Fixed that each request with the WEBrick adapter would open a new database...

Fixed that each request with the WEBrick adapter would open a new database connection #1685 [Sam Stephenson]. Added ActiveRecord::Base.threaded_connections flag to turn off 1-connection per thread (required for thread safety). By default it's on, but WEBrick in Rails need it off #1685 [Sam Stephenson]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1792 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Added ActiveRecord::Base.threaded_connections flag to turn off 1-connection per thread (required for thread safety). By default it's on, but WEBrick in Rails need it off #1685 [Sam Stephenson]
+
 * Correct reflected table name for singular associations.  #1688 [court3nay@gmail.com]
 
 * Fixed optimistic locking with SQL Server #1660 [tom@popdog.net]

activerecord/lib/active_record/base.rb

@@ -289,6 +289,11 @@ def self.inherited(child) #:nodoc:
     # This is set to :local by default.
     cattr_accessor :default_timezone
     @@default_timezone = :local
+    
+    # Determines whether or not to use a connection for each thread, or a single shared connection for all threads.
+    # Defaults to true; Railties' WEBrick server sets this to false.
+    cattr_accessor :threaded_connections
+    @@threaded_connections = true
 
     class << self # Class methods
       # Find operates with three different retreval approaches:

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -86,6 +86,14 @@ def self.establish_connection(spec = nil)
       end
     end
 
+    def self.active_connections #:nodoc:
+      if threaded_connections
+        Thread.current['active_connections'] ||= {}
+      else
+        @@active_connections ||= {}
+      end
+    end
+
     # Locate the connection of the nearest super class. This can be an
     # active or defined connections: if it is the latter, it will be
     # opened and set as the active connection for the class it was defined
@@ -94,7 +102,7 @@ def self.retrieve_connection #:nodoc:
       klass = self
       ar_super = ActiveRecord::Base.superclass
       until klass == ar_super
-        if conn = (Thread.current['active_connections'] ||= {})[klass]
+        if conn = active_connections[klass]
           return conn
         elsif conn = @@defined_connections[klass]
           klass.connection = conn
@@ -109,7 +117,7 @@ def self.retrieve_connection #:nodoc:
     def self.connected?
       klass = self
       until klass == ActiveRecord::Base.superclass
-        if Thread.current['active_connections'].is_a?(Hash) && Thread.current['active_connections'][klass]
+        if active_connections[klass]
           return true
         else
           klass = klass.superclass
@@ -125,8 +133,7 @@ def self.connected?
     def self.remove_connection(klass=self)
       conn = @@defined_connections[klass]
       @@defined_connections.delete(klass)
-      Thread.current['active_connections'] ||= {}
-      Thread.current['active_connections'][klass] = nil
+      active_connections[klass] = nil
       conn.config if conn
     end
 
@@ -134,8 +141,7 @@ def self.remove_connection(klass=self)
     def self.connection=(spec)
       raise ConnectionNotEstablished unless spec
       conn = self.send(spec.adapter_method, spec.config)
-      Thread.current['active_connections'] ||= {}
-      Thread.current['active_connections'][self] = conn
+      active_connections[self] = conn
     end
 
     # Converts all strings in a hash to symbols.

activerecord/lib/active_record/query_cache.rb

@@ -51,8 +51,7 @@ def self.connection=(spec)
         QueryCache.new(self.send(spec.adapter_method, spec.config)) :
         self.send(spec.adapter_method, spec.config)
       
-      Thread.current['active_connections'] ||= {}
-      Thread.current['active_connections'][self] = conn
+      active_connections[self] = conn
     end
   end
   

activerecord/test/threaded_connections_test.rb

+require 'abstract_unit'
+
+class ThreadedConnectionsTest < Test::Unit::TestCase
+  self.use_transactional_fixtures = false
+
+  fixtures :topics
+
+  def setup
+    @connection = ActiveRecord::Base.remove_connection
+    @connections = []
+  end
+  
+  def gather_connections(use_threaded_connections)
+    ActiveRecord::Base.threaded_connections = use_threaded_connections
+    ActiveRecord::Base.establish_connection(@connection)
+    
+    5.times do
+      Thread.new do
+        Topic.find :first
+        @connections << ActiveRecord::Base.active_connections.values.first
+      end.join
+    end
+  end
+
+  def test_threaded_connections
+    gather_connections(true)
+    assert_equal @connections.uniq.length, 5
+  end
+
+  def test_unthreaded_connections
+    gather_connections(false)
+    assert_equal @connections.uniq.length, 1
+  end
+end

railties/CHANGELOG

 *SVN*
 
+* Fixed that each request with the WEBrick adapter would open a new database connection #1685 [Sam Stephenson]
+
 * Added support for SQL Server in the database rake tasks #1652 [ken.barker@gmail.com] Note: osql and scptxfr may need to be installed on your development environment. This involves getting the .exes and a .rll (scptxfr) from a production SQL Server (not developer level SQL Server). Add their location to your Environment PATH and you are all set.
 
 * Added a VERSION parameter to the migrate task that allows you to do "rake migrate VERSION=34" to migrate to the 34th version traveling up or down depending on the current version

railties/lib/webrick_server.rb

@@ -8,6 +8,8 @@
 
 ABSOLUTE_RAILS_ROOT = File.expand_path(RAILS_ROOT)
 
+ActiveRecord::Base.threaded_connections = false
+
 class CGI
   def stdinput
     @stdin || $stdin