Python连接openGauss及问题解决

一. openGauss单机版安装

硬件及软件环境：

硬件环境：虚拟机的内存8GB，4核心CPU，900G磁盘（非必须）

软件环境：CentOS7.6

数据库版本：opengauss2.0企业版：openGauss-2.0.0-CentOS-64bit-all.tar.gz

注：内存一定要8G以上，不然没有足够的内存安装会失败。

安装步骤：

1.1. 关闭防火墙

#停止firewall
systemctl stop firewalld.service
#禁止firewall开机启动 
systemctl disable firewalld.service
#检查防火墙是否关闭。
 systemctl status firewalld
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说明：

若防火墙状态显示为active (running)，则表示防火墙未关闭。

若防火墙状态显示为inactive (dead)，则无需再关闭防火墙。

1.2. 设置时区和时间

将各数据库节点的时区设置为相同时区，可以将/usr/share/zoneinfo/目录下的时区文件拷贝为/etc/localtime文件。

cp /usr/share/zoneinfo/Asia/Shanghai  /etc/localtime

1.3. 关闭SELinux 

[root@node1 ~]#

getenforce
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
setenforce 0
getenforce
#检查
 cat /etc/selinux/config|grep SELINUX
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输出：

# SELINUX= can take one of these three values:

SELINUX=disabled

# SELINUXTYPE= can take one of three values:

SELINUXTYPE=targeted

[root@node1 ~]#

1.4. 修改/etc/hosts

#添加一行

cat >>/etc/hosts <<EOF
192.168.183.28 node1
EOF
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1.5. 配置库路径

cat>> /etc/profile<<EOF
export LD_LIBRARY_PATH=/opt/software/openGauss/script/gspylib/clib:$LD_LIBRARY_PATH
EOF
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1.6. 关闭os交换区

编辑/etc/fstab文件，将交换区的那一行注释掉

vi /etc/fstab

:wq保存退出vi

 临时关闭交换区命令：

swapoff -a
free
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1.7. 设置root用户远程登陆

sed -i "s/#Banner none/Banner none/g" /etc/ssh/sshd_config
cat >>/etc/ssh/sshd_config<<EOF
PermitRootLogin yes
EOF
 systemctl restart sshd
#检查
cat /etc/ssh/sshd_config  | grep PermitRootLogin
cat /etc/ssh/sshd_config | grep Banner
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如下显示修改正确：

PermitRootLogin yes

Banner none

1.8. 文件系统参数、系统支持的最大进程数

echo "* soft nofile 1000000" >>/etc/security/limits.conf 
echo "* hard nofile 1000000" >>/etc/security/limits.conf
echo "* soft nproc unlimited" >>/etc/security/limits.conf 
echo "* hard nproc unlimited" >>/etc/security/limits.conf 
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1.9. 安装python3.6.x

yum install openssl* -y
yum install python3* -y
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检查

[omm@node1 dn]$ python3 -V
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Python 3.6.8

其他软件包，如需要可以安装（也可以直接使用安装）：

yum install -y libaio-devel flex bison ncurses-devel glibc-devel patch redhat-lsb-core readline-devel 
yum install openssl* -y
yum install -y java-1.8.0-openjdk* psmisc bzip2 python3 python3-devel lksctp*
reboot   #重新启动服务器 
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1.10. 创建安装包的存放目录

mkdir -p /opt/software/openGauss
chmod 755 -R /opt/software
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1.11. 下载openGauss数据库软件

下载地址为：https://opengauss.org/zh/download.html

下载完成后上传到centos中。 

1.12. 解压缩openGauss DBMS介质

cd /opt/software/openGauss
tar -zxvf openGauss-2.0.0-CentOS-64bit-all.tar.gz
tar -zxvf openGauss-2.0.0-CentOS-64bit-om.tar.gz
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1.13. 创建XML文件

