Remove CachedConnectionPerThread per-thread pooling mechanism in favor of a fixed pool with default maximum of 5 connections

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

@@ -36,12 +36,10 @@ module ActiveRecord
       # * +wait_timeout+ (optional): number of seconds to block and wait
       #   for a connection before giving up and raising a timeout error.
       def self.create(spec)
-        if spec.config[:pool] && spec.config[:pool].to_i > 0
-          FixedSizeConnectionPool.new(spec)
-        elsif spec.config[:jndi] # JRuby appserver datasource pool; passthrough
+        if spec.config[:jndi] # JRuby appserver datasource pool; passthrough
           NewConnectionEveryTime.new(spec)
         else
-          CachedConnectionPerThread.new(spec)
+          FixedSizeConnectionPool.new(spec)
         end
       end
 
@@ -204,18 +202,6 @@ module ActiveRecord
       end
     end
 
-    # CachedConnectionPerThread is a compatible pseudo-connection pool that
-    # caches connections per-thread. In order to hold onto threads in the same
-    # manner as ActiveRecord 2.1 and earlier, it only disconnects the
-    # connection when the connection is checked in, or when calling
-    # ActiveRecord::Base.clear_all_connections!, and not during
-    # #release_connection.
-    class CachedConnectionPerThread < NewConnectionEveryTime
-      def release_connection
-        # no-op; keep the connection
-      end
-    end
-
     # FixedSizeConnectionPool provides a full, fixed-size connection pool with
     # timed waits when the pool is exhausted.
     class FixedSizeConnectionPool < ConnectionPool
@@ -223,7 +209,8 @@ module ActiveRecord
         super
         # default 5 second timeout
         @timeout = spec.config[:wait_timeout] || 5
-        @size = spec.config[:pool].to_i
+        # default max pool size to 5
+        @size = (spec.config[:pool] && spec.config[:pool].to_i) || 5
         @queue = @connection_mutex.new_cond
         @connections = []
         @checked_out = []

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -285,6 +285,7 @@ module ActiveRecord
           # See http://bugs.mysql.com/bug.php?id=33540 -- the workaround way to
           # reset the connection is to change the user to the same user.
           @connection.change_user(@config[:username], @config[:password], @config[:database])
+          configure_connection
         else
           super
         end
@@ -538,7 +539,11 @@ module ActiveRecord
           end
 
           @connection.real_connect(*@connection_options)
+          configure_connection
+        end
 
+        def configure_connection
+          encoding = @config[:encoding]
           execute("SET NAMES '#{encoding}'") if encoding
 
           # By default, MySQL 'where id is null' selects the last inserted id.

activerecord/lib/active_record/fixtures.rb

@@ -955,7 +955,7 @@ module Test #:nodoc:
           ActiveRecord::Base.connection.rollback_db_transaction
           ActiveRecord::Base.connection.decrement_open_transactions
         end
-        ActiveRecord::Base.verify_active_connections!
+        ActiveRecord::Base.clear_active_connections!
       end
 
       private

activerecord/test/cases/locking_test.rb

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

activerecord/test/cases/threaded_connections_test.rb

@@ -16,12 +16,14 @@ unless %w(FrontBase).include? ActiveRecord::Base.connection.adapter_name
 
   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/test/cases/transactions_test.rb

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