Getting the mysql gem installed on Ubuntu

If you’re like me, you’ve gotten the ‘MySQL lost connection’ errors when running rails apps on Ubunutu. And if you’ve tried to apply the common fix – installing the mysql gem – you might not have been able to and have seen an error such as:

ERROR: While executing gem … (Gem::Installer::ExtensionBuildError)
ERROR: Failed to build gem native extension.

The problem is that you need the MySQL development headers in order to get the ruby gem to compile…sooo, you need to install this first (gem install mysql-dev won’t work):

apt-get install libmysqlclient12-dev

Then run:

gem install mysql

Select the right gem and you should be all set.

UPDATE:

if you see the error:

ruby extconf.rb install mysql
checking for mysql_query() in -lmysqlclient… no
checking for main() in -lm… yes
checking for mysql_query() in -lmysqlclient… no
checking for main() in -lz… yes
checking for mysql_query() in -lmysqlclient… no
checking for main() in -lsocket… no
checking for mysql_query() in -lmysqlclient… no
checking for main() in -lnsl… yes
checking for mysql_query() in -lmysqlclient… no
*** extconf.rb failed ***

try:

sudo gem install mysql — –with-mysql-config