Implement savepoints.

6 files changed, 53 insertions, 14 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index 97c6cd4331..f23fe5a90c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -55,12 +55,14 @@ module ActiveRecord
       end
 
       # Wrap a block in a transaction.  Returns result of block.
-      def transaction(start_db_transaction = true)
+      def transaction(start_db_transaction = false)
+        start_db_transaction ||= open_transactions.zero? || (open_transactions == 1 && transactional_fixtures)
         transaction_open = false
         begin
           if block_given?
             if start_db_transaction
-              begin_db_transaction
+              open_transactions.zero? ? begin_db_transaction : create_savepoint
+              increment_open_transactions
               transaction_open = true
             end
             yield
@@ -68,21 +70,23 @@ module ActiveRecord
         rescue Exception => database_transaction_rollback
           if transaction_open
             transaction_open = false
-            rollback_db_transaction
+            decrement_open_transactions
+            open_transactions.zero? ? rollback_db_transaction : rollback_to_savepoint
           end
           raise unless database_transaction_rollback.is_a? ActiveRecord::Rollback
         end
       ensure
         if transaction_open
+          decrement_open_transactions
           begin
-            commit_db_transaction
+            open_transactions.zero? ? commit_db_transaction : release_savepoint
           rescue Exception => database_transaction_rollback
-            rollback_db_transaction
+            open_transactions.zero? ? rollback_db_transaction : rollback_to_savepoint
             raise
           end
         end
       end
-
+      
       # Begins the transaction (and turns off auto-committing).
       def begin_db_transaction()    end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index c5183357a1..cb5c5740c3 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -159,6 +159,21 @@ module ActiveRecord
       def decrement_open_transactions
         @open_transactions -= 1
       end
+      
+      def create_savepoint
+      end
+      
+      def rollback_to_savepoint
+      end
+      
+      def release_savepoint
+      end
+      
+      def current_savepoint_name
+        "rails_savepoint_#{open_transactions}"
+      end
+      
+      attr_accessor :transactional_fixtures
 
       def log_info(sql, name, seconds)
         if @logger && @logger.debug?
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 1e452ae88a..721b365bc7 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -343,6 +343,17 @@ module ActiveRecord
         # Transactions aren't supported
       end
 
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
 
       def add_limit_offset!(sql, options) #:nodoc:
         if limit = options[:limit]
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 60ec01b95e..f34093f0ff 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -567,6 +567,17 @@ module ActiveRecord
         end
       end
 
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint(savepoint_number)
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
 
       # SCHEMA STATEMENTS ========================================
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 114141a646..3d8b0e40a9 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -932,6 +932,7 @@ module Test #:nodoc:
           end
           ActiveRecord::Base.connection.increment_open_transactions
           ActiveRecord::Base.connection.begin_db_transaction
+          ActiveRecord::Base.connection.transactional_fixtures = true
         # Load fixtures for every test.
         else
           Fixtures.reset_cache
@@ -954,6 +955,7 @@ module Test #:nodoc:
         if use_transactional_fixtures? && ActiveRecord::Base.connection.open_transactions != 0
           ActiveRecord::Base.connection.rollback_db_transaction
           ActiveRecord::Base.connection.decrement_open_transactions
+          ActiveRecord::Base.connection.transactional_fixtures = false
         end
         ActiveRecord::Base.clear_active_connections!
       end
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 27b5aca18f..56b62474d9 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -122,14 +122,10 @@ module ActiveRecord
     # One should restart the entire transaction if a StatementError occurred.
     module ClassMethods
       # See ActiveRecord::Transactions::ClassMethods for detailed documentation.
-      def transaction(&block)
-        connection.increment_open_transactions
-
-        begin
-          connection.transaction(connection.open_transactions == 1, &block)
-        ensure
-          connection.decrement_open_transactions
-        end
+      def transaction(options = {}, &block)
+        options.assert_valid_keys :force
+        
+        connection.transaction(options[:force], &block)
       end
     end