MySQL多实例讲解
mysql多实例,每个MySQL多实例讲解实例的datadir,pid,port,socket应该是不同的,在Unix中,在你启动客户端之前,设置MYSQL_UNIX_P
mysql多实例,每个实例的datadir,pid,port,socket应该是不同的
一、基础,很重要
每个实例应该在自己的datadir下配置my.cnf文件。
首先说下配置文件的查找顺序
第一搜,首先读取/etc/my.cnf
第二搜,$datadir/my.cnf,在data目录下寻找此配置文件,每个实例应该在自己的datadir下配置my.cnf文件。
第三搜,defaultfile=/path/my.cnf 通常写在命令行上,mysqld_safe defaultfile=/tmp/my.cnf &等执行。
第四搜,~/my.cnf 当前用户下的配置文件。
二、为各个实例配置datadir(例子中利用默认实例数据)
停掉mysql默认的服务(防止出现损坏默认实例数据库的情况):service mysql
stop
复制datadir
[root@localhost lib]# cp -r mysql /var/lib/mysql_3301
[root@localhost lib]# cp -r mysql /var/lib/mysql_3302
把mysql设置为owner
[root@localhost lib]# chown -R mysql.mysql mysql_3301
[root@localhost lib]# chown -R mysql.mysql mysql_3302
把mysql设置为文件夹内文件的owner
[root@localhost lib]# cd mysql_3301
[root@localhost mysql_3301]# chown -R mysql.mysql *
[root@localhost mysql_3301]# cd ../mysql_3302
[root@localhost mysql_3302]# chown -R mysql.mysql *
注释:
开始失败的原因在于mysql_3301与mysql_3302文件夹下的文件没有赋权于mysql用
户,,导致错误
cd mysql_3301
chown -R mysql.mysql *
cd ../mysql_3302
chown -R mysql.mysql *
三、配置文件选项:
[root@localhost mysql_3302]# cd /usr/local
[root@localhost local]# vi my_multi.cnf
[mysqld_multi]
mysqld = /usr/bin/mysqld_safe
mysqladmin = /usr/bin/mysqladmin
user = root
[mysqld1]
socket = /tmp/mysql_3301.sock
port = 3301
pid-file = /var/lib/mysql_3301/hostname.pid
datadir = /var/lib/mysql_3301/
log = /var/lib/mysql_3301/hostname.log
user = mysql
[mysqld2]
socket = /tmp/mysql_3302.sock
port = 3302
pid-file = /var/lib/mysql_3302/hostname.pid
datadir = /var/lib/mysql_3302/
log = /var/lib/mysql_3302/hostname.log
user = mysql

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



Go language is an efficient, concise and easy-to-learn programming language. It is favored by developers because of its advantages in concurrent programming and network programming. In actual development, database operations are an indispensable part. This article will introduce how to use Go language to implement database addition, deletion, modification and query operations. In Go language, we usually use third-party libraries to operate databases, such as commonly used sql packages, gorm, etc. Here we take the sql package as an example to introduce how to implement the addition, deletion, modification and query operations of the database. Assume we are using a MySQL database.

Apple's latest releases of iOS18, iPadOS18 and macOS Sequoia systems have added an important feature to the Photos application, designed to help users easily recover photos and videos lost or damaged due to various reasons. The new feature introduces an album called "Recovered" in the Tools section of the Photos app that will automatically appear when a user has pictures or videos on their device that are not part of their photo library. The emergence of the "Recovered" album provides a solution for photos and videos lost due to database corruption, the camera application not saving to the photo library correctly, or a third-party application managing the photo library. Users only need a few simple steps

Hibernate polymorphic mapping can map inherited classes to the database and provides the following mapping types: joined-subclass: Create a separate table for the subclass, including all columns of the parent class. table-per-class: Create a separate table for subclasses, containing only subclass-specific columns. union-subclass: similar to joined-subclass, but the parent class table unions all subclass columns.

How to use MySQLi to establish a database connection in PHP: Include MySQLi extension (require_once) Create connection function (functionconnect_to_db) Call connection function ($conn=connect_to_db()) Execute query ($result=$conn->query()) Close connection ( $conn->close())

To handle database connection errors in PHP, you can use the following steps: Use mysqli_connect_errno() to obtain the error code. Use mysqli_connect_error() to get the error message. By capturing and logging these error messages, database connection issues can be easily identified and resolved, ensuring the smooth running of your application.

HTML cannot read the database directly, but it can be achieved through JavaScript and AJAX. The steps include establishing a database connection, sending a query, processing the response, and updating the page. This article provides a practical example of using JavaScript, AJAX and PHP to read data from a MySQL database, showing how to dynamically display query results in an HTML page. This example uses XMLHttpRequest to establish a database connection, send a query and process the response, thereby filling data into page elements and realizing the function of HTML reading the database.

PHP is a back-end programming language widely used in website development. It has powerful database operation functions and is often used to interact with databases such as MySQL. However, due to the complexity of Chinese character encoding, problems often arise when dealing with Chinese garbled characters in the database. This article will introduce the skills and practices of PHP in handling Chinese garbled characters in databases, including common causes of garbled characters, solutions and specific code examples. Common reasons for garbled characters are incorrect database character set settings: the correct character set needs to be selected when creating the database, such as utf8 or u

Through the Go standard library database/sql package, you can connect to remote databases such as MySQL, PostgreSQL or SQLite: create a connection string containing database connection information. Use the sql.Open() function to open a database connection. Perform database operations such as SQL queries and insert operations. Use defer to close the database connection to release resources.
