Install PostgreSQL 9 on CentOS

This post will cover installing and basic configuration of PostgreSQL 9.x on CentOS.

We will install PostgreSQL 9 using the PostgreSQL repository and yum.

The same procedure can be used to install PostgreSQL 9 on Red Hat and Fedora using the appropriate rpm.

Optionally, we'll also see how to install PostGIS.

As the directory structure of PostgreSQL has changed with the release of PostgreSQL 9, we will also look a look at how we can create symlinks to make life easier when installing software or modules that still expect the old directory structure.

Finally, for Webmin users, we will see how to configuring Webmin to manage PostgreSQL 9.

I am using CentOS 6, but the same procedure works for CentOS 5. Finally, if you are using Webmin, we will also show how to configure Webmin to manage PostgreSQL 9.

With the release of PostgreSQL 9, the directory structure of PostgreSQL has changed.

We will also creating symlinks (if needed) from the new PostgreSQL 9 file locations to the previous PostgreSQL 8 file locations.

If you are looking trying to install PostgreSQL 9 on cPanel, please see my post here.

We'll use the simplest method to install, which is the postrgres repo rpms.





Download the latest production release for your distro here: http://yum.pgrpms.org/repopackages.php

The repo rpms are 32 and 64 bit specific.

Since I am installing on CentOS 6 x64, I will need:

http://yum.pgrpms.org/9.1/redhat/rhel-5-x86_64/pgdg-centos91-9.1-4.noarch.rpm

So, using wget:

wget http://yum.pgrpms.org/9.1/redhat/rhel-6-x86_64/pgdg-centos91-9.1-4.noarch.rpm

[root@server1 ~]# wget http://yum.pgrpms.org/9.1/redhat/rhel-6-x86_64/pgdg-centos91-9.1-4.noarch.rpm
--2011-11-01 00:11:50--  http://yum.pgrpms.org/9.1/redhat/rhel-6-x86_64/pgdg-centos91-9.1-4.noarch.rpm
Resolving yum.pgrpms.org... 98.129.198.114
Connecting to yum.pgrpms.org|98.129.198.114|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 5124 (5.0K) [application/x-redhat-package-manager]
Saving to: pgdg-centos91-9.1-4.noarch.rpm

100%[======================================>] 5,124       --.-K/s   in 0s

2011-11-01 00:11:51 (310 MB/s) - pgdg-centos91-9.1-4.noarch.rpm

[root@server1 ~]# 

Now, install the repo....

[root@server1 ~]# rpm -i pgdg-centos91-9.1-4.noarch.rpm

We now need to edit the CentOS-Base.repo to exclude postgreql.

To do, so we simply edit CentOS-Base.repo and add 'exclude=postgresql*' to the [base] and [updates] sections:

[root@server1 ~]# cd /etc/yum.repos.d
[root@server1 yum.repos.d]# vi CentOS-Base.repo

[root@server1 yum.repos.d]# vi CentOS-Base.repo
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
exclude=postgresql*

#released updates
[updates]
name=CentOS-$releasever - Updates
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
exclude=postgresql*

Now, let's use 'yum list' to check the packages that are now available.

