Active_support / dependencies.rb：247`require’：无法加载此类文件 – 2.1 / pg_ext（LoadError）
我在Windows机器上使用Ruby 2.1.5，Rails 4.1.6和PostgreSQL 9.3.5。
当我尝试bundle exec rails server ，我最终得到以下错误：
DL is deprecated, please use Fiddle c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require': cannot load such file -- 2.1/pg_ext (LoadError) from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `block in re...re' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:232:in `load_dependancy' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:247:in `require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:10:in `rescue in ' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/pg-0.17.1-x86-mingw32/lib/pg.rb:3:in `' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:76:in `block (2 levels) in require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `each' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:72:in `block in require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `each' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler/runtime.rb:61:in `require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/bundler-1.7.7/lib/bundler.rb:133:in `require' from C:/....../config/application.rb:5:in `' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `require' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `block in server from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `tap' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `server' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:40:in `run_command!' from c:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.6/lib/rails/commands.rb:17:in `' from bin/rails:8:in `require' from bin/rails:8:in `'
我需要使用更新版本的pg gem：
gem 'pg', '~> 0.18.0.pre20141117110243'
更新后，有时会发生。
尝试删除所有gem并重新安装。 喜欢
rm -rf ./vendor/bundle bundle install