Raspbian with PostgreSQL it is quite easy actually. Just like on Ubuntu/Linux Mint/... (Replace the ellipsis with any derivative of Debian or Ubuntu.) The hardest part is to decide which version of the database server to employ. On this page the full set of options for retrieving the server is given with the necessary amount of detail.
"Should I get it?"
Actually, since PostgreSQL (together with MySQL) is one of the most popular open source databases within the Linux realm, some distributions choose to deliver it pre-installed on their releases. If you are not sure, if you need to get the server at all, this simple command can answer that question:
$ ps aux | grep postgers
It will search through the processes running on your system and filter them to leave only those bound to PostgreSQL.
It is possible that the server is present on the system, but it is not running at the moment. In that case it is enough to see if its configurations are in place. The place in question for the 9.1 version of the server is:
/etc/postgresql/9.1/main/
Listing this directory should give out the existence of several important files. Actually the sole existence of the /etc/postgersql folder (and everything below it) is a hint that the PostgerSQL database have been installed on the system.
Different installation processes
When you have to do everything by yourself, the simplest choice is to get the default version form the repository. Currently this is the 9.1 version. The command is trivial, and here you can see an example of the full installation log it gives on Raspbian Wheezy:
$ sudo apt-get install postgresql-9.1
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
libpq5 lsb-release postgresql-client-9.1 postgresql-client-common postgresql-common ssl-cert
Suggested packages:
lsb oidentd ident-server locales-all postgresql-doc-9.1 openssl-blacklist
The following NEW packages will be installed:
libpq5 lsb-release postgresql-9.1 postgresql-client-9.1 postgresql-client-common postgresql-common ssl-cert
0 upgraded, 7 newly installed, 0 to remove and 0 not upgraded.
Need to get 5444 kB of archives.
After this operation, 22,6 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://mirrordirector.raspbian.org/raspbian/ wheezy/main libpq5 armhf 9.1.11-0wheezy1 [520 kB]
Get:2 http://mirrordirector.raspbian.org/raspbian/ wheezy/main lsb-release all 4.1+Debian8+rpi1 [27,1 kB]
Get:3 http://mirrordirector.raspbian.org/raspbian/ wheezy/main postgresql-client-common all 134wheezy4 [63,3 kB]
Get:4 http://mirrordirector.raspbian.org/raspbian/ wheezy/main postgresql-client-9.1 armhf 9.1.11-0wheezy1 [1337 kB]
Get:5 http://mirrordirector.raspbian.org/raspbian/ wheezy/main ssl-cert all 1.0.32 [19,5 kB]
Get:6 http://mirrordirector.raspbian.org/raspbian/ wheezy/main postgresql-common all 134wheezy4 [138 kB]
Get:7 http://mirrordirector.raspbian.org/raspbian/ wheezy/main postgresql-9.1 armhf 9.1.11-0wheezy1 [3339 kB]
Fetched 5444 kB in 6s (848 kB/s)
Preconfiguring packages ...
Selecting previously unselected package libpq5.
(Reading database ... 61782 files and directories currently installed.)
Unpacking libpq5 (from .../libpq5_9.1.11-0wheezy1_armhf.deb) ...
Selecting previously unselected package lsb-release.
Unpacking lsb-release (from .../lsb-release_4.1+Debian8+rpi1_all.deb) ...
Selecting previously unselected package postgresql-client-common.
Unpacking postgresql-client-common (from .../postgresql-client-common_134wheezy4_all.deb) ...
Selecting previously unselected package postgresql-client-9.1.
Unpacking postgresql-client-9.1 (from .../postgresql-client-9.1_9.1.11-0wheezy1_armhf.deb) ...
Selecting previously unselected package ssl-cert.
Unpacking ssl-cert (from .../ssl-cert_1.0.32_all.deb) ...
Selecting previously unselected package postgresql-common.
Unpacking postgresql-common (from .../postgresql-common_134wheezy4_all.deb) ...
Adding 'diversion of /usr/bin/pg_config to /usr/bin/pg_config.libpq-dev by postgresql-common'
Selecting previously unselected package postgresql-9.1.
Unpacking postgresql-9.1 (from .../postgresql-9.1_9.1.11-0wheezy1_armhf.deb) ...
Processing triggers for man-db ...
Setting up libpq5 (9.1.11-0wheezy1) ...
Setting up lsb-release (4.1+Debian8+rpi1) ...
Setting up postgresql-client-common (134wheezy4) ...
Setting up postgresql-client-9.1 (9.1.11-0wheezy1) ...
update-alternatives: using /usr/share/postgresql/9.1/man/man1/psql.1.gz to provide /usr/share/man/man1/psql.1.gz (psql.1.gz) in auto mode
Setting up ssl-cert (1.0.32) ...