[root@server1 yum.repos.d]# yum list postgres*
Loaded plugins: fastestmirror
base                                                     | 3.7 kB     00:00
base/primary_db                                          | 4.2 MB     00:09
extras                                                   | 3.0 kB     00:00
extras/primary_db                                        | 1.9 kB     00:00
pgdg91                                                   | 2.8 kB     00:00
pgdg91/primary_db                                        |  79 kB     00:00
updates                                                  | 3.5 kB     00:00
updates/primary_db                                       | 3.3 MB     00:00
vz-base                                                  |  951 B     00:00
vz-base/primary                                          | 1.3 kB     00:00
vz-base                                                                     3/3
vz-updates                                               |  951 B     00:00
vz-updates/primary                                       |  157 B     00:00
Available Packages
postgresql91.x86_64                         9.1.1-1PGDG.rhel6             pgdg91
postgresql91-contrib.x86_64                 9.1.1-1PGDG.rhel6             pgdg91
postgresql91-debuginfo.x86_64               9.1.1-1PGDG.rhel6             pgdg91
postgresql91-devel.i686                     9.1.1-1PGDG.rhel6             pgdg91
postgresql91-devel.x86_64                   9.1.1-1PGDG.rhel6             pgdg91
postgresql91-docs.x86_64                    9.1.1-1PGDG.rhel6             pgdg91
postgresql91-jdbc.x86_64                    9.1.901-1PGDG.rhel6           pgdg91
postgresql91-jdbc-debuginfo.x86_64          9.1.901-1PGDG.rhel6           pgdg91
postgresql91-libs.i686                      9.1.1-1PGDG.rhel6             pgdg91
postgresql91-libs.x86_64                    9.1.1-1PGDG.rhel6             pgdg91
postgresql91-odbc.x86_64                    09.00.0200-1PGDG.rhel6        pgdg91
postgresql91-odbc-debuginfo.x86_64          09.00.0200-1PGDG.rhel6        pgdg91
postgresql91-plperl.x86_64                  9.1.1-1PGDG.rhel6             pgdg91
postgresql91-plpython.x86_64                9.1.1-1PGDG.rhel6             pgdg91
postgresql91-pltcl.x86_64                   9.1.1-1PGDG.rhel6             pgdg91
postgresql91-python.x86_64                  4.0-2PGDG.rhel6               pgdg91
postgresql91-python-debuginfo.x86_64        4.0-2PGDG.rhel6               pgdg91
postgresql91-server.x86_64                  9.1.1-1PGDG.rhel6             pgdg91
postgresql91-tcl.x86_64                     1.9.0-1.rhel6                 pgdg91
postgresql91-tcl-debuginfo.x86_64           1.9.0-1.rhel6                 pgdg91
postgresql91-test.x86_64                    9.1.1-1PGDG.rhel6             pgdg91
postgresql_autodoc.noarch                   1.40-1.rhel6                  pgdg91
[root@server1 yum.repos.d]#

We can now install PostgreSQL 9 using yum:

yum install postgresql91 postgresql91-devel postgresql91-server postgresql91-libs postgresql91-contrib

[root@server1 yum.repos.d]# yum install postgresql91 postgresql91-devel postgresql91-server postgresql91-libs postgresql91-contrib
Loaded plugins: fastestmirror
Determining fastest mirrors
 * base: mirror.us.leaseweb.net
 * extras: mirror.lug.udel.edu
 * updates: centos.mirror.choopa.net
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package postgresql91.x86_64 0:9.1.1-1PGDG.rhel6 set to be updated
---> Package postgresql91-devel.x86_64 0:9.1.1-1PGDG.rhel6 set to be updated
---> Package postgresql91-libs.x86_64 0:9.1.1-1PGDG.rhel6 set to be updated
---> Package postgresql91-server.x86_64 0:9.1.1-1PGDG.rhel6 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package                  Arch        Version                 Repository   Size
================================================================================
Installing:
 postgresql91             x86_64      9.1.1-1PGDG.rhel6       pgdg91      939 k
 postgresql91-devel       x86_64      9.1.1-1PGDG.rhel6       pgdg91      1.4 M
 postgresql91-libs        x86_64      9.1.1-1PGDG.rhel6       pgdg91      186 k
 postgresql91-server      x86_64      9.1.1-1PGDG.rhel6       pgdg91      3.4 M

Transaction Summary
================================================================================
Install       4 Package(s)
Upgrade       0 Package(s)

Total download size: 5.9 M
Installed size: 25 M
Is this ok [y/N]: y
Downloading Packages:
(1/4): postgresql91-9.1.1-1PGDG.rhel6.x86_64.rpm         | 939 kB     00:02
(2/4): postgresql91-devel-9.1.1-1PGDG.rhel6.x86_64.rpm   | 1.4 MB     00:01
(3/4): postgresql91-libs-9.1.1-1PGDG.rhel6.x86_64.rpm    | 186 kB     00:00
(4/4): postgresql91-server-9.1.1-1PGDG.rhel6.x86_64.rpm  | 3.4 MB     00:02
--------------------------------------------------------------------------------
Total                                           800 kB/s | 5.9 MB     00:07
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : postgresql91-libs-9.1.1-1PGDG.rhel6.x86_64               1/4
  Installing     : postgresql91-9.1.1-1PGDG.rhel6.x86_64                    2/4
  Installing     : postgresql91-server-9.1.1-1PGDG.rhel6.x86_64             3/4
  Installing     : postgresql91-devel-9.1.1-1PGDG.rhel6.x86_64              4/4

