[postgresql] How to thoroughly purge and reinstall postgresql on ubuntu?

Somehow I've managed to completely bugger the install of postgresql on Ubuntu karmic. I want to start over from scratch, but when I "purge" the package with apt-get it still leaves traces behind such that the reinstall configuration doesn't run properly.

After I've done:

apt-get purge postgresql
apt-get install postgresql

It said

Setting up postgresql-8.4 (8.4.3-0ubuntu9.10.1) ...
Configuring already existing cluster (configuration: /etc/postgresql/8.4/main, data: /var/lib/postgresql/8.4/main, owner: 108:112)
Error: move_conffile: required configuration file     /var/lib/postgresql/8.4/main/postgresql.conf does not exist
Error: could not create default cluster. Please create it manually with

  pg_createcluster 8.4 main --start

or a similar command (see 'man pg_createcluster').
update-alternatives: using /usr/share/postgresql/8.4/man/man1/postmaster.1.gz to provide /usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode.

Setting up postgresql (8.4.3-0ubuntu9.10.1) ...

I have a "/etc/postgresql" with nothing in it and "/etc/postgresql-common/" has a 'pg_upgradecluser.d' directory and root.crt and user_clusters files.

The /etc/passwd has a postgres user; the purge script doesn't appear to touch it. There's been a bunch of symptoms which I work through only to expose the next.

Right this second, when I run that command "pg_createcluster..." it complains that '/var/lib/postgresql/8.4/main/postgresql.conf does not exist', so I'll go find one of those but I'm sure that won't be the end of it.

Is there not some easy one-liner (or two) which will burn it completely and let me start over?

I was following the replies, When editing /etc/group I also deleted this line:

ssl-cert:x:112:postgres

then, when trying to install postgresql, I got this error

Preconfiguring packages ...
dpkg: unrecoverable fatal error, aborting:
 syntax error: unknown group 'ssl-cert' in statoverride file
E: Sub-process /usr/bin/dpkg returned an error code (2)

Putting the "ssl-cert:x:112:postgres" line back in /etc/group seems to fix it (so I was able to install postgresql)

apt-get purge postgresql*

is enough.

I know an answer has already been provided, but dselect didn't work for me. Here is what worked to find the packages to remove:

# search postgr  | grep ^i
i   postgresql                      - object-relational SQL database (supported 
i A postgresql-8.4                  - object-relational SQL database, version 8.
i A postgresql-client-8.4           - front-end programs for PostgreSQL 8.4     
i A postgresql-client-common        - manager for multiple PostgreSQL client ver
i A postgresql-common               - PostgreSQL database-cluster manager       

# aptitude purge postgresql-8.4 postgresql-client-8.4 postgresql-client-common postgresql-common postgresql

rm -r /etc/postgresql/
rm -r /etc/postgresql-common/
rm -r /var/lib/postgresql/

Finally, editing /etc/passwd and /etc/group

Following ae the steps i followed to uninstall and reinstall. Which worked for me.

First remove the installed postgres :-

sudo apt-get purge postgr*

sudo apt-get autoremove

Then install 'synaptic':

sudo apt-get install synaptic

sudo apt-get update

Then install postgres

sudo apt-get install postgresql postgresql-contrib

Steps that worked for me on Ubuntu 8.04.2 to remove postgres 8.3

1. List All Postgres related packages

   dpkg -l | grep postgres
   
   ii  postgresql                            8.3.17-0ubuntu0.8.04.1           object-relational SQL database (latest versi
   ii  postgresql-8.3                        8.3.9-0ubuntu8.04                object-relational SQL database, version 8.3
   ii  postgresql-client                     8.3.9-0ubuntu8.04                front-end programs for PostgreSQL (latest ve
   ii  postgresql-client-8.3                 8.3.9-0ubuntu8.04                front-end programs for PostgreSQL 8.3
   ii  postgresql-client-common              87ubuntu2                        manager for multiple PostgreSQL client versi
   ii  postgresql-common                     87ubuntu2                        PostgreSQL database-cluster manager
   ii  postgresql-contrib                    8.3.9-0ubuntu8.04                additional facilities for PostgreSQL (latest
   ii  postgresql-contrib-8.3                8.3.9-0ubuntu8.04                additional facilities for PostgreSQL
   

2. Remove all above listed

   sudo apt-get --purge remove postgresql postgresql-8.3  postgresql-client  postgresql-client-8.3 postgresql-client-common postgresql-common  postgresql-contrib postgresql-contrib-8.3
   

3. Remove the following folders

   sudo rm -rf /var/lib/postgresql/
   sudo rm -rf /var/log/postgresql/
   sudo rm -rf /etc/postgresql/
   

I was facing same problem in my ubuntu 16.04

but i fixed that problem and it's very simple just follow these step and you will be able to install postgresql 10 in your system :

Add this to your sources.list:

sudo vim /etc/apt/sources.list

deb http://ftp.de.debian.org/debian/ wheezy main non-free contrib

deb-src http://ftp.de.debian.org/debian/ wheezy main non-free contrib

after that add these link to your pgdg.list file if it's not there you have to create && add link && save it.

sudo vim /etc/apt/sources.list.d/pgdg.list

deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main

deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main

then update your system

sudo apt-get update

sudo apt-get upgrade

and install that unmet dependencies :

apt-get install ssl-cert

that's it. now Install postgresql using these command

sudo apt-get install postgresql-10

I just ran into the same issue for Ubuntu 13.04. These commands removed Postgres 9.1:

sudo apt-get purge postgresql
sudo apt-get autoremove postgresql

It occurs to me that perhaps only the second command is necessary, but from there I was able to install Postgres 9.2 (sudo apt-get install postgresql-9.2).

I had a similar situation: I needed to purge postgresql 9.1 on a debian wheezy ( I had previously migrated from 8.4 and I was getting errors ).

What I did:

First, I deleted config and database

$ sudo pg_dropcluster --stop 9.1 main

Then removed postgresql

$ sudo apt-get remove --purge postgresql postgresql-9.1 

and then reinstalled

$ sudo apt-get install postgresql postgresql-9.1

In my case I noticed /etc/postgresql/9.1 was empty, and running service postgresql start returned nothing

So, after more googling I got to this command:

$ sudo pg_createcluster 9.1 main

With that I could start the server, but now I was getting log-related errors. After more searching, I ended up changing permissions to the /var/log/postgresql directory

$ sudo chown root.postgres /var/log/postgresql
$ sudo chmod g+wx /var/log/postgresql

That fixed the issue, Hope this helps