Docker部署mysql并实现主从复制

mysql多实例

概述

1.MySql多实例是指安装MySql之后，可以再一台linux服务器上同时启动多个MySql数据库（实例），不需要安装多个MySql；
2.如果是有多台Linux服务器，那么我们需要每台服务器分别安装；
3.在一台Linux服务器上启动多个MySql数据库（实例），通过为各个数据库实例配置独立的配置文件来实现，即每个数据库实例有自己单独的配置文件；

配置

1.在Mysql安装主目录下创建/data/3307,/data/3308,/data/3309,/data/3310,四个目录；
2.执行数据库初始化，在Mysql的/usr/local/mysql-5.7.18/bin目录下执行命令：

 mysqld --initialize-insecure --basedir=/use/local/mysql-5.7.18 --datadir=/usr/local/mysql-5.7.18/data/3307 --user=mysql
 mysqld --initialize-insecure --basedir=/use/local/mysql-5.7.18 --datadir=/usr/local/mysql-5.7.18/data/3308 --user=mysql
 mysqld --initialize-insecure --basedir=/use/local/mysql-5.7.18 --datadir=/usr/local/mysql-5.7.18/data/3309 --user=mysql
 mysqld --initialize-insecure --basedir=/use/local/mysql-5.7.18 --datadir=/usr/local/mysql-5.7.18/data/3310 --user=mysql

3.在/data/3307,/data/3308,/data/3309,/data/3310,四个目录下分别创建一个my.cnf文件；
4.配置四个Mysql数据库服务的my.cnf文件；

主从复制

原理

1.master主服务器上的数据发生改变时，则将其改变写入二进制日志文件中；
2.salve从服务器会在一定时间间隔内对master主服务器上的二进制日志进行探测，探测其是否发生过改变；
3.如果发生了改变，则开始一个I/O Thread请求master二进制事件；
4.同时master主服务器为每个I/O Thread启动一个dump Thread，用于向其发送二进制事件；
5.slave从服务器将接收到的二进制事件保存至自己本地的中继日志文件中；
6.salve从服务器将启动SQL Thread从中继日志中读取二进制日志，在本地重放，使得其数据和主服务器保持一致；
7.最后I/O Thread和SQL Thread将进入睡眠状态，等待下一次被唤醒；

主从搭建

节点信息

主节点	端口	对应的从节点	端口
master1	3306	slave1	3307
master2	3308	slave2	3309

主节点配置文件

• master1

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
	
# 主服务器唯一ID
server-id=1
# 启用二进制日志
log-bin=mysql-bin
# 设置不要复制的数据库(可设置多个)
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-ignore-db=performance_schema
binlog-ignore-db=sys
# 设置需要复制的数据库(可设置多个) 
binlog-do-db=test
# 设置logbin格式，默认STATEMENT记录sql语句，ROW：记录行中修改的列,MIXED:智能选择
binlog_format=MIXED

# 自增长字段从那个数开始
auto-increment-offset=1
# 自增长字段每次递增的量
auto-increment-increment=2

# Custom config should go here
!includedir /etc/mysql/conf.d/

• master2

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
	
# 主服务器唯一ID
server-id=2
#启用二进制日志
log-bin=mysql-bin
# 设置不要复制的数据库(可设置多个)
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-ignore-db=performance_schema
binlog-ignore-db=sys
# 设置需要复制的数据库(可设置多个)  
binlog-do-db=test
# 设置logbin格式，默认STATEMENT记录sql语句，ROW：记录行中修改的列,MIXED:智能选择
binlog_format=MIXED
# 自增长字段从那个数开始
auto-increment-offset=2
# 自增长字段每次递增的量
auto-increment-increment=2
	
# Custom config should go here
!includedir /etc/mysql/conf.d/

注意点
binlog-do-db：指定mysql的binlog日志记录哪个db
Replicate_Do_DB：参数是在slave上配置，指定slave要复制哪个库
在master上设置binlog_do_db弊端：
1、过滤操作带来的负载都在master上
2、无法做基于时间点的复制（利用binlog）。

从节点配置文件

• slave1

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
server-id=3
relay-log=mysql-relay
	
# Custom config should go here
!includedir /etc/mysql/conf.d/

• slave2

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
server-id=4
relay-log=mysql-relay
	
# Custom config should go here
!includedir /etc/mysql/conf.d/

docker启动mysql容器

docker及docker-compose基础

• master1

docker run --name mysql-master1 -p 3306:3306 --privileged=true \
-v /docker/mysql/master1/conf/my.cnf:/etc/mysql/my.cnf \
-v /docker/mysql/master1/logs:/var/log/mysql \
-v /docker/mysql/master1/data:/var/lib/mysql\
-e MYSQL_ROOT_PASSWORD=root -d mysql:latest --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci --default-authentication-plugin=mysql_native_password

