the
postmaster (since the postmaster can't read database tables by itself).
AFAIR it's only used if you specify password auth based on the pg_shadow
password.
However, you need to have pg_shadow entries for all your PG users
regardless of what your connection authorization setup may be.
relowner and so forth are supposed to be references to pg_shadow rows.
regards, tom lane