与Sinatra的ActiveRecord :: ConnectionTimeoutError

Question

我正在开发一个带有ActiveRecord和SQLite的模块化Sinatra应用程序。超过连接池大小后，我继续遇到ActiveRecord::ConnectionTimeoutError could not obtain a database connection within 5.000 seconds (waited 5.001 seconds)。

我尝试了以下所有方法：

来自here 的
1. use ActiveRecord::ConnectionAdapater::ConnectionManagement 来自here
的
2. after { ActiveRecord::Base.connection.close } 来自here
的
3. ActiveRecord::Base.clear_active_connections!

   然而，我仍然继续犯同样的错误！

    # Gemfile
   source 'https://rubygems.org'
   ruby '2.0.0'
   
   gem 'activerecord', '~> 4.0.2'
   gem 'sass', '~> 3.2.12'
   gem 'sinatra', '~> 1.4.4'
   gem 'sinatra-activerecord'
   gem 'sinatra-assetpack', '~> 0.3.1'
   gem 'sinatra-contrib', '~> 1.4.2'
   gem 'slim', '~> 2.0.2'
   
   group :development do
     gem 'tux'
     gem 'sqlite3'
   end
   
   group :production do
     gem 'pg'
   end
   
   group :test do
     gem 'database_cleaner'
     gem 'factory_girl', '~> 4.3.0'
     gem 'rspec'
   end
   
   # environments.rb
   config :development do
     ActiveRecord::Base.establish_connection(
       adapter: 'sqlite3',
       database: 'local.db'
     )
   end