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1、mysql安装
#usedel mysql
#groupdel mysql
#groupadd mysql
#useradd -g mysql mysql
#tar -zxvf mysql-5.1.55.tar.gz
#cd mysql-5.1.55
#./configure /
#>—prefix=/program/mysql / //安装路径
#>—localstatedir=/var/lib/mysql / //数据库文件存放路径
#>—with-comment=Source /
#>—with-server-suffix=-Community /
#>—with-mysqld-user=mysql /
#>—without-debug /
#>—with-big-tables /
#>—with-charset=utf8/
#>—with-collation=utf8_unicode_ci /
#>—with-extra-charsets=all /
#>—with-pthread /
#>—enable-static /
#>—enable-thread-safe-client /
#>—with-client-ldflags=-all-static /
#>—with-mysqld-ldflags=-all-static /
#>—enable-assembler /
#>—without-innodb /
#>—with-innodb /
#>—without-isam /
#>—without-ndb-debug /
#>—with-unix-socket-path=/var/lib/mysql/mysql.sock
#make && make install
#cp ./support-files/my-medium.cnf /etc/my.cnf
#/usr/local/mysql/bin/mysql_install_db —user=mysql
#chown mysql:mysql -R /usr/local/mysql
#chgrp -R mysql /usr/local/mysql
#/usr/local/mysql/bin/mysqld_safe —user=mysql &
#chmod +x ./support-files/mysql.server
#cp ./support-files/mysql.server /etc/init.d/mysqld
#chkconfig –add mysqld
#chkconfig –level 2345 mysqld on
#service mysqld restart
#/usr/local/mysql/bin/mysqladmin -uroot password “new_pass” //修改root用户密码
#netstat -nplt |grep mysql //查看mysql监听端口的信息
#ps -aux |grep mysql //查看mysql运行的进程信息
2、mysql密码恢复
#service mysqld stop
#killall -TERM mysqld
#/usr/local/mysql/bin/safe_mysqld —skip-grant-tables &
#/usr/local/mysql/bin/mysq/mysql
>use msyqlmysql
>upadate user set password=password(“new_pass”) where user=”root”;
>flush privileges;
>exit
#service mysqld start#mysql -uroot -p //如果提示输入密码表明破解密码成功完成;
3、mysql环境变量的设置:
第一种:
#export PATH=$PATH:/usr/local/mysql/bin/
#export //查看环境变量
第二种:
#vi /etc/profileexport PATH=”$PATH:文件路径” //通过配置文件修改环境变量(需要注销系统才能生效)
#env //查看环境变量
第三种:
#vi /root/.bashrcexport PATH=”$PATH:文件路径” //修改root用户的环境变量(需要注销系统才能生效)
#echo $PATH //查看环境变量
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To optimize MySQL slow query, slowquerylog and performance_schema need to be used: 1. Enable slowquerylog and set thresholds to record slow query; 2. Use performance_schema to analyze query execution details, find out performance bottlenecks and optimize.

MySQL and SQL are essential skills for developers. 1.MySQL is an open source relational database management system, and SQL is the standard language used to manage and operate databases. 2.MySQL supports multiple storage engines through efficient data storage and retrieval functions, and SQL completes complex data operations through simple statements. 3. Examples of usage include basic queries and advanced queries, such as filtering and sorting by condition. 4. Common errors include syntax errors and performance issues, which can be optimized by checking SQL statements and using EXPLAIN commands. 5. Performance optimization techniques include using indexes, avoiding full table scanning, optimizing JOIN operations and improving code readability.

MySQL asynchronous master-slave replication enables data synchronization through binlog, improving read performance and high availability. 1) The master server record changes to binlog; 2) The slave server reads binlog through I/O threads; 3) The server SQL thread applies binlog to synchronize data.

MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.

The installation and basic operations of MySQL include: 1. Download and install MySQL, set the root user password; 2. Use SQL commands to create databases and tables, such as CREATEDATABASE and CREATETABLE; 3. Execute CRUD operations, use INSERT, SELECT, UPDATE, DELETE commands; 4. Create indexes and stored procedures to optimize performance and implement complex logic. With these steps, you can build and manage MySQL databases from scratch.

InnoDBBufferPool improves the performance of MySQL databases by loading data and index pages into memory. 1) The data page is loaded into the BufferPool to reduce disk I/O. 2) Dirty pages are marked and refreshed to disk regularly. 3) LRU algorithm management data page elimination. 4) The read-out mechanism loads the possible data pages in advance.

MySQL is suitable for beginners because it is simple to install, powerful and easy to manage data. 1. Simple installation and configuration, suitable for a variety of operating systems. 2. Support basic operations such as creating databases and tables, inserting, querying, updating and deleting data. 3. Provide advanced functions such as JOIN operations and subqueries. 4. Performance can be improved through indexing, query optimization and table partitioning. 5. Support backup, recovery and security measures to ensure data security and consistency.

Full table scanning may be faster in MySQL than using indexes. Specific cases include: 1) the data volume is small; 2) when the query returns a large amount of data; 3) when the index column is not highly selective; 4) when the complex query. By analyzing query plans, optimizing indexes, avoiding over-index and regularly maintaining tables, you can make the best choices in practical applications.


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