ubuntu 升级到12.04引起的mysql错误
ubuntu12.04中将mysql升级到5.5.22导致原先的mysql加载失败
解决方法：
1.完全卸载原先的mysql
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sudo apt-get remove mysql-serversudo apt-get autoremove --purge mysql-serversudo apt-get remove mysql-common(这步比较重要)dpkg -l | grep ^rc | awk '{print $2}' | sudo xargs dpkg -P?2.重新安装mysql（安装前最好重启）
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sudo apt-get install mysql-serversudo apt-get install mysql-workbench(原先的client无法使用)
可使用以下命令检查是否安装成功
sudo netstat -tap | grep mysql
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3原先gem中的mysql2需要重新编译安装
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gem uninstall mysql2gem install mysql2?
4.安装mysql2时可能出现以下错误
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Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension./homexxx/.rbenv/versions/1.9.3-p125/bin/ruby extconf.rb checking for rb_thread_blocking_region()... yeschecking for rb_wait_for_single_fd()... yeschecking for mysql_query() in -lmysqlclient... nochecking for main() in -lm... yeschecking for mysql_query() in -lmysqlclient... nochecking for main() in -lz... yeschecking for mysql_query() in -lmysqlclient... nochecking for main() in -lsocket... nochecking for mysql_query() in -lmysqlclient... nochecking for main() in -lnsl... yeschecking for mysql_query() in -lmysqlclient... nochecking for main() in -lmygcc... nochecking for mysql_query() in -lmysqlclient... no*** extconf.rb failed ***Could not create Makefile due to some reason, probably lack ofnecessary libraries and/or headers. Check the mkmf.log file for moredetails. You may need configuration options.
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sudo apt-get install libmysql-rubysudo apt-get install libmysqlclient-devgem install mysql