Make clear_active_connections! also return stale connections back to the pool

- also clean up some cruft remaining from per-thread connection cache

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -60,11 +60,11 @@ def initialize(spec)
       # #connection can be called any number of times; the connection is
       # held in a hash keyed by the thread id.
       def connection
-        if conn = @reserved_connections[active_connection_name]
+        if conn = @reserved_connections[current_connection_id]
           conn.verify!(verification_timeout)
           conn
         else
-          @reserved_connections[active_connection_name] = checkout
+          @reserved_connections[current_connection_id] = checkout
         end
       end
 
@@ -72,7 +72,7 @@ def connection
       # #release_connection releases the connection-thread association
       # and returns the connection to the pool.
       def release_connection
-        conn = @reserved_connections.delete(active_connection_name)
+        conn = @reserved_connections.delete(current_connection_id)
         checkin conn if conn
       end
 
@@ -118,14 +118,20 @@ def clear_reloadable_connections!
       # Verify active connections and remove and disconnect connections
       # associated with stale threads.
       def verify_active_connections! #:nodoc:
-        remove_stale_cached_threads!(@reserved_connections) do |name, conn|
-          checkin conn
-        end
+        clear_stale_cached_connections!
         connections.each do |connection|
           connection.verify!(verification_timeout)
         end
       end
 
+      # Return any checked-out connections back to the pool by threads that
+      # are no longer alive.
+      def clear_stale_cached_connections!
+        remove_stale_cached_threads!(@reserved_connections) do |name, conn|
+          checkin conn
+        end
+      end
+
       # Check-out a database connection from the pool.
       def checkout
         raise NotImplementedError, "checkout is an abstract method"
@@ -156,7 +162,7 @@ def new_connection
         ActiveRecord::Base.send(spec.adapter_method, config)
       end
 
-      def active_connection_name #:nodoc:
+      def current_connection_id #:nodoc:
         Thread.current.object_id
       end
 
@@ -178,12 +184,6 @@ def remove_stale_cached_threads!(cache, &block)
     # NewConnectionEveryTime is a simple implementation: always
     # create/disconnect on checkout/checkin.
     class NewConnectionEveryTime < ConnectionPool
-      def active_connection
-        @reserved_connections[active_connection_name]
-      end
-
-      def active_connections; @reserved_connections; end
-
       def checkout
         new_connection
       end
@@ -288,19 +288,14 @@ def establish_connection(name, spec)
         @connection_pools[name] = ConnectionAdapters::ConnectionPool.create(spec)
       end
 
-      # for internal use only and for testing;
-      # only works with ConnectionPerThread pool class
-      def active_connections #:nodoc:
-        @connection_pools.inject({}) do |hash,kv|
-          hash[kv.first] = kv.last.active_connection
-          hash.delete(kv.first) unless hash[kv.first]
-          hash
-        end
-      end
-
-      # Clears the cache which maps classes to connections.
+      # Returns any connections in use by the current thread back to the pool,
+      # and also returns connections to the pool cached by threads that are no
+      # longer alive.
       def clear_active_connections!
-        @connection_pools.each_value {|pool| pool.release_connection }
+        @connection_pools.each_value do |pool|
+          pool.release_connection
+          pool.clear_stale_cached_connections!
+        end
       end
 
       # Clears the cache which maps classes
@@ -353,11 +348,9 @@ def retrieve_connection_pool(klass)
       end
 
       # Apply monitor to all public methods that access the pool.
-      synchronize :establish_connection, :retrieve_connection,
-        :connected?, :remove_connection, :active_connections,
-        :clear_active_connections!, :clear_reloadable_connections!,
-        :clear_all_connections!, :verify_active_connections!,
-        :with => :connection_pools_lock
+      synchronize :establish_connection, :retrieve_connection, :connected?, :remove_connection,
+        :clear_active_connections!, :clear_reloadable_connections!, :clear_all_connections!,
+        :verify_active_connections!, :with => :connection_pools_lock
     end
   end
 end
\ No newline at end of file

activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb

@@ -124,9 +124,8 @@ def remove_connection(klass = self)
         connection_handler.remove_connection(klass)
       end
 