Installed:
  postgresql91.x86_64 0:9.1.1-1PGDG.rhel6
  postgresql91-devel.x86_64 0:9.1.1-1PGDG.rhel6
  postgresql91-libs.x86_64 0:9.1.1-1PGDG.rhel6
  postgresql91-server.x86_64 0:9.1.1-1PGDG.rhel6

Complete!
[root@server1 yum.repos.d]#

We can now initialize and Start PostgreSQL

NOTE: when using Webmin, please see 'Configuring Webmin to Manage PostgreSQL9 below:

[root@server1 yum.repos.d]# service postgresql-9.1 initdb
Initializing database:                                     [  OK  ]
[root@server1 yum.repos.d]#

Start the PostgreSQL server:

[root@server1 yum.repos.d]# service postgresql-9.1 start
Starting postgresql-9.1 service:                           [  OK  ]
[root@server1 yum.repos.d]#

If you encounter startup errors, check under /var/lib/pgsql/9.1/data/pg_log for clues.





The deault home directory for the user postgres is at /var/lib/pgsql

The bash_profile for the user postgres will look like this:

[ -f /etc/profile ] && source /etc/profile
PGDATA=/var/lib/pgsql/9.1/data
export PGDATA

This contains a path for the data directory, but no path for the executable/binary directory. To ammend this, add the path as below:

[ -f /etc/profile ] && source /etc/profile
PGDATA=/var/lib/pgsql/9.1/data
export PGDATA
PATH=$PATH:$HOME/bin:/usr/pgsql-9.1/bin
export PATH

Placing the binary directory in the path for postgres will allow you to invoke pg_ctl and other commands from the shell.





The superuser postgres has no password set by default.

To set the password, switch to postgres user:

[root@server1 yum.repos.d]# su - postgres

Connect as postgres to the postgres database and set the password for user postgres using alter user as below:

-bash-4.1$ psql postgres postgres
psql (9.1.1)
Type "help" for help.

postgres=# alter user postgres with password 'postgres';
ALTER ROLE
postgres=#

Locate your pg_hba.conf file under /var/lib/pgsql/9.1/data

On installation, your pg_hba.conf file will look like this:

[root@server1 yum.repos.d]# vi /var/lib/pgsql/9.1/data/pg_hba.conf
# Put your actual configuration here
# ----------------------------------
#
# If you want to allow non-local connections, you need to add more
# "host" records.  In that case you will also need to make PostgreSQL
# listen on a non-local interface via the listen_addresses
# configuration parameter, or via the -i or -h command line switches.



# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     peer
# IPv4 local connections:
host    all             all             127.0.0.1/32            ident
# IPv6 local connections:
host    all             all             ::1/128                 ident
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local   replication     postgres                                peer
#host    replication     postgres        127.0.0.1/32            ident
#host    replication     postgres        ::1/128                 ident

Change the METHOD to md5 as shown below:

# 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

In order for the change to take effect, reload the pg_hba.conf file.

As with any command, there are several ways you can reload the pg_hba.conf file.

Method 1: From the shell using pg_ctl reload:

[root@server1 yum.repos.d]# su - postgres
-bash-4.1$ pg_ctl reload
server signaled
-bash-4.1$

Method 2: From psql using pg_reload_conf();

-bash-4.1$ psql postgres postgres
psql (9.1.1)
Type "help" for help.

postgres=# select pg_reload_conf();
 pg_reload_conf
----------------
 t
(1 row)

postgres=#

Method 3: From the shell using -c switch to run select pg_reload_conf();

-bash-4.1$ psql postgres postgres -c "select pg_reload_conf();"
Password for user postgres:
 pg_reload_conf
----------------
 t
(1 row)

-bash-4.1$

Locate the postgresql.conf file under /var/lib/pgsql/9.1/data.

Look for CONNECTIONS AND AUTHENTICATION. It will look as below:

#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------

# - Connection Settings -

#listen_addresses = 'localhost'		# what IP address(es) to listen on;
					# comma-separated list of addresses;
					# defaults to 'localhost', '*' = all
					# (change requires restart)
#port = 5432				# (change requires restart)

By default, access is limited to local machine (localhost).

To enable remote connections, uncomment listen_addresses and change to '*' as shown below.

