mysql2: uninitialized constant Mysql2::Client::SECURE_CONNECTION (NameError)

I’m trying to get my application running on a windows server but when running rails server I get the below error. I have installed MySQL and ran the bundle install.

C:\myapp> rails server -e production
=> Booting WEBrick
=> Rails 4.1.2.rc1 application starting in production on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Notice: server is listening on all interfaces (0.0.0.0). Consider using 127.0.0.1 (--binding option)
=> Ctrl-C to shutdown server
Exiting
C:/Ruby22/lib/ruby/gems/2.2.0/gems/mysql2-0.3.16/lib/mysql2/client.rb:12:in `<class:Client>': uninitialized constant Mysql2::Client::SECURE_CONNECTION (NameError)
C:/Ruby22/lib/ruby/gems/2.2.0/gems/mysql2-0.3.16/lib/mysql2/client.rb:12:in `<class:Client>': uninitialized constant Mys
ql2::Client::SECURE_CONNECTION (NameError)
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/mysql2-0.3.16/lib/mysql2/client.rb:2:in `<module:Mysql2>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/mysql2-0.3.16/lib/mysql2/client.rb:1:in `<top (required)>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/mysql2-0.3.16/lib/mysql2.rb:10:in `<top (required)>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activerecord-4.1.2.rc1/lib/active_record/connection_adapters/mysql2_adap
ter.rb:4:in `<top (required)>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activerecord-4.1.2.rc1/lib/active_record/connection_adapters/connection_
specification.rb:188:in `spec'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activerecord-4.1.2.rc1/lib/active_record/connection_handling.rb:50:in `e
stablish_connection'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activerecord-4.1.2.rc1/lib/active_record/railtie.rb:129:in `block (2 lev
els) in <class:Railtie>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activesupport-4.1.2.rc1/lib/active_support/lazy_load_hooks.rb:38:in `ins
tance_eval'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activesupport-4.1.2.rc1/lib/active_support/lazy_load_hooks.rb:38:in `exe
cute_hook'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activesupport-4.1.2.rc1/lib/active_support/lazy_load_hooks.rb:28:in `blo
ck in on_load'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activesupport-4.1.2.rc1/lib/active_support/lazy_load_hooks.rb:27:in `eac
h'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activesupport-4.1.2.rc1/lib/active_support/lazy_load_hooks.rb:27:in `on_
load'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/activerecord-4.1.2.rc1/lib/active_record/railtie.rb:118:in `block in <cl
ass:Railtie>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/initializable.rb:30:in `instance_exec'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/initializable.rb:30:in `run'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/initializable.rb:55:in `block in run_initia
lizers'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:226:in `block in tsort_each'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:429:in `each_strongly_connected_component_from'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:347:in `block in each_strongly_connected_component'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:345:in `each'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:345:in `call'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:345:in `each_strongly_connected_component'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:224:in `tsort_each'
        from C:/Ruby22/lib/ruby/2.2.0/tsort.rb:203:in `tsort_each'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/initializable.rb:54:in `run_initializers'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/application.rb:300:in `initialize!'
        from C:/myapp/config/environment.rb:5:in `<top (required)>'
        from C:/myapp/config.ru:3:in `block in <main>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
        from C:/myapp/config.ru:in `new'
        from C:/myapp/config.ru:in `<main>'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'

        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/server.rb:50:in `app'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/rack-1.5.2/lib/rack/server.rb:250:in `start'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/server.rb:69:in `start'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/commands_tasks.rb:81:in `block in
server'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/commands_tasks.rb:76:in `tap'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/commands_tasks.rb:76:in `server'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands/commands_tasks.rb:40:in `run_comma
nd!'
        from C:/Ruby22/lib/ruby/gems/2.2.0/gems/railties-4.1.2.rc1/lib/rails/commands.rb:17:in `<top (required)>'
        from bin/rails:4:in `require'
        from bin/rails:4:in `<main>'

About this issue

Original URL
State: closed
Created 9 years ago
Comments: 31 (1 by maintainers)

Commits related to this issue

Upgrade mysql2 Fixes "uninitialized constant Mysql2::Client::SECURE_CONNECTION". Related to https://github.com/brianmario/mysql2/issues/603 — committed to mconf/bigbluebutton_rails by daronco 8 years ago

Most upvoted comments

Quick brew bash rundown for those coming from SEO channel:

$ brew tap homebrew/versions
$ brew update
$ brew uninstall mysql mysql2 # probs auto updated to 5.7
$ brew install mysql56 # 5.6 locked version
# copy in the launchctrl output
$ gem uninstall mysql mysql2 # uninstall legacy gems
$ bundle install # to install / rebuild new refs

+32

tomfuertes on Nov 15, 2015

@zouqilin As I wrote above, you will need the mysql2 gem version 0.3.17 or higher to run with MySQL 5.7.

+17

sodabrew on Nov 22, 2015

@tomfuertes mysql2 gem 0.3.17 and 0.2.24 and above support MySQL 5.7. Directing people to downgrade to MySQL 5.6 is not necessary.

+13

sodabrew on Nov 15, 2015

Please use mysql2 0.3.18 for more reliable windows builds.

sodabrew on Mar 25, 2015

paralaks on Jan 2, 2017

Thanks, changing to mysql2 gem to 0.2.24 worked !!

aashish on Dec 14, 2015

@sodabrew Thanks. Finding the right version of mysql2 was the key. “0.3.15” couldn’t handle the new mysql I homebrew installed, and “0.4…” was too new for my rails 3.2 (I think). “0.3.17” is working.

Arcolye on Dec 2, 2015

You must use mysql2 series 0.2.x with Rails 2.3.x. I believe that mysql2 version 0.2.24 contains the necessary change to work with MySQL 5.7.

sodabrew on Dec 14, 2015

Like @Arcolye the gem 'mysql2', '0.3.17' worked for me too.

wellington1993 on Jul 30, 2018

@paralaks Supporting MySQL 5.7 was added in 0.3.17 and higher.

Here’s the compatibility table for Rails and mysql2 versions: https://github.com/brianmario/mysql2/blob/master/README.md#compatibility

To fix your problem you should upgrade your mysql2 gem version or downgrade MySQL.

ghost on Jan 31, 2017

@sodabrew 0.3.17 has done it, thanks!

oholubyev on Dec 12, 2015

I downgraded to ruby 2.0.0 and no longer receive this error. Closing

jostster on Mar 25, 2015