【MySQL】如何使用Shared-memory协议(Windows)连接MySQL数据库

连接MySQL的协议

在MySQL中可以通过指定 --protocol参数，选择连接MySQL的协议。

连接协议（Connection Protocals）：

--protocol={TCP|SOCKET|PIPE|MEMORY}TCP/IP  (ALL)  -Transmission Control Protocal/Internet Protocal-Connection:local & remote-Supports Clasic & X protocol
Socket  file (Unix including Linux/Mac) -Connection:local -Supports Clasic & X protocol
Named Pipe    (Win)  -Connection:local -Supports Clasic
Shared Memory (Win)  -Connection:local -Supports Clasic

参考：
https://dev.mysql.com/doc/refman/8.0/en/connection-options.html#option_general_protocol
>4.2.3 Command Options for Connecting to the Server

使用Shared-memory协议(Windows)连接MySQL

在Windows环境中支持共享内存（Shared-memory）连接连接MySQL。
如果服务器启用了Shared-memory连接，客户端就可以通过使用–protocol=MEMORY选项使用Shared-memory连接MySQL。

使用Shared-memory协议(Windows)连接MySQL时，能够提高MySQL的性能，具体测评请参考如下官方链接的介绍。

参考：
Improving the Performance of MySQL on Windows
https://dev.mysql.com/blog-archive/improving-the-performance-of-mysql-on-windows/

步骤1：确认MySQL服务器已启用Shared-memory连接

查看是否启用Shared-memory连接。

mysql> show variables like 'shared_memory';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| shared_memory | OFF   |
+---------------+-------+
1 row in set, 1 warning (0.03 sec)mysql>

如果值是ON，则表示启用；OFF表示禁用状态。

启动Shared-memory连接方法

1. 打开配置文件my.ini，将shared-memory变量和shared-memory-base-name变量前的注释去掉并保存。

例：

# The next three options are mutually exclusive to SERVER_PORT below.
# skip-networking
# enable-named-pipeshared-memoryshared-memory-base-name=MYSQL

※　my.ini文件的位置可以通过【mysql --help】命令中的Default options内容查看。
例：

Default options are read from the following files in the given order:
C:\windows\my.ini C:\windows\my.cnf C:\my.ini C:\my.cnf E:\Soft\MySQL8.0\my.ini E:\Soft\MySQL8.0\my.cnf```

2. 重新启动MySQL服务器。

net stop <MySQL服务名>
net start <MySQL服务名>

例：

C:\Users\Administrator>net stop mysql80
MySQL80 服务正在停止.
MySQL80 服务已成功停止。C:\Users\Administrator>net start mysql80
MySQL80 服务正在启动 ..
MySQL80 服务已经启动成功。

3.查看shared-memory连接启用状态。

C:\Users\Administrator>mysql  -u root -p
Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.28 MySQL Community Server - GPLCopyright (c) 2000, 2022, Oracle and/or its affiliates.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.mysql>  show variables like 'shared_memory';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| shared_memory | ON    |
+---------------+-------+
1 row in set, 1 warning (0.01 sec)mysql>

步骤2：客户端使用shared-memory连接MySQL服务器。

例1：客户端使用shared-memory连接MySQL服务器

通过指定–protocol=MEMORY，客户端可以使用shared-memory连接MySQL服务器。

C:\Users\Administrator>mysql --protocol=MEMORY -u root -p
Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.28 MySQL Community Server - GPLCopyright (c) 2000, 2022, Oracle and/or its affiliates.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.mysql> \s
--------------
mysql  Ver 8.0.28 for Win64 on x86_64 (MySQL Community Server - GPL)Connection id:          9
Current database:
Current user:           root@localhost
SSL:                    Not in use
Using delimiter:        ;
Server version:         8.0.28 MySQL Community Server - GPL
Protocol version:       10
Connection:             Shared memory: MYSQL
Server characterset:    utf8mb4
Db     characterset:    utf8mb4
Client characterset:    gbk
Conn.  characterset:    gbk
TCP port:               0
Binary data as:         Hexadecimal
Uptime:                 1 min 58 secThreads: 2  Questions: 12  Slow queries: 0  Opens: 134  Flush tables: 3  Open tables: 53  Queries per second avg: 0.101
--------------mysql>

例2：默认连接MySQL服务器

启用shared-memory连接后，不指定–protocol时本地连接也会使用shared-memory连接MySQL服务器。

C:\Users\Administrator>mysql  -u root -p
Enter password: ********
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 8.0.28 MySQL Community Server - GPLCopyright (c) 2000, 2022, Oracle and/or its affiliates.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.mysql> \s
--------------
mysql  Ver 8.0.28 for Win64 on x86_64 (MySQL Community Server - GPL)Connection id:          10
Current database:
Current user:           root@localhost
SSL:                    Not in use
Using delimiter:        ;
Server version:         8.0.28 MySQL Community Server - GPL
Protocol version:       10
Connection:             Shared memory: MYSQL
Server characterset:    utf8mb4
Db     characterset:    utf8mb4
Client characterset:    gbk
Conn.  characterset:    gbk
TCP port:               0
Binary data as:         Hexadecimal
Uptime:                 3 min 52 secThreads: 2  Questions: 17  Slow queries: 0  Opens: 134  Flush tables: 3  Open tables: 53  Queries per second avg: 0.073
--------------mysql>

常见错误

当服务器shared memory连接未启用的时候，使用shared memory连接会报如下的错误：

C:\Users\Administrator>mysql --protocol=MEMORY -u root -p
Enter password: ********
ERROR 2038 (HY000): Can't open shared memory; client could not create request event (2)

可参考如上的方法在服务器端进行相应的配置。

小结

本文介绍了在Windows环境中，如何使用shared memory协议连接MySQL数据库的方法。