PostgreSQL (简体中文)

PostgreSQL是一个开源的，社区驱动的，符合标准的 对象-关系型 数据库系统。

本文档介绍如何安装PostgreSql，以及如何与PHP 和 Apache进行交互。同时，也介绍了如何配置PostgreSql，以使得远程服务端能够操作之。此处默认PHP和Apache 已经安装并配置完毕，如果您恰好没有安装此两个软件，请参考LAMP。

开始之前

有些地方会有“以 postgres 用户身份”的指示。如果已经安装 sudo，请执行以下操作，以 postgres 用户获得一个 shell：

sudo -i -u postgres

否则，使用 su 命令：

su root
su - postgres

安装PostgreSQL

安装 postgresql

Create the file tmpfiles.d for /run/postgresql:

# systemd-tmpfiles --create postgresql.conf

创建数据文件夹(acordingly with the PGROOT variable set before in the config file)

# mkdir /var/lib/postgres/data

设置用户'postgres'为 /var/lib/postgres/data 的所有者

# chown -c postgres:postgres /var/lib/postgres/data

以'postgres'用户身份初始化数据库(本文件的说明，第一款如何作为postgres用户):

$ initdb -D '/var/lib/postgres/data'

启动PostgreSQL

# systemctl start postgresql

(可选) 添加 PostgreSQL 到daemons列表里, 使系统启动时，postgresql作为守护进程同时启动

# systemctl enable postgresql

创建第一个数据库/用户

以postgres用户身份, 添加一个新的数据库用户使用createuser 命令

如果一个创建与你的Arch用户($USER)同名的数据库用户，并允许访问PostgreSQL数据库的shell，那么在使用PostgreSQL数据库shell的时候无需指定用户登录（这样做会比较方便）。

例如:创建一个超级用户

$ createuser -s -U postgres --interactive

输入要增加的角色名称: 我登录Arch的用户名

以具备读写权限的用户身份，创建一个新的数据库,使用createdb 命令。

从你的shell ( 不是 以postrgres用户的身份)

$ createdb myDatabaseName

熟悉PostgreSQL

Access the database shell

• Become the postgres user the first time, so we can assign permissions to you (your primary user)

$ sudo su postgres

• Start the primary db shell, where you can do all your creation of databases/tables, deletion, set permissions, and run raw SQL commands.

$ psql

--You can optionally use `psql <database_name>` to administer an individual database.

• 连接一个特定的数据库

=> \c <database>

• 列出所有的用户和他们的相关权限级别

=> \du

• 显示当前数据库的总况

=> \dt

There are of course many more meta-commands, but these should help you get started.

Configure PostgreSQL to be accessible from remote

The PostgreSQL database server configuration file is postgresql.conf. This file is located in the data directory of the server, typically /var/lib/postgres/data. This folder also houses the other main config files, including the pg_hba.conf.

Note: By default this folder will not even be browseable (or searchable) by a regular user, if you are wondering why `find` or `locate` isn't finding the conf files, this is the reason (threw me for a loop the first time I installed).

1. As root user edit the file
   

   $ sudo vim /var/lib/postgres/data/postgresql.conf

2. In the connections and authentications section uncomment or edit the listen_addresses line to your needs
   

   listen_addresses = '*'

   and take a careful look at the other lines.
3. Hereafter insert the following line in the host-based authentication file /var/lib/postgres/data/pg_hba.conf. This file controls which hosts are allowed to connect, so be careful.
   

