pg数据库安装

 1. yum update -y
 
 2. sudo yum install epel-release -y
 
 3. zlib 在PSQL中pg_dump和pg_restort中压缩文档需要用到该包
 yum install -y zlib.x86_64 zlib-devel.x86_64
 
 4. Install the repository RPM:
 sudo yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
 
 5. # Install PostgreSQL:
sudo yum install -y postgresql15-server

6.初始化数据库
/usr/pgsql-15/bin/postgresql-15-setup initdb

7.设置数据库开机自动启动后启动数据库
systemctl enable postgresql-15
systemctl start  postgresql-15

8.检查postgresql数据库的操作系统用户
cat /etc/passwd

9.切换至postgres用户
su -  postgres

10.启动PGSQL 
psql

11退出到操作系统下,看下后台进程
top -b -u postgres -d 1 -n 1 -c
展示内容：
top - 16:35:46 up 25 min,  1 user,  load average: 0.30, 0.34, 0.28
Tasks: 146 total,   1 running, 145 sleeping,   0 stopped,   0 zombie
%Cpu(s):  1.2 us,  6.0 sy,  0.0 ni, 91.6 id,  1.2 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  7906204 total,  5118488 free,  1029596 used,  1758120 buff/cache
KiB Swap:  8257532 total,  8257532 free,        0 used.  6600712 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 2977 postgres  20   0  402048  17576  16124 S   0.0  0.2   0:00.06 /usr/pgsql-15/bin/postmaster -D /var/lib/pgsql/15/data/
 2979 postgres  20   0  253252   2108    688 S   0.0  0.0   0:00.00 postgres: logger
 2980 postgres  20   0  402200   2316    800 S   0.0  0.0   0:00.00 postgres: checkpointer
 2981 postgres  20   0  402184   3360   1856 S   0.0  0.0   0:00.02 postgres: background writer
 2983 postgres  20   0  402184   6268   4768 S   0.0  0.1   0:00.01 postgres: walwriter
 2984 postgres  20   0  403668   3344   1576 S   0.0  0.0   0:00.00 postgres: autovacuum launcher
 2985 postgres  20   0  403652   3084   1352 S   0.0  0.0   0:00.00 postgres: logical replication launcher

12.需更改pg_hba.conf文件,在#IPv4下加入 对IP的管理，0/0代表可以任意IP登录，生产环境请限指定IP段
vi /var/lib/pgsql/15/data/pg_hba.conf

修改内容如下：
# IPv4 local connections:
host    all             all             127.0.0.1/32            scram-sha-256
host    all             all             0/0                     md5

13.修改postgresq.conf文件，将listen_addresses改为* 
vi /var/lib/pgsql/15/data/postgresql.conf 

修改内容如下：
listen_addresses = '*'

14.修改登录PostgreSQL密码
su -  postgres
psql
ALTER USER postgres WITH PASSWORD 'xxxxxxxxxxx';
返回：
ALTER ROLE
注：
密码postgres要用引号引起来,命令最后有分号

15.开放端口
firewall-cmd --zone=public --add-port=5432/tcp --permanent
firewall-cmd --reload

16.重启数据库：
systemctl restart  postgresql-15