Ruby gem mysql2 install failing

When I try to install the mysql2 gem, it fails with no apparent errors. Does anyone know what to do to work around this so mysql2 installs?

$ sudo gem install mysql2
Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
	ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
checking for rb_thread_blocking_region()... no
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... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lmygcc... no
checking for mysql_query() in -lmysqlclient... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
	--with-opt-dir
	--without-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
	--with-mysql-config
	--without-mysql-config
	--with-mysql-dir
	--without-mysql-dir
	--with-mysql-include
	--without-mysql-include=${mysql-dir}/include
	--with-mysql-lib
	--without-mysql-lib=${mysql-dir}/lib
	--with-mysqlclientlib
	--without-mysqlclientlib
	--with-mlib
	--without-mlib
	--with-mysqlclientlib
	--without-mysqlclientlib
	--with-zlib
	--without-zlib
	--with-mysqlclientlib
	--without-mysqlclientlib
	--with-socketlib
	--without-socketlib
	--with-mysqlclientlib
	--without-mysqlclientlib
	--with-nsllib
	--without-nsllib
	--with-mysqlclientlib
	--without-mysqlclientlib
	--with-mygcclib
	--without-mygcclib
	--with-mysqlclientlib
	--without-mysqlclientlib


Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/ext/mysql2/gem_make.out

Ubuntu:

sudo apt-get install libmysqlclient-dev  #(mysql development headers)
sudo gem install mysql2 -- --with-mysql-dir=/etc/mysql/

That's it!

Result:

Building native extensions. This could take a while...
Successfully installed mysql2-0.2.6
1 gem installed
Installing ri documentation for mysql2-0.2.6...
Enclosing class/module 'mMysql2' for class Result not known
Enclosing class/module 'mMysql2' for class Client not known
Installing RDoc documentation for mysql2-0.2.6...
Enclosing class/module 'mMysql2' for class Result not known
Enclosing class/module 'mMysql2' for class Client not known

You need the MySQL development headers for mysql2 to properly compile. This is needed, because much of the functionality is written in C and subsequently linked against MySQL.

A solution is to either point the gem installer to your mysql install folder explicitly like so

gem install mysql2 -- --with-mysql-dir=/usr/local/mysql
# or where ever you installed your mysql server to

or by installing a mysql server to a known location (e.g. by using homebrew.) and then installing the gem

# install the mysql server locally
brew install mysql
# install the gem
gem install mysql2

Both approaches require you to have XCode installed to have the required GCC compiler.

You have to have 64-bit MySQL installed on your machine, plus the build tools you get when you install xcode.

With Brew and MySQL installed, I used the following to install the mysql2 gem

gem install mysql2 -- --with-mysql-config=/usr/local/Cellar/mysql/5.5.10/bin/mysql_config

If you're using Bundler, you can tell bundler about this with command:

bundle config build.mysql2 --with-mysql-config=/usr/local//Cellar/mysql/5.5.10/bin/mysql_config

As documented here: http://gembundler.com/man/bundle-config.1.html

on Mac OSX Moutain Lion, below command worked for me:

gem install mysql2 -- --srcdir=/usr/local/mysql/include

Ubuntu 15.04:

sudo apt-get install libmysqlclient-dev
sudo gem install mysql2

Ubuntu-16.04:

sudo apt-get install ruby-mysql2
sudo gem install mysql2

Output:

Building native extensions.  This could take a while...
Successfully installed mysql2-0.3.19
Parsing documentation for mysql2-0.3.19
Installing ri documentation for mysql2-0.3.19
Done installing documentation for mysql2 after 0 seconds
1 gem installed

You might want to check this thread at the MySQL web site: http://forums.mysql.com/read.php?116,178217,178217, particularly the answer by Scott Derrick: http://forums.mysql.com/read.php?116,178217,189357#msg-189357

To be more specific, try using

sudo gem install mysql2 -- --with-mysql-dir=/usr/local/mysql

Hope that helps.

I dug through 2 days worth of the internet and Stack Overflow, and it wasn't until I found this link and then starting working through this ticket for mysql2 that I actually resolved the issue.

With my setup (as explained in the ticket), the compiler switches of -Wno-null-conversion -Wno-unused-private-field would break and give me an error that wasn't exactly correct, which was:

mysql.h is missing. please check your installation of mysql and try again

I solved this by being specific on where are the directories, no need to reinstall anything, with brew or macports or whatever, just by specifying where are the things (only one thing: the ruby on my mac was installed with rvm, I'm not using the default one that comes with os x):

adding to your gem install mysql2 the flags below

• --srcdir="..." - the includes
• --with-mysql-dir="..." - the mysql directory
• --with-mysql-config="..." - the mysql_config file

like this gem install mysql2 --srcdir=/usr/local/mysql/include/ --with-mysql-dir=/usr/local/mysql --with-mysql-config=/usr/local/mysql/bin/mysql_config

In Centos 6.x (7 should work) with SCL (software collection) rh-mysql:

scl enable rh-mysql56 bash
gem install mysql2 -v '0.4.5' -- --with-mysql-include=/opt/rh/rh-mysql56/root/usr/include --with-mysql-lib=/opt/rh/rh-mysql56/root/usr/lib64

I guess that if you type rvm use [email protected] --create in you directory then bundle install it works.