diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 377f2a44c5a01232e196e11203d24dfd5df6c9dc..bf8c546d2e45f361063af4704ffb3a931fdbab4d 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -56,7 +56,7 @@ module ConnectionAdapters
     # * +wait_timeout+: number of seconds to block and wait for a connection
     #   before giving up and raising a timeout error (default 5 seconds).
     class ConnectionPool
-      attr_reader :spec
+      attr_reader :spec, :connections
 
       # Creates a new ConnectionPool object. +spec+ is a ConnectionSpecification
       # object which describes database connection information (e.g. adapter,
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index fa28bc64dfc5721f2b4db0b16d932a25304557c4..8c0bf6396a31f7fd9baaf600077a84f7908bc997 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -579,6 +579,8 @@ def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
       protected
 
         def translate_exception(exception, message)
+          return super unless exception.respond_to?(:errno)
+
           case exception.errno
           when 1062
             RecordNotUnique.new(message, exception)
diff --git a/activerecord/test/cases/pooled_connections_test.rb b/activerecord/test/cases/pooled_connections_test.rb
index 2529a33dab2670eb1dbd2119554cda06092c88f0..4e54079ba59110488058267e85840a4a2af7fa26 100644
--- a/activerecord/test/cases/pooled_connections_test.rb
+++ b/activerecord/test/cases/pooled_connections_test.rb
@@ -61,12 +61,14 @@ def test_pooled_connection_checkin_one
     checkout_checkin_connections 1, 2
     assert_equal 2, @connection_count
     assert_equal 0, @timed_out
+    assert_equal 1, ActiveRecord::Base.connection_pool.connections.size
   end
 
   def test_pooled_connection_checkin_two
     checkout_checkin_connections 2, 3
     assert_equal 3, @connection_count
     assert_equal 0, @timed_out
+    assert_equal 1, ActiveRecord::Base.connection_pool.connections.size
   end
 
   def test_pooled_connection_checkout_existing_first