Setting up postgresql-common (134wheezy4) ...
Adding user postgres to group ssl-cert
Building PostgreSQL dictionaries from installed myspell/hunspell packages...
Setting up postgresql-9.1 (9.1.11-0wheezy1) ...
Creating new cluster (configuration: /etc/postgresql/9.1/main, data: /var/lib/postgresql/9.1/main)...
Moving configuration file /var/lib/postgresql/9.1/main/postgresql.conf to /etc/postgresql/9.1/main...
Moving configuration file /var/lib/postgresql/9.1/main/pg_hba.conf to /etc/postgresql/9.1/main...
Moving configuration file /var/lib/postgresql/9.1/main/pg_ident.conf to /etc/postgresql/9.1/main...
Configuring postgresql.conf to use port 5432...
update-alternatives: using /usr/share/postgresql/9.1/man/man1/postmaster.1.gz to provide /usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode
[ ok ] Starting PostgreSQL 9.1 database server: main.
The log gives a lot of initial information, and most importantly you can see that after issuing the command and it completes, you already have a running database server. Additional proof of this the output of the ps command mentioned before:
$ ps aux | grep postgres
postgres 4303 1.8 1.9 47400 7420 ? S 01:24 0:05 /usr/lib/postgresql/9.1/bin/postgres -D /var/lib/postgresql/9.1/main -c config_file=/etc/postgresql/9.1/main/postgresql.conf
postgres 4311 0.0 0.4 47400 1712 ? Ss 01:24 0:00 postgres: writer processpostgres 4312 0.0 0.3 47400 1528 ? Ss 01:24 0:00 postgres: wal writer processpostgres 4313 0.0 0.6 47820 2424 ? Ss 01:24 0:00 postgres: autovacuum launcher processpostgres 4314 0.0 0.3 17496 1460 ? Ss 01:24 0:00 postgres: stats collector processpi 4350 0.0 0.2 5244 836 pts/0 S+ 01:29 0:00 grep --color=auto postgres
Alternatively, if you want the latest and greatest edition (currently this is version 9.3.1 - nearly two months old now), you'll have to try and build it from sources. The option for adding the PostgreSQL's own repositories is not viable, because there are no packages in there dedicated to the ARM architecture.
Next is the initial administration
Currently, the only user known to the database is the default superuser named postgres. The specific thing about this user is that its password is literally unknown in the beginning. So it, at least, must be set for the sake of simple security. This is relatively easy process consisting in two basic steps.
As a privileged user of the operating system (with the sudo command), you have to open this very important configuration file - /etc/postgresql/9.1/main/pg_hba.conf. The piece of text is the ultimate conveyor of who and how will connect to your database. Rules are clear and simple, but strong and provide for efficient security on the network level. I won't go in much more detail about its contents, for there already are pretty good sources of information (like this one). In short the following line:
The second step is to set the password. The following log shows the necessary commands and the the output:
Currently, the only user known to the database is the default superuser named postgres. The specific thing about this user is that its password is literally unknown in the beginning. So it, at least, must be set for the sake of simple security. This is relatively easy process consisting in two basic steps.
As a privileged user of the operating system (with the sudo command), you have to open this very important configuration file - /etc/postgresql/9.1/main/pg_hba.conf. The piece of text is the ultimate conveyor of who and how will connect to your database. Rules are clear and simple, but strong and provide for efficient security on the network level. I won't go in much more detail about its contents, for there already are pretty good sources of information (like this one). In short the following line:
local all postgres peerhave to be changed to this:
local all postgres trustThis gives you a complete password-less access to the superuser from the localhost for the time being.
The second step is to set the password. The following log shows the necessary commands and the the output:
$ sudo -u postgres psql postgres
[sudo] password for user: psql (9.3.2)Type "help" for help.
postgres=# \password postgres Enter new password: Enter it again: postgres=# \q
As a final sub-step and to keep things secure, the line in the configuration file is good to be changed again. The word trust that we introduced, can be changed to md5. This means that the access to the superuser will be allowed only with password, even on the localhost.
In order for these changes to be applied, the configuration have to be reloaded (no need to restarting PostgreSQL server, when you've changed only the configuration). From the several possible methods, the following worked fine for me:
In order for these changes to be applied, the configuration have to be reloaded (no need to restarting PostgreSQL server, when you've changed only the configuration). From the several possible methods, the following worked fine for me:
$ sudo service postgresql reload
* Reloading PostgreSQL 9.1 database server [ OK ]
Further on things become quite specific with the different types of host access, graphical and command line clients, etc. And it's all up to you.
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