• slave1

docker run --name mysql-slave1 -p 3307:3306 --privileged=true \
-v /docker/mysql/slave1/conf/my.cnf:/etc/mysql/my.cnf \
-v /docker/mysql/slave1/logs:/var/log/mysql \
-v /docker/mysql/slave1/data:/var/lib/mysql \
-e MYSQL_ROOT_PASSWORD=root -d mysql:latest --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci --default-authentication-plugin=mysql_native_password

• master2

docker run --name mysql-master2 -p 3308:3306 --privileged=true  \
-v /docker/mysql/master2/conf/my.cnf:/etc/mysql/my.cnf \
-v /docker/mysql/master2/logs:/var/log/mysql \
-v /docker/mysql/master2/data:/var/lib/mysql \
-e MYSQL_ROOT_PASSWORD=root -d mysql:latest --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci --default-authentication-plugin=mysql_native_password

• slave2

docker run --name mysql-slave2 -p 3309:3306 --privileged=true \
-v /docker/mysql/slave2/conf/my.cnf:/etc/mysql/my.cnf \
-v /docker/mysql/slave2/logs:/var/log/mysql \
-v /docker/mysql/slave2/data:/var/lib/mysql \
-e MYSQL_ROOT_PASSWORD=root -d mysql:latest --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci --default-authentication-plugin=mysql_native_password

docker-compose编排文件启动容器

[root@localhost mysql]# cat docker-compose.yml 
version: '3'
services:
  mysql-master1: 
    image: mysql:latest
    container_name: mysql-master1
    restart: always
    privileged: true
    ports:
      - "3306:3306"
    environment: 
      - MYSQL_ROOT_PASSWORD=root
      - character-set-server=utf8mb4
      - collation-server=utf8mb4_unicode_ci
      - default-authentication-plugin=mysql_native_password
    volumes:
      - /docker/mysql/master1/conf/my.cnf:/etc/mysql/my.cnf
      - /docker/mysql/master1/logs:/var/log/mysql
      - /docker/mysql/master1/data:/var/lib/mysql
  mysql-master2: 
    image: mysql:latest
    container_name: mysql-master2
    restart: always
    privileged: true
    ports:
      - "3308:3306"
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - character-set-server=utf8mb4
      - collation-server=utf8mb4_unicode_ci
      - default-authentication-plugin=mysql_native_password
    volumes:
      - /docker/mysql/master2/conf/my.cnf:/etc/mysql/my.cnf
      - /docker/mysql/master2/logs:/var/log/mysql
      - /docker/mysql/master2/data:/var/lib/mysql
  mysql-slave1: 
    image: mysql:latest
    container_name: mysql-slave1
    restart: always
    privileged: true
    ports:
      - "3307:3306"
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - character-set-server=utf8mb4
      - collation-server=utf8mb4_unicode_ci
      - default-authentication-plugin=mysql_native_password
    volumes:
      - /docker/mysql/slave1/conf/my.cnf:/etc/mysql/my.cnf
      - /docker/mysql/slave1/logs:/var/log/mysql
      - /docker/mysql/slave1/data:/var/lib/mysql
  mysql-slave2: 
    image: mysql:latest
    container_name: mysql-slave2
    restart: always
    privileged: true
    ports:
      - "3309:3306"
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - character-set-server=utf8mb4
      - collation-server=utf8mb4_unicode_ci
      - default-authentication-plugin=mysql_native_password
    volumes:
      - /docker/mysql/slave2/conf/my.cnf:/etc/mysql/my.cnf
      - /docker/mysql/slave2/logs:/var/log/mysql
      - /docker/mysql/slave2/data:/var/lib/mysql

主节点创建用于复制操作的用户并授权

• master1

# 进入mysql-master1容器
[root@localhost mysql]# docker exec -it mysql-master1 bash
# 登录mysql
root@2929f5c20467:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.
# 创建用户
mysql> create user 'slave'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
Query OK, 0 rows affected (0.03 sec)
# 授权
mysql> grant replication slave on *.* to 'slave'@'%';
Query OK, 0 rows affected (0.00 sec)
# 刷新
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
# 验证用户创建成功
mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select User,Host,authentication_string from user;
+------------------+-----------+------------------------------------------------------------------------+
| User             | Host      | authentication_string                                                  |
+------------------+-----------+------------------------------------------------------------------------+
| root             | %         | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B                              |
| slave            | %         | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9                              |
| mysql.infoschema | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| mysql.session    | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| mysql.sys        | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| root             | localhost | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B                              |
+------------------+-----------+------------------------------------------------------------------------+
6 rows in set (0.00 sec)

mysql> exit
Bye
root@2929f5c20467:/# exit
exit

• master2

[root@localhost mysql]# docker exec -it mysql-master2 bash
root@7b32e9b09f14:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.

