After updating my computer I am unable to do automatic backups of my PostgreSQL 12 database, which has the version:
psql (PostgreSQL) 12.8 (Ubuntu 12.8-Ubuntu0.20.04.1)
Before updating, I was able to run the following code, both manually and using crontab:
pg_dump -h localhost -p 5432 -U brian -d example_db > '/home/brian/.../example_db.bak'
The error I now get is:
pg_dump: error: connection to database "example_db" failed: FATAL: password authentication failed for user "brian"
password retrieved from file "/home/brian/.pgpass"
FATAL: password authentication failed for user "brian"
password retrieved from file "/home/brian/.pgpass"
I have confirmed that my ".pgpass"-file lives up to the manual described here:
PostgreSQL 12 Manual: pgpass
I am also able to log in to my database without being prompted for a password:
brian#pc:~$ psql -U brian -d example_db
Would anyone have an idea why I am unable to use pg_dump when I am able to login to my database without being prompted for my password?
I want to be able to run dropdb mydb. However, when I try to as my normal user I get:
dropdb: error: database removal failed: ERROR: must be owner of database mydb
Now I know that I can just do:
sudo -u postgres dropdb mydb
but that's annoying if I'm trying to script the dropping and re-creation of a DB, because I have to manually enter my sudo password.
I've mostly been able to avoid having to sudo to the postgres user by having a pg_hba.conf with:
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all trust
# IPv4 local connections:
host all all 127.0.0.1/32 trust
# IPv6 local connections:
host all all ::1/128 trust
But for some reason dropdb doesn't seem to respect my pg_hba.conf. Is there some way to make it, so that I can just run dropdb as my regular user?
EDIT: And the same question applies with createdb. I can actually change the DB owner to be able to drop it (thanks stickybit!) ... but then I can't re-create it after.
Unless you're the owner of the database try to pass the -U option with the database owner (or a superuser).
dropdb -U <the database owner> <the database name>
To get the owner of a database you can query the catalog:
SELECT rol.rolname
FROM pg_database dat
LEFT JOIN pg_authid rol
ON rol.oid = dat.datdba
WHERE datname = '<your database name>';
(The above command can be run in psql or any other client, but must be run as the database superuser, e.g. postgres on most UNIX-based systems.)
To be able to create databases (with createdb or other means), you need to grant yourself the privilege to create databases.
ALTER USER <your user name> CREATEDB;
(Again, that can be run in psql or any other client, but must be run as database super user, e.g. postgres.)
You then should be the owner of the database automatically unless you specify otherwise and can therefore drop it again.
Of course you can also grant yourself superuser privileges analogously.
ALTER USER <your user name> SUPERUSER;
I want to connect to my postgresql when running my python program. The issue i face is that my username is dave, but i can only access my database with the user postgres on linux. This constellation never failed me on my mac, because i could start postgres from my "dave" user account. With linux (ubuntu) i can only connect to the database with psql, when switching my user with *sudo -su postgres to the postgres user.
How am i able to start my program from my user dave while accessing the database?
You'll have to create a user called dave:
Log on using sudo -u postgres
create database davedb;
create user dave with encrypted password 'testing';
grant all privileges on database davedb to dave;
Then, you can log in from your username itself like so:
psql dave davedb
--or--
psql -U dave -d davedb
If it asks you for your password, type it. You should be in then.
So I set up a user called 'paperwork' with a database of the same name
postgres=# create role paperwork;
postgres=# create database paperwork;
postgres=# grant all privileges on database paperwork to paperwork;
postgres=# ALTER ROLE paperwork WITH LOGIN;
postgres=# ALTER ROLE paperwork WITH PASSWORD 'paperwork';
But it still lets me log in as paperwork without a password
[####EMOO modules]$ psql --username=paperwork --host=localhost
psql (9.6.3)
Type "help" for help.
paperwork=> \q
and when I force it to use a password, it accepts any password including blank password:
[####EMOO modules]$ psql --username=paperwork --host=localhost --password
Password for user paperwork:
psql (9.6.3)
Type "help" for help.
When I open up pgadmin3 and click on the "paperwork" user it seems to have an encrypted password.
-- Role: paperwork
-- DROP ROLE paperwork;
CREATE ROLE paperwork LOGIN
ENCRYPTED PASSWORD 'md585ff97314dbeb9953b989fd363a8e96f'
NOSUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION;
Also, when I open up pgadmin3 it asks me for the postgres password, but again will accept anything for the postgres password. (and I remember setting the postgres password when I installed postgres) How do I make it so you need the right password to login? Or is there some context here that I am missing entirely? . . . like passwords are only needed for remote logins or some weirdness. Thanks.
