Question

I recently switched my rails database over from sqlite3 to mysql, and since doing it I’ve had a ConnectionNotEstablished error when trying to access my server.

Here is the full stack trace of the error.

ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished):
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:404:in `retrieve_connection'
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_specification.rb:170:in `retrieve_connection'
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_specification.rb:144:in `connection'
  activerecord (3.2.8) lib/active_record/query_cache.rb:67:in `rescue in call'
  activerecord (3.2.8) lib/active_record/query_cache.rb:61:in `call'
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `_run__318842653__call__302530175__callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/reloader.rb:65:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.8) lib/rails/rack/logger.rb:26:in `call_app'
  railties (3.2.8) lib/rails/rack/logger.rb:16:in `call' 
  actionpack (3.2.8) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.8) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/static.rb:62:in `call'
  railties (3.2.8) lib/rails/engine.rb:479:in `call'
  railties (3.2.8) lib/rails/application.rb:223:in `call'
  rack (1.4.1) lib/rack/content_length.rb:14:in `call'
  railties (3.2.8) lib/rails/rack/log_tailer.rb:17:in `call'
  rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
  /home/aaron/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /home/aaron/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /home/aaron/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

The connection with the database seems to be working fine. I can run db:migrate and it runs fine, as well as Rails console, and I can access the data and everything just fine.
I’ve noticed that when I boot up, the error works slightly different depending on the environment. It seems to run fine in test. In development, it throws the error when I visit the page in the browser, and in production it throws the error when I boot it up.

The problem seems pretty much identical to what was presented here:
Rails and MySQL – ActiveRecord::ConnectionNotEstablished in production environment,
but none of the answers worked for me.

I have all the code pushed up here: https://github.com/Aaronneyer/aaronneyer.com

Answer 1

Still not sure what was the exact cause of this, but I was able to solve it by removing the newrelic gem, which was no longer being used anyways.