#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------

# - Connection Settings -

listen_addresses = '*'		# what IP address(es) to listen on;
					# comma-separated list of addresses;
					# defaults to 'localhost', '*' = all
					# (change requires restart)
#port = 5432				# (change requires restart)

You can also set the listen_address limit to a specific IP (or IPs using a comma separated list).

Note: For security, it is also a good idea to change the default port. To do this, uncomment port and set to a new port value.

If you change the port, you will need to restart the service.

Restart the postgresql service:

service postgresql-9.1 restart
Stopping postgresql-9.1 service:                           [  OK  ]
Starting postgresql-9.1 service:                           [  OK  ]
[root@server1 yum.repos.d]#

If you encounter startup errors, check under /var/lib/pgsql/9.1/data/pg_log for clues.

Verify the changes to listen_address and port (if changed):

-bash-4.1$ psql
Password:
psql (9.1.1)
Type "help" for help.

postgres=# show listen_addresses;
 listen_addresses
------------------
 *
(1 row)


postgres=# show port;
 port
------
 5432
(1 row)

postgres=#

To check Check functionality, connect to postgres db as user postgres.

[root@server1 yum.repos.d]# psql postgres postgres
Password for user postgres:
psql (9.1.1)
Type "help" for help.

postgres=#

Create a user:

postgres=# create user myuser with password 'secret';
CREATE ROLE

Create a database and give ownership to the new user:

postgres=# create database mytestdb owner=myuser;
CREATE DATABASE

Connect to the database as user:

postgres=# \c mytestdb myuser
Password for user myuser:
You are now connected to database "mytestdb" as user "myuser".

Create a table and insert row(s):

mytestdb=> create table testtable (col1 varchar);
CREATE TABLE
mytestdb=> insert into testtable values('hello');
INSERT 0 1

Select on the table you created:

mytestdb=> select * from testtable;
 col1
-------
 hello
(1 row)

mytestdb=>

Describe table:

mytestdb=> \dt
          List of relations
 Schema |   Name    | Type  | Owner
--------+-----------+-------+--------
 public | testtable | table | myuser
(1 row)

Note that by default the schema used is Public. You should create a specific schema for your users.





By default, the service postgresql-9.1 is added to chkconifg, but all run levels are set to off.

Add for run levels 2,3, and 4 for the postgresql-9.1 service.

[root@server1 yum.repos.d]# chkconfig --level 234 postgresql-9.1 on

Many, if not most, third party software and modules are still be set to look for PoistgreSQL's conf file and data directory under their old (pre-version 9) locations.

You can address this, and make life easier for yourself, by creating a few symlinks from the new locations to the old.

Symlink 1: Symlink for the binary directory. This is particularly useful as this is the location of the pg_config file

root@server1 [~]# ln -s /usr/pgsql-9.1/bin/pg_config /usr/bin

Symlink 2: Symlink for the old data directory location of /var/lob/pgsql

root@server1 [~]# ln -s /var/lib/pgsql/9.1/data /var/lib/pgsql  
root@server1 [~]# ln -s /var/lib/pgsql/9.1/backups /var/lib/pgsql  

Using the postgresql repo, we can easily install PostGIS if we wish to.

The installtion will also install Proj4 and Geos and required perl modules.

[root@server1 yum.repos.d]# yum install postgis91 postgis91-utils
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.us.leaseweb.net
 * extras: mirror.lug.udel.edu
 * updates: centos.mirror.choopa.net
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package postgis91.x86_64 0:1.5.3-2.rhel6 set to be updated
--> Processing Dependency: proj for package: postgis91-1.5.3-2.rhel6.x86_64
--> Processing Dependency: geos for package: postgis91-1.5.3-2.rhel6.x86_64
--> Processing Dependency: libgeos_c.so.1()(64bit) for package: postgis91-1.5.3-2.rhel6.x86_64
--> Processing Dependency: libproj.so.0()(64bit) for package: postgis91-1.5.3-2.rhel6.x86_64
---> Package postgis91-utils.x86_64 0:1.5.3-2.rhel6 set to be updated
--> Processing Dependency: perl-DBD-Pg for package: postgis91-utils-1.5.3-2.rhel6.x86_64
--> Running transaction check
---> Package geos.x86_64 0:3.3.0-1.rhel6 set to be updated
---> Package perl-DBD-Pg.x86_64 0:2.15.1-3.el6 set to be updated
--> Processing Dependency: perl(DBI) for package: perl-DBD-Pg-2.15.1-3.el6.x86_64
---> Package proj.x86_64 0:4.7.0-1.rhel6 set to be updated
--> Running transaction check
---> Package perl-DBI.x86_64 0:1.609-4.el6 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package                Arch          Version               Repository     Size
================================================================================
Installing:
 postgis91              x86_64        1.5.3-2.rhel6         pgdg91        1.3 M
 postgis91-utils        x86_64        1.5.3-2.rhel6         pgdg91         21 k
Installing for dependencies:
 geos                   x86_64        3.3.0-1.rhel6         pgdg91        502 k
 perl-DBD-Pg            x86_64        2.15.1-3.el6          base          197 k
 perl-DBI               x86_64        1.609-4.el6           base          705 k
 proj                   x86_64        4.7.0-1.rhel6         pgdg91        157 k