EDIT: I didn't have a /usr/share/postgresql/pg_hba.conf (EDIT: actually I did I just couldn't find it because I wasn't using sudo on the "locate" command)
I created one from the sample file: /usr/share/postgresql/pg_hba.conf.sample
Got this idea from here: http://blog.mattsch.com/2012/05/19/postgresql-accepts-any-or-no-password-when-connecting/
I tried making it have md5 authentication but I still have the same problem. What I tried is below from the file /usr/share/postgresql/pg_hba.conf
#authcomment#
# TYPE DATABASE USER ADDRESS METHOD
#remove-line-for-nolocal## "local" is for Unix domain socket connections only
#remove-line-for-nolocal#local all all #authmethodlocal#
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5
# Allow replication connections from localhost, by a user with the
# replication privilege.
#remove-line-for-nolocal##local replication #default_username# #authmethodlocal#
#host replication #default_username# 127.0.0.1/32 #authmethodhost#
#host replication #default_username# ::1/128 #authmethodhost#
I then restarted postgresql but still have the same problem.
EDIT: Thanks Abelisto. that "show config_file" command (after logging in with pgsql) put me on the right track. It didn't occure to me that "locate pg_hba.conf" run from my linux user's command line didn't have permission to find the actual config file in the postgres directory: /var/lib/postgres/data/ The user "paperwork" now gets rejected with the wrong password after I changed "trust" to "md5" in /var/lib/postgres/data/pg_hba.conf on these lines to make it:
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all md5
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5
Will probably mark solved in a bit just want to test a couple things.
TLDR for my original post:
Make sure you have set the postgres password to something you know:
[####EMOO ~]$ psql -U postgres
psql (9.6.3)
Type "help" for help.
postgres=# ALTER ROLE postgres WITH PASSWORD 'postgres password';
Find your pg_hba.conf:
sudo updatedb
sudo locate pg_hba.conf
Replace "trust" with "md5" in your pg_hba.conf:
Restart PostgreSQL:
sudo systemctl restart postgresql
Log in as postgres and change whatever user passwords you need. Users will now be rejected if they don't provide the right password.
psql -U postgres
I have just installed postgresql and I specified password x during installation.
When I try to do createdb and specify any password I get the message:
createdb: could not connect to database postgres: FATAL: password authentication failed for user
Same for createuser.
How should I start?
Can I add myself as a user to the database?
The other answers were not completely satisfying to me. Here's what worked for postgresql-9.1 on Xubuntu 12.04.1 LTS.
Connect to the default database with user postgres:
sudo -u postgres psql template1
Set the password for user postgres, then exit psql (Ctrl-D):
ALTER USER postgres with encrypted password 'xxxxxxx';
Edit the pg_hba.conf file:
sudo vim /etc/postgresql/9.1/main/pg_hba.conf
and change "peer" to "md5" on the line concerning postgres:
local all postgres peer md5
To know what version of postgresql you are running, look for the version folder under /etc/postgresql. Also, you can use Nano or other editor instead of VIM.
Restart the database :
sudo /etc/init.d/postgresql restart
(Here you can check if it worked with psql -U postgres).
Create a user having the same name as you (to find it, you can type whoami):
sudo createuser -U postgres -d -e -E -l -P -r -s <my_name>
The options tell postgresql to create a user that can login, create databases, create new roles, is a superuser, and will have an encrypted password. The really important ones are -P -E, so that you're asked to type the password that will be encrypted, and -d so that you can do a createdb.
Beware of passwords: it will first ask you twice the new password (for the new user), repeated, and then once the postgres password (the one specified on step 2).
Again, edit the pg_hba.conf file (see step 3 above), and change "peer" to "md5" on the line concerning "all" other users:
local all all peer md5
Restart (like in step 4), and check that you can login without -U postgres:
psql template1
Note that if you do a mere psql, it will fail since it will try to connect you to a default database having the same name as you (i.e. whoami). template1 is the admin database that is here from the start.
Now createdb <dbname> should work.
Under Linux PostgresQL is usually configured to allow the root user to login as the postgres superuser postgres from the shell (console or ssh).
