Mysql socket连接测试

配置如下：
socket = /data/mysql/data/mysql.sock  //套接字文件

在数据库没有任何连接的情况下，可以看到3306端口和socket端口都在监听

[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an | grep -i 3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN     
[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an |grep -i /tmp/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     1958079570 /tmp/mysql.sock

窗口1：
[mysql@t3-dtpoc-dtpoc-web04 bin]$ ./mysql -protocol=socket -uroot -p
窗口2:
[mysql@t3-dtpoc-dtpoc-web04 bin]$ ./mysql -protocol=socket -uroot -p

可以看到多了两个socket连接，但是3306端口没有连接
[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an | grep -i 3306          
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN     
[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an |grep -i /tmp/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     1958079570 /tmp/mysql.sock
unix  3      [ ]         STREAM     CONNECTED     1959434943 /tmp/mysql.sock
unix  3      [ ]         STREAM     CONNECTED     1959434940 /tmp/mysql.sock
[mysql@t3-dtpoc-dtpoc-web04 bin]$ 

窗口3：指定IP连接
[mysql@t3-dtpoc-dtpoc-web04 bin]$ ./mysql -u root -p -h 127.0.0.1
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 5.7.26-log MySQL Community Server (GPL)

Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

可以看到3306端口已连接
[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an | grep -i 3306          
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:45010         127.0.0.1:3306          ESTABLISHED
tcp        0      0 127.0.0.1:3306          127.0.0.1:45010         ESTABLISHED
[mysql@t3-dtpoc-dtpoc-web04 bin]$ netstat -an |grep -i /tmp/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     1958079570 /tmp/mysql.sock
unix  3      [ ]         STREAM     CONNECTED     1959434943 /tmp/mysql.sock
unix  3      [ ]         STREAM     CONNECTED     1959434940 /tmp/mysql.sock