Memcached启动脚本
# vim /etc/init.d/memcached
#!/bin/bash #======================================================================================= # chkconfig: - 80 12 # description: Distributed memory caching daemon # processname: memcached #======================================================================================= IPADDR=`/sbin/ifconfig eth1 | awk -F ':' '/inet addr/{print $2}' | sed 's/[a-zA-Z ]//g'` PORT="11211" USER="root" SIZE="2048" CONNNUM="51200" PIDFILE="/var/run/memcached.pid" BINFILE="/usr/local/memcached/bin/memcached" LOCKFILE="/var/lock/subsys/memcached" RETVAL=0 start() { echo -n $"Starting memcached......" $BINFILE -d -l $IPADDR -p $PORT -u $USER -m $SIZE -c $CONNNUM -P $PIDFILE RETVAL=$? echo [ $RETVAL -eq 0 ] && touch $LOCKFILE return $RETVAL } stop() { echo -n $"Shutting down memcached......" /sbin/killproc $BINFILE RETVAL=$? echo [ $RETVAL -eq 0 ] && rm -f $LOCKFILE return $RETVAL } restart() { stop sleep 1 start } reload() { echo -n $"Reloading memcached......" /sbin/killproc $BINFILE -HUP RETVAL=$? echo return $RETVAL } case "$1" in start) start ;; stop) stop ;; restart) restart ;; condrestart) [ -e $LOCKFILE ] && restart RETVAL=$? ;; reload) reload ;; status) status $prog RETVAL=$? ;; *) echo "Usage: $0 {start|stop|restart|condrestart|status}" RETVAL=1 esac
exit $RETVAL # chmod +x /etc/init.d/memcached # chkconfig --add memcached # chkconfig --level 235 memcached on # service memcached start
binlog 自动清理脚本
# vim /data/scripts/delete_mysql_binlog.sh
#!/bin/bash #======================================================================================= # 用于删除 MySQL Master 端已经同步完的 binlog【需在 Master 端运行】,以减少磁盘空间 # 每天凌晨 5:30 分运行一次 # # 注:需在 Slave 端添加允许 Master 端访问的帐号【帐号:check_binlog,密码:binlog_2356】 # 运行于 MySQL Master 端【目前只用于一主一从的同步模式,对于多从的情况暂时未考虑】 #======================================================================================= PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin ## Slave端连接信息 SLAVE_ADDR="XXX.XXX.XXX.XXX" SLAVE_USER="check_binlog" SLAVE_PWD="binlog_2356" LOGFILE="/data/logs/db_sync_info.log" PINGFILE="/tmp/mysqlping.log" ## MySQL状态信息查看命令 SQLCMD="show slave status" #======================================================================================= ## 检查MySQL是否已经运行 if [[ `ps aux | grep mysql[d] | wc -l` -eq 0 ]]; then echo The MySQL is not running at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 测试Slave端的连通性 nohup mysqladmin -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} ping > ${PINGFILE} retval=`grep "^error" ${PINGFILE}` rm -f ${PINGFILE} if [[ "${retval}X" != "X" ]]; then echo The MySQL Slave can not be connected at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 检查是否合法的Slave MASTER_ADDR=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "${SQLCMD}\G;" | awk '$1=="Master_Host:" {print $2}'` LOCAL_ADDR=`/sbin/ifconfig eth1 | awk -F ':' '/inet addr/{print $2}' | sed 's/[a-zA-Z ]//g'` if [[ "${MASTER_ADDR}" != "${LOCAL_ADDR}" ]]; then echo The MySQL Slave is not lawful at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 获得Slave端信息,以此来确定是否处于正常同步的情况 IO_STATUS=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "${SQLCMD}\G;" | awk '$1=="Slave_IO_Running:" {print $2}'` SQL_STATUS=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "${SQLCMD}\G;" | awk '$1=="Slave_SQL_Running:" {print $2}'` if [[ "${IO_STATUS}" != "Yes" || "${SQL_STATUS}" != "Yes" ]]; then echo The MySQL Replication is not synchronous at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 再做一次判断,以保证数据同步绝对正常【创建测试数据】 mysql -uroot -e "create database if not exists mytestdb;" sleep 3 retval=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "show databases;" | grep mytestdb` mysql -uroot -e "drop database if exists mytestdb;" if [[ "${retval}X" = "X" ]]; then echo The MySQL Replication is not synchronous at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 在已经同步的情况,还需要判断当前同步的binlog,以此来确定哪些已经是过期的binlog SLAVE_BINLOG1=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "${SQLCMD}\G;" | awk '$1=="Master_Log_File:" {print $2}'` SLAVE_BINLOG2=`mysql -h${SLAVE_ADDR} -u${SLAVE_USER} -p${SLAVE_PWD} -e "${SQLCMD}\G;" | awk '$1=="Relay_Master_Log_File:" {print $2}'` ## 