$ psql -U postgres
Then you would just create a new database as usual:
CREATE ROLE myuser LOGIN password 'secret';
CREATE DATABASE mydatabase ENCODING 'UTF8' OWNER myuser;
This should work without touching pg_hba.conf. If you want to be able to do this using some GUI tool over the network - then you would need to mess with pg_hba.conf.
There are two methods you can use. Both require creating a user and a database.
Using createuser and createdb,
$ sudo -u postgres createuser --superuser $USER
$ createdb mydatabase
$ psql -d mydatabase
Using the SQL administration commands, and connecting with a password over TCP
$ sudo -u postgres psql postgres
And, then in the psql shell
CREATE ROLE myuser LOGIN PASSWORD 'mypass';
CREATE DATABASE mydatabase WITH OWNER = myuser;
Then you can login,
$ psql -h localhost -d mydatabase -U myuser -p <port>
If you don't know the port, you can always get it by running the following, as the postgres user,
SHOW port;
Or,
$ grep "port =" /etc/postgresql/*/main/postgresql.conf
Sidenote: the postgres user
I suggest NOT modifying the postgres user.
It's normally locked from the OS. No one is supposed to "log in" to the operating system as postgres. You're supposed to have root to get to authenticate as postgres.
It's normally not password protected and delegates to the host operating system. This is a good thing. This normally means in order to log in as postgres which is the PostgreSQL equivalent of SQL Server's SA, you have to have write-access to the underlying data files. And, that means that you could normally wreck havoc anyway.
By keeping this disabled, you remove the risk of a brute force attack through a named super-user. Concealing and obscuring the name of the superuser has advantages.
This is my solution:
su root
su postgres
psql
EDIT: Warning: Please, read the answer posted by Evan Carroll. It seems that this solution is not safe and not recommended.
This worked for me in the standard Ubuntu 14.04 64 bits installation.
I followed the instructions, with small modifications, that I found in http://suite.opengeo.org/4.1/dataadmin/pgGettingStarted/firstconnect.html
Install postgreSQL (if not already in your machine):
sudo apt-get install postgresql
Run psql using the postgres user
sudo –u postgres psql postgres
Set a new password for the postgres user:
\password postgres
Exit psql
\q
Edit /etc/postgresql/9.3/main/pg_hba.conf and change:
#Database administrative login by Unix domain socket
local all postgres peer
To:
#Database administrative login by Unix domain socket
local all postgres md5
Restart postgreSQL:
sudo service postgresql restart
Create a new database
sudo –u postgres createdb mytestdb
Run psql with the postgres user again:
psql –U postgres –W
List the existing databases (your new database should be there now):
\l
In MacOS, I followed the below steps to make it work.
For the first time, after installation, get the username of the system.
$ cd ~
$ pwd
/Users/someuser
$ psql -d postgres -U someuser
Now that you have logged into the system, and you can create the DB.
postgres=# create database mydb;
CREATE DATABASE
postgres=# create user myuser with encrypted password 'pass123';
CREATE ROLE
postgres=# grant all privileges on database mydb to myuser;
GRANT
If you're running macOS like I am, you may not have the postgres user.
When trying to run sudo -u postgres psql I was getting the error sudo: unknown user: postgres
Luckily there are executables that postgres provides.
createuser -D /var/postgres/var-10-local --superuser --username=nick
createdb --owner=nick
Then I was able to access psql without issues.
psql
psql (10.2)
Type "help" for help.
nick=#
If you're creating a new postgres instance from scratch, here are the steps I took. I used a non-default port so I could run two instances.
mkdir /var/postgres/var-10-local
pg_ctl init -D /var/postgres/var-10-local
Then I edited /var/postgres/var-10-local/postgresql.conf with my preferred port, 5433.
/Applications/Postgres.app/Contents/Versions/10/bin/postgres -D /Users/nick/Library/Application\ Support/Postgres/var-10-local -p 5433
createuser -D /var/postgres/var-10-local --superuser --username=nick --port=5433
createdb --owner=nick --port=5433
Done!
Note: textdb is the database which you are going to explore with 'alex' user
root#kalilinux:~# sudo su - postgres
postgres=# psql
postgres=# create database testdb;
postgres=# create user alex with password 'alex';
postgres=# GRANT ALL PRIVILEGES ON DATABASE testdb TO alex;`enter code here`
You probably need to update your pg_hba.conf file. This file controls what users can log in from what IP addresses. I think that the postgres user is pretty locked-down by default.
Just browse up to your installation's directory and execute this file "pg_env.bat", so after go at bin folder and execute pgAdmin.exe. This must work no doubt!