-      delegate :active_connections, :clear_active_connections!,
-        :clear_reloadable_connections!, :clear_all_connections!,
-        :verify_active_connections!, :to => :connection_handler
+      delegate :clear_active_connections!, :clear_reloadable_connections!,
+        :clear_all_connections!,:verify_active_connections!, :to => :connection_handler
     end
   end
 end

activerecord/test/cases/locking_test.rb

@@ -280,7 +280,6 @@ def duel(zzz = 5)
               sleep zzz       # block thread 2 for zzz seconds
             end
             t1 = Time.now
-            Person.clear_active_connections!
           end
 
           b = Thread.new do
@@ -288,7 +287,6 @@ def duel(zzz = 5)
             t2 = Time.now
             Person.transaction { yield }
             t3 = Time.now
-            Person.clear_active_connections!
           end
 
           a.join

activerecord/test/cases/pooled_connections_test.rb

+require "cases/helper"
+
+class PooledConnectionsTest < ActiveRecord::TestCase
+  def setup
+    super
+    @connection = ActiveRecord::Base.remove_connection
+  end
+
+  def teardown
+    ActiveRecord::Base.clear_all_connections!
+    ActiveRecord::Base.establish_connection(@connection)
+    super
+  end
+
+  def checkout_connections
+    ActiveRecord::Base.establish_connection(@connection.merge({:pool => 2, :wait_timeout => 0.3}))
+    @connections = []
+    @timed_out = 0
+
+    4.times do
+      Thread.new do
+        begin
+          @connections << ActiveRecord::Base.connection_pool.checkout
+        rescue ActiveRecord::ConnectionTimeoutError
+          @timed_out += 1
+        end
+      end.join
+    end
+  end
+
+  def test_pooled_connection_checkout
+    checkout_connections
+    assert_equal @connections.length, 2
+    assert_equal @timed_out, 2
+  end
+
+  def checkout_checkin_connections(pool_size, threads)
+    ActiveRecord::Base.establish_connection(@connection.merge({:pool => pool_size, :wait_timeout => 0.5}))
+    @connection_count = 0
+    @timed_out = 0
+    threads.times do
+      Thread.new do
+        begin
+          conn = ActiveRecord::Base.connection_pool.checkout
+          sleep 0.1
+          ActiveRecord::Base.connection_pool.checkin conn
+          @connection_count += 1
+        rescue ActiveRecord::ConnectionTimeoutError
+          @timed_out += 1
+        end
+      end.join
+    end
+  end
+
+  def test_pooled_connection_checkin_one
+    checkout_checkin_connections 1, 2
+    assert_equal 2, @connection_count
+    assert_equal 0, @timed_out
+  end
+
+  def test_pooled_connection_checkin_two
+    checkout_checkin_connections 2, 3
+    assert_equal 3, @connection_count
+    assert_equal 0, @timed_out
+  end
+
+  def test_pooled_connection_checkout_existing_first
+    ActiveRecord::Base.establish_connection(@connection.merge({:pool => 1}))
+    conn_pool = ActiveRecord::Base.connection_pool
+    conn = conn_pool.checkout
+    conn_pool.checkin(conn)
+    conn = conn_pool.checkout
+    assert ActiveRecord::ConnectionAdapters::AbstractAdapter === conn
+    conn_pool.checkin(conn)
+  end
+end unless %w(FrontBase).include? ActiveRecord::Base.connection.adapter_name
+
+class AllowConcurrencyDeprecatedTest < ActiveRecord::TestCase
+  def test_allow_concurrency_is_deprecated
+    assert_deprecated('ActiveRecord::Base.allow_concurrency') do
+      ActiveRecord::Base.allow_concurrency
+    end
+    assert_deprecated('ActiveRecord::Base.allow_concurrency=') do
+      ActiveRecord::Base.allow_concurrency = true
+    end
+  end
+end

