[mysql] Error installing mysql2: Failed to build gem native extension

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 mysql2 it gives me the following error:

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

How can I fix this and successfully install mysql2?

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.]

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.

I have several computers, 32 and 64 bits processor, they run on Ubuntu Linux, Maverick (10.10) release.

I had the same problem, and for me, the sudo apt-get install libmysql-ruby libmysqlclient-dev did the job!!!

You are getting this problem because you have not install MySql. Before install mysql2 gem. Install MySQL. After that mysql2 gem will install.

If you are still having trouble….

Try installing

   sudo apt-get install ruby1.9.1-dev

I'm on a mac and use homebrew to install open source programs. I did have to install mac Dev tools in order to install homebrew, but after that it was a simple:

brew install mysql

to install mysql. I haven't had a mysql gem problem since.

I got the gem built on Mac OS X 10.6.6 by 1) Ensuring the Developer tools package is installed 2) Downloading the current MySQL package (5.5.8 in my case) from Source 3) Installing the cmake tool from cmake.org 4) Following the instructions in section 2.11 of INSTALL-SOURCE from the mysql distribution files 5) sudo gem install mysql2 -- --srcdir=/usr/local/mysql/include The gem built successfully, but there are two errors in the documentation that rdoc and ri complain about. But now when I try to require 'mysql2' I get a

LoadError: no such file to load -- mysql2/mysql2

I was hoping the error I would get was that the libmysqlclient.16.dylib couldn't be found because we figured that out in another post (search for install_name_tool).

My $PATH has /usr/local/mysql in it (that's where my source and built files are located), so I'm a little stumped. If anyone has any thoughts, I'll check back after a few hours of sleep.

Solution only works on Mac OS X

If you've installed MySQL with homebrew, what worked for me was uninstalling MySQL, and installing MySQL Community Edition via the MySQL website (https://www.mysql.com/).

After installed, just re-enter the command to gem install mysql2 or if necessary, sudo gem install mysql2, if you are getting permission denied problems.

Have you tried using

 gem install mysql -- --with-mysql-lib=/usr/lib/mysql/lib 

to specify the location of thebase directory as well as the path to the MySQL libraries that are necessary to complete the gem installation?

Sources: MySQL Gem Install ERROR: Failed to build gem native extension MySQL Forums :: Ruby :: Help needed with installing MySQL binding for Ruby

After you get the mysql-dev issues corrected, you may need to remove the bad mysql2 install. Look carefully at the messages after $ bundle install. You may need to

rm -rf vendor/cache/
rm -rf ./Zentest

This will clear out the bad mysql2 installation so that a final $ bundle install can create a good one.

download the right version of mysqllib.dll then copy it to ruby bin really works for me. Follow this link plases mysql2 gem compiled for wrong mysql client library

This solved my problem once in Windows:

subst X: "C:\Program files\MySQL\MySQL Server 5.5" 
gem install mysql2 -v 0.x.x --platform=ruby -- --with-mysql-dir=X: --with-mysql-lib=X:\lib\opt 
subst X: /D

Another way for MacOS users

If you used "brew" to install mysql:

gem install mysql2 -v 'x.x.x' -- --with-mysql-config=/usr/local/Cellar/mysql/y.y.y/bin/mysql_config

x.x.x = version of the mysql2 gem you want to install
y.y.y = the version of mysql you have installed ls /usr/local/Cellar/mysql to find it.

On Debian Stretch the package that worked for me was default-libmysqlclient-dev

sudo apt-get update && apt-get install -y default-libmysqlclient-dev

If still getting error then follow the steps of mysql2 gem installation on Rails 3 on -

http://rorguide.blogspot.com/2011/03/installing-mysql2-gem-on-ruby-192-and.html

where most of the user were able to install mysql2 gem.

I had this issue on Windows 7. This is apparently an incompatibility issue and the solution is as follows:

Download the libmySQL.dll file from an older InstantRails installer. It is available from the InstantRails GitHub repo.

Next, copy that file into your Ruby/bin folder.

Now, you are good to go ;)

I got this error too. Solved by installing development packages. I'm using arch and it was:

sudo pacman -S base-devel

which installed:

m4, autoconf, automake, bison, fakeroot, flex, libmpc, ppl, cloog-ppl, elfutils, gcc,
libtool, make, patch, pkg-config

but I think it actually needed make and gcc. Error output said (on my machine, among other):

"You have to install development tools first."

