postgresql - I forgot the password I entered during postgres installation

Question

I either forgot or mistyped (during the installation) the password to the default user of Postgres. I can't seem to be able to run it and I get the following error:

psql: FATAL:  password authentication failed for user "hisham"
hisham-agil: hisham$ psql 

Is there anyway to reset the password or how do I create a new user with superuser privileges?

I am new to Postgres and just installed it for the first time. I am trying to use it with Rails and I am running Mac OS X Lion.

Answer 1

1. find the file pg_hba.conf - it may be located, for example in /etc/postgresql-9.1/pg_hba.conf.

   cd /etc/postgresql-9.1/

2. Back it up

   cp pg_hba.conf pg_hba.conf-backup

3. place the following line (as either the first uncommented line, or as the only one):

For all occurrence of below (local and host) , exepct replication section if you don't have any it has to be changed as follow ,no MD5 or Peer autehication should be present.

local  all   all   trust

4. restart your PostgreSQL server (e.g., on Linux:)

   sudo /etc/init.d/postgresql restart

   If the service (daemon) doesn't start reporting in log file:

   local connections are not supported by this build

   you should change

   local all all trust

   to

   host all all 127.0.0.1/32 trust

5. you can now connect as any user. Connect as the superuser postgres (note, the superuser name may be different in your installation. In some systems it is called pgsql, for example.)

   psql -U postgres

   or

   psql -h 127.0.0.1 -U postgres

   (note that with the first command you will not always be connected with local host)

6. Reset password ('replace my_user_name with postgres since you are resetting postgres user)

   ALTER USER my_user_name with password 'my_secure_password';

7. Restore the old pg_hba.conf as it is very dangerous to keep around

   cp pg_hba.conf-backup pg_hba.conf

8. restart the server, in order to run with the safe pg_hba.conf

   sudo /etc/init.d/postgresql restart

Further Reading about that pg_hba file: http://www.postgresql.org/docs/9.1/static/auth-pg-hba-conf.html