获得Master端,当前的binlog文件以及binlog路径 MASTER_BINLOG=`mysql -uroot -e "show master status;" | grep -v '^+' | tail -1 | awk '{print $1}'` ## 主从端已经同步到相同的binlog if [[ "${SLAVE_BINLOG1}" = "${SLAVE_BINLOG2}" && "${SLAVE_BINLOG1}" = "${MASTER_BINLOG}" ]]; then CURR_BINLOG="${MASTER_BINLOG}" ## 主从端已经同步,但从端的binlog还没有追赶到主端最新的binlog elif [[ "${SLAVE_BINLOG1}" = "${SLAVE_BINLOG2}" && "${SLAVE_BINLOG1}" != "${MASTER_BINLOG}" ]]; then CURR_BINLOG="${SLAVE_BINLOG1}" ## 主从端已经同步,主从端的binlog一致,但relaylog还不一致 elif [[ "${SLAVE_BINLOG1}" != "${SLAVE_BINLOG2}" && "${SLAVE_BINLOG1}" = "${MASTER_BINLOG}" ]]; then CURR_BINLOG="${SLAVE_BINLOG2}" else echo Has noknown error at:`date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi mysql -uroot -e "purge binary logs to '${CURR_BINLOG}';" if [[ $? -eq 0 ]]; then echo Clear MySQL binlog is ok at: `date +%F" "%H-%M-%S` >> ${LOGFILE} fi
# crontab -e 30 05 * * * /data/scripts/delete_mysql_binlog.sh >/dev/null 2>&1
修复MySQL主从同步
#!/bin/sh PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin LOGFILE=/data/repair_mysql_sync_`date +%F`.log SQLCMD1="show slave status" ## 查看MySQL是否已启动 if [[ `ps aux | grep mysqld | grep -v grep`"X" = "X" ]]; then echo The MySQL is not running at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 获得MySQL从端Relay binlog的路径 retval=`grep "^relay-log" /etc/my.cnf | grep -v relay-log- | grep '/'` if [[ "${retval}" = "X" ]]; then RELAY_BINLOG_PATH=`ps aux | grep -w mysqld | grep -v grep | awk '{print $13}' | awk -F '=' '{print $2}'` else RELAY_BINLOG_PATH=`dirname $(echo ${retval} | awk -F '=' '{print $2}')` fi ## 查找master.info文件,用于定位Binlog信息 MASTER_FILE=`ps aux | grep -w mysqld | grep -v grep | awk '{print $13}' | awk -F '=' '{print $2}'`/master.info if [[ ! -e ${MASTER_FILE} ]]; then echo This Server is not MySQL Slave at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 1 fi ## 获得当前的同步状态 IO_STATUS=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Slave_IO_Running:" {print $2}'` SQL_STATUS=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Slave_SQL_Running:" {print $2}'` if [[ "${IO_STATUS}" = "Yes" && "${SQL_STATUS}" = "Yes" ]]; then echo Now, The MySQL Replication is synchronous at: `date +%F" "%H-%M-%S` >> ${LOGFILE} exit 0 fi ## 从master.info文件中,获得MySQL主端的同步信息 REPLI_INFO=`sed '/^$/d' ${MASTER_FILE} | tail +2 | head -5` REPLI_BINLOG_FILE=`echo ${REPLI_INFO} | awk '{print $1}'` REPLI_IPADDR=`echo ${REPLI_INFO} | awk '{print $3}'` REPLI_USER=`echo ${REPLI_INFO} | awk '{print $4}'` REPLI_PWD=`echo ${REPLI_INFO} | awk '{print $5}'` ## 删除无用的Relay binlog rm -rf ${RELAY_BINLOG_PATH}/*-relay-bin.* ## 直接从0位置开始同步 SQLCMD2="change master to master_host='${REPLI_IPADDR}', master_user='${REPLI_USER}', master_password='${REPLI_PWD}'," SQLCMD2="${SQLCMD2} master_log_file='${REPLI_BINLOG_FILE}', master_log_pos=0" mysql -uroot -e "stop slave;" mysql -uroot -e "${SQLCMD2};" mysql -uroot -e "start slave;" ## 如果同步的过程中,出现重复记录导致同步失败,就跳过 while true do sleep 2 IO_STATUS=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Slave_IO_Running:" {print $2}'` SQL_STATUS=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Slave_SQL_Running:" {print $2}'` BEHIND_STATUS=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Seconds_Behind_Master:" {print $2}'` SLAVE_BINLOG1=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Master_Log_File:" {print $2}'` SLAVE_BINLOG2=`mysql -uroot -e "${SQLCMD1}\G;" | awk '$1=="Relay_Master_Log_File:" {print $2}'` ## 出现错误,就将错误信息记录到日志文件,并跳过错误继续同步 if [[ "${IO_STATUS}" != "Yes" || "${SQL_STATUS}" != "Yes" ]]; then ERRORINFO=`mysql -uroot -e "${SQLCMD1}\G;" | awk -F ': ' '$1=="Last_Error" {print $2}'` echo "The MySQL synchronous error information: ${ERRORINFO}" >> ${LOGFILE} mysql -uroot -e "stop slave;" mysql -uroot -e "set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;" mysql -uroot -e "start slave;" ## 已完成同步,就正常退出 elif [[ "${IO_STATUS}" = "Yes" && "${SQL_STATUS}" = "Yes" && "${SLAVE_BINLOG1}" = "${SLAVE_BINLOG2}" && ${BEHIND_STATUS} -eq 0 ]]; then echo The MySQL synchronous is ok at: `date +%F" "%H-%M-%S` >> ${LOGFILE} break fi done

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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