一、安装准备
需要安装的包：
yum install postgresql95-devel-9.5.5-1PGDG.rhel6.x86_64.rpm
文件可以从官网下载。http://yum.postgresql.org/repopackages.php
操作系统：
CentOS release 6.3 (Final)
安装时如果提示yum源不对，注意调整rpm源如下：
[root@mdw yum.repos.d]# cat pgdg-95-redhat.repo
[pgdg95]
name=PostgreSQL 9.5 $releasever - $basearch
baseurl=https://download.postgresql.org/pub/repos/yum/9.5/redhat/rhel-$releasever-$basearch
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-PGDG-95
[pgdg95-source]
name=PostgreSQL 9.5 $releasever - $basearch - Source
failovermethod=priority
baseurl=https://download.postgresql.org/pub/repos/yum/srpms/9.5/redhat/rhel-$releasever-$basearch
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-PGDG-95
二、开始安装：
yum install postgresql95-devel-9.5.5-1PGDG.rhel6.x86_64.rpm
yum install postgresql95-server postgresql95-contrib
三、初始化数据库：
mkdir -p /data/postgres/pgsql/data
chown -R postgres.postgres /data/postgres/
（1）先切换到postgres用户
[root@mdw yum.repos.d]# su - postgres
（2）如果初始化成功，会有如下提示：
-bash-4.1$ /usr/pgsql-9.5/bin/initdb -D /data/postgres/pgsql/data
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.
The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".
Data page checksums are disabled.
fixing permissions on existing directory /data/postgres/pgsql/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
creating template1 database in /data/postgres/pgsql/data/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating collations ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
loading PL/pgSQL server-side language ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok
syncing data to disk ... ok
WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.
Success. You can now start the database server using:
/usr/pgsql-9.5/bin/pg_ctl -D /data/postgres/pgsql/data -l logfile start
-bash-4.1$
四、启动数据库：
$ /usr/pgsql-9.5/bin/pg_ctl -D /data/postgres/pgsql/data -l /tmp/postrest.log start
server starting
五、创建db
createdb mysql2gp_sy
六、登录数据库：
$ psql -h 127.0.0.1 -d mysql2gp_sy -U postgres
psql (9.5.6)
Type "help" for help.
mysql2gp_sy=#
至此，安装成功。