This how to will guide you on installing PostgreSQL 8.1.5 on DirectAdmin
There are two ways to install it:

1). You can install postgresql with yum, however you may not have the latest version installed.

# yum -y install postgresql postgresql-server

2). Alternatively, download the rpms from http://www.postgresql.org/ftp/binary/v8.1.5/linux/rpms/ according to your Operating System distro.
The following are required:

postgresql-libs-8.1.5-3PGDG.i686.rpm
postgresql-8.1.5-3PGDG.i686.rpm
postgresql-server-8.1.5-3PGDG.i686.rpm
postgresql-devel-8.1.5-3PGDG.i686.rpm

(choose rhel-es-4 if your are using CentOS)

Right click on the mirror link and press “T” to copy the url

# wget paste_the_url_here
# wget paste_the_url_here
# wget paste_the_url_here
# wget paste_the_url_here

Install the rpms:

# rpm -ivh postgresql-libs-8.1.5-3PGDG.i686.rpm
# rpm -ivh postgresql-8.1.5-3PGDG.i686.rpm
# rpm -ivh postgresql-server-8.1.5-3PGDG.i686.rpm
# rpm -ivh postgresql-devel-8.1.5-3PGDG.i686.rpm

You have now installed PostgreSQL on your server. The installation is pretty easy. Now we should modify some settings:

# nano -w /var/lib/pgsql/data/pg_hba.conf

If you got these two lines:

host    all         all         127.0.0.1/32          ident sameuser
host    all         all         ::1/128               ident sameuser

Change them to:

host    all         all         127.0.0.1/32          md5
host    all         all         ::1/128               md5

And the following line to the end of the file:
host all all 0.0.0.0 255.255.255.255 reject

so the pg_hba.conf will look like:

local   all         all                               ident sameuser
host    all         all         127.0.0.1/32          md5
host    all         all         ::1/128               md5
host all all 0.0.0.0 255.255.255.255 reject

Start PostgreSQL Server now:

# service postgresql start

Now you need to create a “super user“, like a root account for pgsql that has full privileges.

# su postgres
createuser -P -U postgres da_admin

This command will initiate an user creation script.

Enter password for user ¡§da_admin¡¨:
Enter it again:
Shall the new user be allowed to create databases? (y/n) y
Shall the new user be allowed to create more new users? (y/n) y
CREATE USER
The CREATE USER statement indicates that the command was successful.

Restart postgresql:

# service postgresql restart

We then need to re-compile php with pgsql support.

# cd /usr/local/directadmin/customapache
# nano -w configure.php

add:
--with-pgsql=/var/lib/pgsql \

after:
--with-mysql=/usr \

Save and exit, then type:

# ./build php n

at last restart apache:

#service httpd restart

Now test with the following php code:

<?php
$password="password";
$con=pg_connect("host=localhost dbname=template1 user=da_admin password=$password");
?>

If you dont see any error message, congratualtions you make it