Rails: mysql load error when starting rails server - mysql

Question

I am trying to migrate my rails application from rails version 3 to rails version 4.I have install mysql2 gem in my rails application and trying to run a rails server but I am getting below error.
C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-4.0.0/lib/act
ive_support/dependencies.rb:228:in `require': cannot load such file -- mysql2/2.
0/mysql2 (LoadError)
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:228:in `block in require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:228:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/mysql2-0.3.11-
x86-mingw32/lib/mysql2/mysql2.rb:2:in `<top (required)>'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:228:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:228:in `block in require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:213:in `load_dependency'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/activesupport-
4.0.0/lib/active_support/dependencies.rb:228:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/mysql2-0.3.11-
x86-mingw32/lib/mysql2.rb:9:in `<top (required)>'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:76:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:72:in `each'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:72:in `block in require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:61:in `each'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler/runtime.rb:61:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/bundler-1.7.7/
lib/bundler.rb:133:in `require'
from E:/JCI-stable-final-Version-7-AoneSms/onspot-rails4.0.0/config/appl
ication.rb:12:in `<top (required)>'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.0.0
/lib/rails/commands.rb:76:in `require'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.0.0
/lib/rails/commands.rb:76:in `block in <top (required)>'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.0.0
/lib/rails/commands.rb:73:in `tap'
from C:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/railties-4.0.0
/lib/rails/commands.rb:73:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Below is my gemfile
source 'http://rubygems.org'
gem 'gmaps4rails'
gem 'geocoder'
gem 'groupdate'
gem "chartkick"
gem "paperclip"
gem "easy_captcha"
gem "rails_email_validator"
gem "devise_security_extension"
gem "will_paginate"
gem "prawn-labels"
gem "rails-xmlrpc"
gem "rqrcode_png"
gem "rqrcode"
gem "blueprint-rails"
gem "mysql2" , "0.3.11"
gem "jeweler"
#gem "activesupport"
#gem "activerecord"
#gem "activerecord-import"
#gem "activerecord-mysql-adapter"
#gem "mysql"
gem "yaml_db"
gem "tabulous"
gem "thin"
gem 'rails', '4.0.0'
gem "rake"
gem 'jquery-ui-rails'
gem 'cancan'
gem 'rolify'
gem 'rails_admin'
gem 'fastercsv'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
#gem 'sqlite3'
gem "devise"
#gem "devise", "~> 1.5.3"
#gem "orm_adapter", "~> 0.0.3"
gem 'json'
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails', '~> 4.0.0'
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', :platforms => :ruby
gem 'uglifier', '>= 1.3.0'
end
gem 'jquery-rails'
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# To use Jbuilder templates for JSON
# gem 'jbuilder'
# Use unicorn as the app server
# gem 'unicorn'
# Deploy with Capistrano
gem 'capistrano'
#gem 'css-bootstrap-rails'
# To use debugger
# gem 'ruby-debug'
gem 'impressionist'
gem 'devise-encryptable'
gem "devise_invitable"
Please help.
Thanks

Answer 1

gem uninstall mysql2
Download last MySQL connector from
http://cdn.mysql.com/Downloads/Connector-C/mysql-connector-c-noinstall-6.0.2-win32.zip
Extract it to C:\connector-6.0.2
gem install mysql2 --platform=ruby -- '--with-mysql-lib="C:\connector-6.0.2\lib" --with-mysql-include="C:\connector-6.0.2\include" --with-mysql-dir="C:\connector-6.0.2"'
If after installing the gem, you get an error:
"The specified module could not be found.
C:/Devel/Ruby200/lib/ruby/gems/2.0.0/gems/mysql2-0.3.11/lib/mysql2/mysql2.so"
Then copy "libmysql.dll" to Ruby's bin folder.
If still you are unable to fix this issue, have a look at this article:
http://www.codeproject.com/Tips/798700/Install-Rails-and-MySQL-Server-on-Windows
Give a try, above trick might help.
But truly, try moving to linux machine. Windows is never recommended for rails development.