Yum升級mysql5.1到5.6
有一些虛擬機、雲主機提供商仍然使用的是老版本的安裝套件。預裝的應用軟件版本很低。
比如 techbrood.com 使用的雲服務器，其中MySQL預裝版本爲老版本5.1.x。而最新的mysql版本在性能、功能、安全性等方面都有了很多的改進。
要從最新版本獲益，你需要把現有系統升級到5.5+（最新的版本是5.7），我保守一點，升級到5.6.37。
有相關測試數據說明從5.1到5.5+，MySQL性能會有明顯的提升，具體的需要自己建立測試環境去實踐下。
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首先更新rpm
從MySQL Yum倉庫下載最新的rpm文件：http://dev.mysql.com/downloads/repo/yum/
（需要Oracle帳號以及填寫一些使用信息，才能進入下載頁面）
我需要下載的是：mysql-community-release-el6-5.noarch.rpm -
安裝這個發佈包
yum localinstall mysql-community-release-el6-5.noarch.rpm
可以通過下面的命令來確認這個倉庫被成功添加：
yum repolist enabled | grep "mysql.-community. -
安裝MySQL服務器
yum install mysql-community-server
新版本的目標文件是/usr/bin/mysql，如果原預裝路徑在/bin下面，則需要進行替換，最好是使用軟鏈接，比如ln -s /usr/bin/mysql /bin/
這樣在需要的時候，可以方便的在不同版本之間進行切換。（有時候需要版本回退來定位問題） - 重啓服務器就可以了
service mysqld restart
確認版本信息：
[root@west195246 bin]# mysql -V
mysql Ver 14.14 Distrib 5.6.20, for Linux (x86_64) using EditLine wrapper
在我進行過的幾次軟件升級之後，總會在 MySQL 的日誌中見到“[ERROR] Missing system table mysql.proxies_priv; please run mysql_upgrade to create it”之類的錯誤。雖然這個錯誤修復起來很簡單，卻不容易引起注意。可以按如下方法修復：
錯誤日誌如下：
[ERROR] InnoDB: auto-extending data file ./ibdata1 is of a different size 640 pages (rounded down to MB) than specified in the .cnf file: initial 16384 pages, max 0 (relevant if non-zero) pages!
2017-09-01 09:15:06 5588 [ERROR] InnoDB: Could not open or create the system tablespace. If you tried to add new data files to the system tablespace, and it failed here, you should now edit innodb_data_file_path in my.cnf back to what it was, and remove the new ibdata files InnoDB created in this failed attempt. InnoDB only wrote those files full of zeros, but did not yet use them in any way. But be careful: do not remove old data files which contain your precious data!
2017-09-01 09:15:06 5588 [ERROR] Plugin 'InnoDB' init function returned error.
2017-09-01 09:15:06 5588 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2017-09-01 09:15:06 5588 [ERROR] Unknown/unsupported storage engine: InnoDB
2017-09-01 09:15:06 5588 [ERROR] Aborting
錯誤提示如下：
[ERROR] Missing system table mysql.proxies_priv; please run mysql_upgrade to create it
[ERROR] Native table 'performance_schema'.'events_waits_current' has the wrong structure
[ERROR] Native table 'performance_schema'.'events_waits_history' has the wrong structure
[ERROR] Native table 'performance_schema'.'events_waits_history_long' has the wrong structure
[ERROR] Native table 'performance_schema'.'setup_consumers' has the wrong structure
[ERROR] Native table 'performance_schema'.'setup_instruments' has the wrong structure
[ERROR] Native table 'performance_schema'.'setup_timers' has the wrong structure
[ERROR] Native table 'performance_schema'.'performance_timers' has the wrong structure
[ERROR] Native table 'performance_schema'.'threads' has the wrong structure
[ERROR] Native table 'performance_schema'.'events_waits_summary_by_thread_by_event_name' has the wrong structure
[ERROR] Native table 'performance_schema'.'events_waits_summary_by_instance' has the wrong structure
[ERROR] Native table 'performance_schema'.'events_waits_summary_global_by_event_name' has the wrong structure
[ERROR] Native table 'performance_schema'.'file_summary_by_event_name' has the wrong structure
[ERROR] Native table 'performance_schema'.'file_summary_by_instance' has the wrong structure
[ERROR] Native table 'performance_schema'.'mutex_instances' has the wrong structure
[ERROR] Native table 'performance_schema'.'rwlock_instances' has the wrong structure
[ERROR] Native table 'performance_schema'.'cond_instances' has the wrong structure
[ERROR] Native table 'performance_schema'.'file_instances' has the wrong structure
[Note] Event Scheduler: Loaded 0 events
[Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.20-log' socket: '/var/lib/mysql/mysql.sock' port: 0
處理方法：
#cd /var/lib/mysql
#rm -rf ib*
#service mysqld restart
需要按照如下的格式在 Linux 的 —— 而不是 MySQL 的 —— 命令提示符下運行：
#mysql_upgrade -u root -p
然後根據提示輸入 mysql 的 root 帳戶密碼，修復過程就可自動運行。此時會有如下形式的提示信息輸出：
mysql_upgrade -u root -p
Enter password:
Looking for 'mysql' as: mysql
Looking for 'mysqlcheck' as: mysqlcheck
Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/lib/mysql/mysql.sock'
Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/lib/mysql/mysql.sock'
wp_commentmeta OK
wp_comments OK
wp_links OK
wp_options OK
wp_postmeta OK
wp_posts OK
wp_term_relationships OK
wp_term_taxonomy OK
wp_terms OK
wp_usermeta OK
wp_users OK
mysql.columns_priv OK
mysql.db OK
mysql.event OK
mysql.func OK
mysql.general_log OK
mysql.help_category OK
mysql.help_keyword OK
mysql.help_relation OK
mysql.help_topic OK
mysql.host OK
mysql.ndb_binlog_index OK
mysql.plugin OK
mysql.proc OK
mysql.procs_priv OK
mysql.servers OK
mysql.slow_log OK
mysql.tables_priv OK
mysql.time_zone OK
mysql.time_zone_leap_second OK
mysql.time_zone_name OK
mysql.time_zone_transition OK
mysql.time_zone_transition_type OK
mysql.user OK
Running 'mysql_fix_privilege_tables'... OK
##service mysqld restart