下面是xml文件官方模板，一般只需要改一下自己centos机器的IP

cat > clusterconfig.xml<<EOF 
<?xml version="1.0" encoding="UTF-8"?>
<ROOT>
    <!-- openGauss整体信息 -->
    <CLUSTER>
        <!-- 数据库名称 -->
        <PARAM name="clusterName" value="dbCluster" />
        <!-- 数据库节点名称(hostname) -->
        <PARAM name="nodeNames" value="node1" />
        <!-- 数据库安装目录-->
        <PARAM name="gaussdbAppPath" value="/opt/huawei/install/app" />
        <!-- 日志目录-->
        <PARAM name="gaussdbLogPath" value="/var/log/omm" />
        <!-- 临时文件目录-->
        <PARAM name="tmpMppdbPath" value="/opt/huawei/tmp" />
        <!-- 数据库工具目录-->
        <PARAM name="gaussdbToolPath" value="/opt/huawei/install/om" />
        <!-- 数据库core文件目录-->
        <PARAM name="corePath" value="/opt/huawei/corefile" />
        <!-- 节点IP，与数据库节点名称列表一一对应 -->
        <PARAM name="backIp1s" value="192.168.183.28"/>
    </CLUSTER>
    <!-- 每台服务器上的节点部署信息 -->
    <DEVICELIST>
        <!-- 节点1上的部署信息 -->
        <DEVICE sn="node1">
            <!-- 节点1的主机名称 -->
            <PARAM name="name" value="node1"/>
            <!-- 节点1所在的AZ及AZ优先级 -->
            <PARAM name="azName" value="AZ1"/>
            <PARAM name="azPriority" value="1"/>
            <!-- 节点1的IP，如果服务器只有一个网卡可用，将backIP1和sshIP1配置成同一个IP -->
            <PARAM name="backIp1" value="192.168.183.28"/>
            <PARAM name="sshIp1" value="192.168.183.28"/>
    <!--dbnode-->
    <PARAM name="dataNum" value="1"/>
    <PARAM name="dataPortBase" value="26000"/>
    <PARAM name="dataNode1" value="/opt/huawei/install/data/dn"/>
            <PARAM name="dataNode1_syncNum" value="0"/>
        </DEVICE>
    </DEVICELIST>
</ROOT>
EOF
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1.14. 检查环境变量

echo $LD_LIBRARY_PATH
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1.15. 安装前进行交互式检查

[root@node1 script]#  ./gs_preinstall -U omm -G dbgrp -X /opt/software/openGauss/clusterconfig.xml
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出现以下内容代表检查没问题。

 Parsing the configuration file.

Successfully parsed the configuration file.
Installing the tools on the local node.
Successfully installed the tools on the local node.
Setting pssh path
Successfully set core path.
Are you sure you want to create the user[omm] and create trust for it (yes/no)? yes
Please enter password for cluster user.
Password: omm123
Please enter password for cluster user again.
Password: omm123
Successfully created [omm] user on all nodes.
Preparing SSH service.
Successfully prepared SSH service.
Checking OS software.
Successfully check os software.
Checking OS version.
Successfully checked OS version.
Creating cluster's path.
Successfully created cluster's path.
Setting SCTP service.
Successfully set SCTP service.
Set and check OS parameter.
Setting OS parameters.
Successfully set OS parameters.
Warning: Installation environment contains some warning messages.
Please get more details by "/opt/software/openGauss/script/gs_checkos -i A -h node1 --detail".
Set and check OS parameter completed.
Preparing CRON service.
Successfully prepared CRON service.
Setting user environmental variables.
Successfully set user environmental variables.
Setting the dynamic link library.
Successfully set the dynamic link library.
Setting Core file
Successfully set core path.
Setting pssh path
Successfully set pssh path.
Set ARM Optimization.
No need to set ARM Optimization.
Fixing server package owner.
Setting finish flag.
Successfully set finish flag.
Preinstallation succeeded
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1.16. 开始安装openGauss DBMS和创建数据库

使用root执行如下命令

cd /opt/software/openGauss/script
chmod -R 755 /opt/software/openGauss/script
chown -R omm:dbgrp /opt/software/openGauss/script
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使用omm用户安装openGauss DBMS和创建openGauss数据库

su - omm
cd /opt/software/openGauss/script
cp ../clusterconfig.xml .
gs_install -X /opt/software/openGauss/script/clusterconfig.xml
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重要提示：用户需根据提示输入数据库的密码，密码需要具有一定的复杂度，为保证用户正常使用该数据库，请记住输入的数据库密码。此处建议密码设置为huawei@1234

