Thank you for your reply.
I agree, However we are planning, users not to have any direct privileges on database objects or default roles(like SUPERUSER,CREATEDB,REPLICATION..etc) in postgres.
looking to create users(LOGIN) only and Grant all the privileges through roles like below.
Steps:
Create User
Create role
GRANT required privileges/default attributes(SUPERUSER,REPLICATION etc) to Role
GRANT role to Users.
So,If I follow above process I am not able to do pg_basebackup.
Now I have only options left either I have to use postgres user or create a user directly with replication role(Which we are not interested in).
In future is there possibility to allow a user(using above steps) to do pg_basebackup?.
Thanks,
Chiru