Transaction Summary
================================================================================
Install       6 Package(s)
Upgrade       0 Package(s)

Total download size: 2.9 M
Installed size: 11 M
Is this ok [y/N]: y
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : proj-4.7.0-1.rhel6.x86_64                                1/6
  Installing     : perl-DBI-1.609-4.el6.x86_64                              2/6
  Installing     : perl-DBD-Pg-2.15.1-3.el6.x86_64                          3/6
  Installing     : geos-3.3.0-1.rhel6.x86_64                                4/6
  Installing     : postgis91-1.5.3-2.rhel6.x86_64                           5/6
  Installing     : postgis91-utils-1.5.3-2.rhel6.x86_64                     6/6

Installed:
  postgis91.x86_64 0:1.5.3-2.rhel6    postgis91-utils.x86_64 0:1.5.3-2.rhel6

Dependency Installed:
  geos.x86_64 0:3.3.0-1.rhel6          perl-DBD-Pg.x86_64 0:2.15.1-3.el6
  perl-DBI.x86_64 0:1.609-4.el6        proj.x86_64 0:4.7.0-1.rhel6

Complete!
[root@server1 yum.repos.d]#

The required PostGIS sql files will be installed under /usr/pgsql-9.1/share/contrib/postgis-1.5

Create a database.

-bash-4.1$ createdb pgisdb
Password:
-bash-4.1$

Run the postgis.sql and spatial_ref_sys.sql files using below.

-bash-4.1$ psql -d pgisdb -f /usr/pgsql-9.1/share/contrib/postgis-1.5/postgis.sql

-bash-4.1$ psql -d pgisdb -f /usr/pgsql-9.1/share/contrib/postgis-1.5/spatial_ref_sys.sql

Due to the directory structure of PostgreSQL 9, you will need to make a few changes to the Webmin management interface it let Webmin know where the Postgre files are located.

Under Servers>PostgreSQL Database Server Click on Module Configuration.

Make the following substitutions in the System Configuration Section:

1. Path to psql command:Original:

  /usr/bin/psql

Change to:

/usr/pgsql-9.1/bin/psql

2. Command to start PostgreSQLOriginal:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb start; else /etc/rc.d/init.d/postgresql start; fi

Change to:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb start; else /etc/rc.d/init.d/postgresql-9.1 start; fi

3. Command to stop PostgreSQL Original:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb stop; else /etc/rc.d/init.d/postgresql stop; fi

Change to:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb stop; else /etc/rc.d/init.d/postgresql-9.1 stop; fi

4. Command to initialize PostgreSQLOriginal:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb start; else /etc/rc.d/init.d/postgresql initdb ; /etc/rc.d/init.d/postgresql start; fi

Change to:

if [ -r /etc/rc.d/init.d/rhdb ]; then /etc/rc.d/init.d/rhdb start; else /etc/rc.d/init.d/postgresql-9.1 initdb ; /etc/rc.d/init.d/postgresql-9.1 start; fi

5. Path to postmaster PID fileOriginal:

/var/run/postmaster.pid

Change to:

/var/run/postmaster-9.1.pid

6. Paths to host access config fileOriginal:

/var/lib/pgsql/data/pg_hba.conf

Change to:

 /var/lib/pgsql/9.1/data/pg_hba.conf

7. Default backup repository directoryOriginal:

 /home/db_repository

Change to:

 /var/lib/pgsql/9.1/backups

Save the configuration.

If you have not already initialized the database, do so now by clicking the initialize database button.

Additional information and references:

Postgresql.Org/

PostgreSQL 9.1 Documentation