Error installing mysql2: Failed to build gem native extension

Question

I am having some problems when trying to install mysql2 gem for Rails. When I try to install it by running bundle install or gem install mysq

Answer 1

Got the "You have to install development tools first." error when trying to install the mysql2 gem after upgrading to Mac OS X Mountain Lion. Apparently doing this upgrade removes the command line compilers.

To fix:

• I uninstalled my very old version of Xcode (ran the uninstall script in /Developer/Library). Then deleted the /Developer directory.
• Went to the AppStore and downloaded Xcode.
• Launched Xcode and went into the Preferences -> Downloads, and installed the command line tools.

Answer 2

On Ubuntu(18.04)

i was able to solve this issue by running the following:

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

reference

Answer 3

I just wanted to add this answer specifically for Mac Users.

My server was running perfectly fine until I updated my xcode. The while starting my rails server the error was shown like this

Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /Users/user/.rvm/rubies/ruby-1.9.3-p448/bin/ruby extconf.rb --with-mysql-
    checking for rb_thread_blocking_region()... /Users/user/.rvm/rubies/ruby-1.9.3-  
    p448/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an    
    executable file. (RuntimeError)

And there was suggestion to install mysql2 gem at the end of the error message. So when i tried installing it I got the error as above mentioned in this question. The error I got is as follows

ERROR:  Error installing mysql2:
ERROR: Failed to build gem native extension.

So as suggested in this post I tried 'brew install mysql' and that quitted saying that mysql version so and so already installed. But there was warning before it saying

Warning: You have not agreed to the Xcode license.
Builds will fail! Agree to the license by opening Xcode.app or running:
xcodebuild -license

Then I tried this sudo xcodebuild -license and type 'agree' at the end. You have to be root to agree to the license.

After this, I again tried bundle install and then everything is working fine as normal. [ Even due to this xcode updation, I had problem with my tower also.]

Answer 4

If you are using yum try:

sudo yum install mysql-devel

Answer 5

libmysql-ruby has been phased out and replaced. New command:

 sudo apt-get install ruby-mysql libmysqlclient-dev

Answer 6

If you are still having trouble….

Try installing

   sudo apt-get install ruby1.9.1-dev