[omm@node1 ~]$ cd /opt/software/openGauss/script
[omm@node1 script]$ cp ../clusterconfig.xml .
[omm@node1 script]$ gs_install -X /opt/software/openGauss/script/clusterconfig.xml
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Parsing the configuration file.
Check preinstall on every node.
Successfully checked preinstall on every node.
Creating the backup directory.
Successfully created the backup directory.
begin deploy..
Installing the cluster.
begin prepare Install Cluster..
Checking the installation environment on all nodes.
begin install Cluster..
Installing applications on all nodes.
Successfully installed APP.
begin init Instance..
encrypt cipher and rand files for database.
Please enter password for database:huawei@1234
Please repeat for database:huawei@1234
begin to create CA cert files
The sslcert will be generated in /opt/huawei/install/app/share/sslcert/om
Cluster installation is completed.
Configuring.
Deleting instances from all nodes.
Successfully deleted instances from all nodes.
Checking node configuration on all nodes.
Initializing instances on all nodes.
Updating instance configuration on all nodes.
Check consistence of memCheck and coresCheck on database nodes.
Configuring pg_hba on all nodes.
Configuration is completed.
Successfully started cluster.
Successfully installed application.
end deploy..
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查看数据库状态：

[omm@node1 script]$ gs_om -t status
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会出现以下内容:

 -----------------------------------------------------------------------

cluster_name    : dbCluster
cluster_state   : Normal
redistributing  : No
---------------------------------------------------------------------
[omm@node1 script]$
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启动数据库（安装完默认已经启动）：

[omm@node1 db1]$ gs_om -t start
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Starting cluster.

=========================================

[SUCCESS] node1:

[2021-04-01 16:50:13.969][29784][][gs_ctl]: gs_ctl started,datadir is /opt/huawei/install/data/dn

[2021-04-01 16:50:13.974][29784][][gs_ctl]:  another server might be running; Please use the restart command

=========================================

Successfully started.

使用omm用户执行下面的操作。

登录到数据库，

gsql -d postgres -p 26000 -r
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#执行上条命令会出现以下提示内容。gsql ((openGauss 2.0.0 build 78689da9) compiled at 2021-03-31 21:04:03 commit 0 last mr  )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
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其他基本的命令

\q  #退出会话
gs_om  -t stop #关闭数据库
gs_om  -t restart  #重启数据库
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二.Python连接openGauss

以下环境也在centos7.6中。

遇到过的问题踩坑记录：解决过程：

    第一次远程连接openGauss时使用的是omm初始用户，结果报错：不允许使用omm用户来远程连接

    为此我们新建一个gem用户。

    新建用户gem: 

    CREATE USER gem with sysadmin PASSWORD 'huawei@1234';

    配置文件/opt/huawei/install/data/dn/pg_hba.conf 追加：host all all 0.0.0.0/0 sha256 ，如下图所示：

    其中，第一个all代表任意数据库   第二个all代表任何用户(除了初始用户)   0.0.0.0/0代表任意主机  加密仅支持sha256。

    修改配置后重启数据库：

        gs_om -t restart

2.1 安装python相关依赖包

python可以借助jaydebeapi第三方库来连接openGauss，搭建过程如下：

 pip3 install prometheus_client
 pip3 install Jpype1
 pip3 install jaydebeapi
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import jaydebeapi
url = 'jdbc:postgresql://192.168.183.28:26000/postgres'
user = 'gem'
password = 'huawei@1234'
dirver = 'org.postgresql.Driver'
jarFile = '/root/postgresql.jar'
sqlStr = """SELECT 666;"""
conn = jaydebeapi.connect(dirver, url, [user, password], jarFile)
curs = conn.cursor()
curs.execute(sqlStr)
result = curs.fetchall()
print(result)
curs.close()
conn.close()
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[(666,)]
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