activerecord/test/cases/threaded_connections_test.rb

-require "cases/helper"
-require 'models/topic'
-require 'models/reply'
-
-unless %w(FrontBase).include? ActiveRecord::Base.connection.adapter_name
-  class ThreadedConnectionsTest < ActiveRecord::TestCase
-    def test_allow_concurrency_is_deprecated
-      assert_deprecated('ActiveRecord::Base.allow_concurrency') do
-        ActiveRecord::Base.allow_concurrency
-      end
-      assert_deprecated('ActiveRecord::Base.allow_concurrency=') do
-        ActiveRecord::Base.allow_concurrency = true
-      end
-    end
-  end
-
-  class PooledConnectionsTest < ActiveRecord::TestCase
-    def setup
-      super
-      @connection = ActiveRecord::Base.remove_connection
-    end
-
-    def teardown
-      ActiveRecord::Base.clear_all_connections!
-      ActiveRecord::Base.establish_connection(@connection)
-      super
-    end
-
-    def checkout_connections
-      ActiveRecord::Base.establish_connection(@connection.merge({:pool => 2, :wait_timeout => 0.3}))
-      @connections = []
-      @timed_out = 0
-
-      4.times do
-        Thread.new do
-          begin
-            @connections << ActiveRecord::Base.connection_pool.checkout
-          rescue ActiveRecord::ConnectionTimeoutError
-            @timed_out += 1
-          end
-        end.join
-      end
-    end
-
-    def test_pooled_connection_checkout
-      checkout_connections
-      assert_equal @connections.length, 2
-      assert_equal @timed_out, 2
-    end
-
-    def checkout_checkin_connections(pool_size, threads)
-      ActiveRecord::Base.establish_connection(@connection.merge({:pool => pool_size, :wait_timeout => 0.5}))
-      @connection_count = 0
-      @timed_out = 0
-      threads.times do
-        Thread.new do
-          begin
-            conn = ActiveRecord::Base.connection_pool.checkout
-            sleep 0.1
-            ActiveRecord::Base.connection_pool.checkin conn
-            @connection_count += 1
-          rescue ActiveRecord::ConnectionTimeoutError
-            @timed_out += 1
-          end
-        end.join
-      end
-    end
-
-    def test_pooled_connection_checkin_one
-      checkout_checkin_connections 1, 2
-      assert_equal 2, @connection_count
-      assert_equal 0, @timed_out
-    end
-
-    def test_pooled_connection_checkin_two
-      checkout_checkin_connections 2, 3
-      assert_equal 3, @connection_count
-      assert_equal 0, @timed_out
-    end
-
-    def test_pooled_connection_checkout_existing_first
-      ActiveRecord::Base.establish_connection(@connection.merge({:pool => 1}))
-      conn_pool = ActiveRecord::Base.connection_pool
-      conn = conn_pool.checkout
-      conn_pool.checkin(conn)
-      conn = conn_pool.checkout
-      assert ActiveRecord::ConnectionAdapters::AbstractAdapter === conn
-      conn_pool.checkin(conn)
-    end
-  end
-end

activerecord/test/cases/transactions_test.rb

@@ -296,7 +296,6 @@ def test_transaction_per_thread
               topic.approved = !topic.approved?
               topic.save!
             end
-            Topic.clear_active_connections!
           end
         end
 
@@ -332,7 +331,6 @@ def test_transaction_isolation__read_committed
               dev = Developer.find(1)
               assert_equal original_salary, dev.salary
             end
-            Developer.clear_active_connections!
           end
         end
 
@@ -344,7 +342,6 @@ def test_transaction_isolation__read_committed
               # Always expect original salary.
               assert_equal original_salary, Developer.find(1).salary
             end
-            Developer.clear_active_connections!
           end
         end