mysql> create user 'slave'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
Query OK, 0 rows affected (0.01 sec)

mysql> grant replication slave on *.* to 'slave'@'%';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select User,Host,authentication_string from user;
+------------------+-----------+------------------------------------------------------------------------+
| User             | Host      | authentication_string                                                  |
+------------------+-----------+------------------------------------------------------------------------+
| root             | %         | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B                              |
| slave            | %         | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9                              |
| mysql.infoschema | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| mysql.session    | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| mysql.sys        | localhost | $A$005$THISISACOMBINATIONOFINVALIDSALTANDPASSWORDTHATMUSTNEVERBRBEUSED |
| root             | localhost | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B                              |
+------------------+-----------+------------------------------------------------------------------------+
6 rows in set (0.00 sec)

查看master状态

记录File和Position

show master status;

• master1

mysql> show master status;
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB                                | Executed_Gtid_Set |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| mysql-bin.000010 |      156 | test         | mysql,information_schema,performance_schema,sys |                   |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
1 row in set (0.01 sec)
mysql> exit
Bye
root@8d669cfbb9e4:/# exit
exit

• master2

mysql> show master status;
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB                                | Executed_Gtid_Set |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| mysql-bin.000009 |      346 | test         | mysql,information_schema,performance_schema,sys |                   |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
1 row in set (0.00 sec)

1 row in set (0.00 sec)
mysql> exit
Bye
root@8d669cfbb9e4:/# exit
exit

从机配置需要复制的主机

• slave1

[root@localhost mysql]# docker exec -it mysql-slave1 bash
root@79800b1e74f1:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.

mysql> CHANGE MASTER TO \
    -> MASTER_HOST='192.168.1.234',\
    -> MASTER_PORT=3306,\
    -> MASTER_USER='slave',\
    -> MASTER_PASSWORD='123456',\
    -> MASTER_LOG_FILE='mysql-bin.000010',\
    -> MASTER_LOG_POS=156;
Query OK, 0 rows affected, 2 warnings (0.10 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.234
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000010
          Read_Master_Log_Pos: 156
               Relay_Log_File: mysql-relay.000002
                Relay_Log_Pos: 324
        Relay_Master_Log_File: mysql-bin.000010
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 156
              Relay_Log_Space: 529
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 1096c5ee-ac77-11ea-b30b-0242ac110002
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 
1 row in set (0.00 sec)

• slave2

[root@localhost mysql]# docker exec -it mysql-slave2 bash
root@ebdbb5a83652:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.

mysql> CHANGE MASTER TO \
    -> MASTER_HOST='192.168.1.234',\
    -> MASTER_PORT=3308,\
    -> MASTER_USER='slave',\
    -> MASTER_PASSWORD='123456',\
    -> MASTER_LOG_FILE='mysql-bin.000009',\
    -> MASTER_LOG_POS=346;
Query OK, 0 rows affected, 2 warnings (0.04 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.234
                  Master_User: slave
                  Master_Port: 3308
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000009
          Read_Master_Log_Pos: 346
               Relay_Log_File: mysql-relay.000002
                Relay_Log_Pos: 324
        Relay_Master_Log_File: mysql-bin.000009
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 346
              Relay_Log_Space: 529
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 2
                  Master_UUID: 59e8cd49-ac79-11ea-b7e3-0242ac160003
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 
1 row in set (0.00 sec)

注意点

• Slave_IO_Running和Slave_SQL_Running：必须都为yes；
• Slave_IO_Running表示slave与主机的IO通讯 I/O thread，不为yes时可能的原因：
  1.网络不通
  2.账户密码错误
  3.防火墙
  4.mysql配置文件问题(server-id重复)
  5.连接服务器时语法
  6.主服务器mysql权限
• Slave_SQL_Running表示slave从中继日志中读取二进制日志SQL Thread，不为yes时可能的原因：
  1.在从机上进行了写操作（非双机热备情况下）。
  2.slave机器重启，事务回滚。
  3.各种原因导致的数据不同步。
  解决方案1:因事务的原因导致的sql进程停止。

mysql> stop slave;
mysql> set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
mysql> start slave;

解决方案2:因binlog不一致导致的不同步。
从机重新配置主从同步。

测试主从复制成功

在master1上创建test数据库(因为maser1和master2设置的binlog-to-db=test)，创建表并插入一条记录，然后登录slave1上查看数据是否同步。

[root@localhost mysql]# docker exec -it mysql-master1 bash
root@95f938b82a6c:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 16
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.

mysql> create database test;
Query OK, 1 row affected (0.01 sec)

mysql> use test;
Database changed

mysql> create table user (user_name VARCHAR(32));
Query OK, 0 rows affected (0.03 sec)

mysql> insert into user(user_name) value('admin');
Query OK, 1 row affected (0.01 sec)

mysql> exit
Bye
root@95f938b82a6c:/# exit
exit
[root@localhost mysql]# docker exec -it mysql-slave1 bash
root@79800b1e74f1:/# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 8.0.20 MySQL Community Server - GPL

Copyright (c) 2000, 2020, 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.

mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select * from user;
+-----------+
| user_name |
+-----------+
| admin     |
+-----------+
1 row in set (0.00 sec)