   # IPv4 local connections: <br>host   all   all   your_desired_ip_address/32   trust

   whereas your_desired_ip_address is the ip address of the client.
4. After this you should restart the daemon process for the changes to take effect with
   

   $ sudo /etc/rc.d/postgresql restart

Note: Postgresql uses port 5432 by default for remote connections. So make sure this port is open and able to receive incoming connections

For troubleshooting take a look in the server log file

tail /var/log/postgresql.log

Configure PostgreSQL to Work With PHP

1. Install the PHP-PostgreSQL modules

   $ pacman -S php-pgsql 

2. Open the file /etc/php/php.ini with your editor of choice, e.g.,

   # vim /etc/php/php.ini

3. Find the line that starts with, ";extension=pgsql.so" and change it to, "extension=pgsql.so". (Just remove the preceding ";"). If you need PDO, do the same thing with ";extension=pdo.so" and ";extension=pdo_pgsql.so". If this lines are not present, add it. This lines may be in the "Dynamic Extensions" section of the file, or toward the very end of the file.
4. Restart the Apache web server

   # /etc/rc.d/httpd restart

Installing phpPgAdmin (optional)

phpPgAdmin is a web-based administration tool for PostgreSQL. It can be installed two ways.

Option A: install via Pacman (preferred)

1. Make sure that the [community] repo is enabled.
2. Install the package via Pacman

   # pacman -S phppgadmin

Option B: install via a manual install (the old way)

1. Download the latest .bz2 file from here into the root of your server directory

   wget -P /home/httpd/html http://downloads.sourceforge.net/phppgadmin/phpPgAdmin-4.1.3.tar.bz2

2. Extract the file into the new directory

   tar -C /home/httpd/html/ -jxvf /home/httpd/html/phpPgAdmin-4.1.3.tar.bz2

3. Remove the tar file

   rm /home/httpd/html/phpPgAdmin-4.1.3.tar.bz2

4. Change the name of the directory created in the previous step to include the version number (this will help in the future when upgrading)

   mv /home/httpd/html/phpPgAdmin /home/httpd/html/phpPgAdmin-4.1.3/

5. Create a link to that directory (for ease of linking and upgrading)

   ln -s /home/httpd/html/phpPgAdmin-4.1.3/ /home/httpd/html/phpPgAdmin

6. Copy the included generic config file

   cp /home/httpd/html/phpPgAdmin/conf/config.inc.php-dist /home/httpd/html/phpPgAdmin/conf/config.inc.php

The config file is located at /home/httpd/html/phpPgAdmin/conf/config.inc.php. No changes should be required. Check this page for any other setup questions that you might have.

Postgresql升级配置

Warning: Official postgresql upgrade documentation should be followed.

首先要明确:这个说明可能导致数据丢失，因此，后果自负.即使这个在我这边没问题，也不代表其他所有的服务器都会没问题。

最好是在/etc/pacman.conf里加上下面这行：

IgnorePkg = postgresql

This will make sure that you don't accidentally upgrade the database to an incompatible version. If you did an accidental upgrade you might not be able to access any of your data. Always check the Postgresql home page (http://www.postgresql.org/) to be sure of what steps are required for each upgrade. For a bit about why this is the case see this.

How to dump all of your data, upgrade PostgreSQL, and then restore all of your data (this may not be necessary for every upgrade, see #2 above)

Become the root user

su

Become the postgres user

su postgres

Change the current directory to one that the postgres user can write to

eg. cd ~/data/

Dump the current contents of the database

pg_dumpall > pgs_db.out

Unless you have a .pgpass file setup, you will be required to enter your password a few times (the number of times is roughly equal to the number of databases that you have + 2). One problem occurs if you don't have a password defined for the postgres user but you require local users to authenticate. In this case you will be asked to give a password that doesn't exist. To work around this problem, add a line to your pg_hba.conf file to trust the postgres user. You can remove this line after the upgrade is complete. So, the first line of the 'local' section of pg_hba.conf would look something like this:

local     all postgres                                trust

Log out of the postgres user and return to superuser

exit

停止PostgreSQL服务器

/etc/rc.d/postgresql stop

移走Postgresql数据目录

mv /var/lib/postgres /var/lib/postgres_old

升级postgresql

pacman -S postgresql

启动PostgreSQL服务器

/etc/rc.d/postgresql start

切换为postgres用户

su postgres

Change the current directory to the directory that you dumped the data out to (in step 4 above)

eg. cd /var/lib/postgres_old/data/

Restore the database

psql -e template1 -f pgs_db.out

More Resources

• Official PostgreSQL Homepage