So it was an obvious decision and it helped.

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

 sudo apt-get install ruby-mysql libmysqlclient-dev

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

If you are using yum try:

sudo yum install mysql-devel

I was running into this error on my mac and found that I needed to upgrade from mysql 32bit to mysql 64 bit to get this error to go away. I was running OSX 10.6 on an intel macbook pro with ruby 1.9.2 and rails3.0.0

I also needed to install xcode in order to get unix utilities like "make" that are required to compile the gem.

once this was done I was able to run gem install mysql and gem install mysql2 without error.

For windows user: You set the lib and include path of your mysql, for instance, if youre using xampp you can have like this:

gem install mysql2 -- '--with-mysql-lib="C:\xampp\mysql\lib" --withmysql-include="C:\xampp\mysql\include"'

You have to Install some dependencies

sudo apt-get install libmysql-ruby libmysqlclient-dev

here is a solution for the windows users, hope it helps!

Using MySQL with Rails 3 on Windows

• Install railsinstaller -> www.railsinstaller.org (I installed it to c:\Rails)

• Install MySQL (I used MySQL 5.5) -> dev.mysql.com/downloads/installer/

--- for mySQL installation ---

If you dont already have these two files installed you might need them to get your MySQL going

vcredist_x86.exe -> http://www.microsoft.com/download/en/details.aspx?id=5555 dotNetFx40_Full_x86_x64.exe -> http://www.microsoft.com/download/en/details.aspx?id=17718

Use default install Developer Machine

-MySQL Server Config-
port: 3306
windows service name: MySQL55
mysql root pass: root (you can change this later)
(username: root)
-MySQL Server Config-

--- for mySQL installation ---

--- Install the mysql2 Gem ---

Important: Do this with Git Bash Command Line(this was installed with railsinstaller) -> start/Git Bash

gem install mysql2 -- '--with-mysql-lib="c:\Program Files\MySQL\MySQL Server 5.5\lib" --with-mysql-include="c:\Program Files\MySQL\MySQL Server 5.5\include"'

Now the gem should have installed correctly

Lastly copy the libmysql.dll file from
C:\Program Files\MySQL\MySQL Server 5.5\lib
to
C:\Rails\Ruby1.9.2\bin

--- Install the mysql2 Gem ---

You will now be able to use your Rails app with MySQL, if you are not sure how to create a Rails 3 app with MySQL read on...

--- Get a Rails 3 app going with MySQL ---

Open command prompt(not Git Bash) -> start/cmd
Navigate to your folder (c:\Sites)
Create new rails app

rails new world

Delete the file c:\Sites\world\public\index.html
Edit the file c:\Sites\world\config\routes.rb
add this line -> root :to => 'cities#index'

Open command prompt (generate views and controllers)

rails generate scaffold city ID:integer Name:string CountryCode:string District:string Population:integer

Edit the file c:\Sites\world\app\models\city.rb to look like this

class City < ActiveRecord::Base
 set_table_name "city"
end

Edit the file c:\Sites\world\config\database.yml to look like this

development:
adapter: mysql2
encoding: utf8
database: world
pool: 5
username: root
password: root
socket: /tmp/mysql.sock

add to gemfile

gem 'mysql2'

Open command prompt windows cmd, not Git Bash(run your app!)
Navigate to your app folder (c:\Sites\world)

rails s

Open your browser here -> http://localhost:3000

--- Get a Rails 3 app going with MySQL ---

For MacOS Mojave:

gem install mysql2 -v '0.5.2' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include

In my case this helped:

$ export LDFLAGS="-L/usr/local/opt/openssl/lib"
$ export CPPFLAGS="-I/usr/local/opt/openssl/include"

Then:

gem install mysql2 -v '0.5.2' --source 'https://rubygems.org/' -- --with-cppflags=-I/usr/local/opt/openssl/include --with-ldflags=-L/usr/local/opt/openssl/lib

Result:

Building native extensions with: '--with-cppflags=-I/usr/local/opt/openssl/include --with-ldflags=-L/usr/local/opt/openssl/lib'
This could take a while...
Successfully installed mysql2-0.5.2
Parsing documentation for mysql2-0.5.2
Installing ri documentation for mysql2-0.5.2
Done installing documentation for mysql2 after 0 seconds
1 gem installed

See this post (WARNING: Japanese language inside).