Changing DCNM Postgres Database Password

If the customer cannot recall their Postgres database password, which is usually a problem during a re-install of DCNM where the Postgres database already exists, they will need to reset it.

This solution is for Windows environments only.

The user has forgotten their PostgreSQL database password and has no record of it / way of getting it.

If you cannot recall a server's Postgres database password (Cisco DCNM's database), follow this process: 
Since you've lost/forgotten it you'll have to reset it.
(There is no recovery method which allows you to find out what it's currently set to.)

Begin:
Find your pg_hba.conf file, usually in C:\Program Files\PostgreSQL\9.1\data\pg_hba.conf

If necessary, set permissions on it so you can modify it; your user account might not be able to do so until you use the Security tab in the Properties dialog (to give yourself that right by using an admin override).
Alternately, you can instead find a text editor of your choice, such as Notepad / Notepad++, right click it, choose "Run as administrator", then use File > Open to open the pg_hba.conf file that way.

Edit the file to set the "host" line for user "username" on host "127.x.x.1/32" to "trust".
You can add the "host" line if it isn't there; just insert:
     host  all  username  127.x.x.1/32  trust
... before any other user lines. (You can ignore comments; which are the lines beginning with #'s).

Then, restart the PostgreSQL service from the (Windows) Services control panel (start > run > services.msc).

You can then either:
Set a new password for that username in the DCNM installation process...
- OR -
Start up PgAdmin-III to connect to the dcnm postgres database, and choose ALTER USER username PASSWORD 'postgres', to remove the line you added to pg_hba.conf, or change it to the password you want.