statement cache for deletes working on mysql

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -490,6 +490,45 @@ def update_sql(sql, name = nil) #:nodoc:
         @connection.affected_rows
       end
 
+      def exec_delete(sql, name, binds)
+        log(sql, name, binds) do
+          result = nil
+
+          cache = {}
+          if binds.empty?
+            stmt = @connection.prepare(sql)
+          else
+            cache = @statements[sql] ||= {
+              :stmt => @connection.prepare(sql)
+            }
+            stmt = cache[:stmt]
+          end
+
+
+          begin
+            stmt.execute(*binds.map { |col, val| type_cast(val, col) })
+          rescue Mysql::Error => e
+            # Older versions of MySQL leave the prepared statement in a bad
+            # place when an error occurs.  To support older mysql versions, we
+            # need to close the statement and delete the statement from the
+            # cache.
+            stmt.close
+            @statements.delete sql
+            raise e
+          end
+
+          if metadata = stmt.result_metadata
+            metadata.free
+          end
+
+          result = stmt.affected_rows
+          stmt.free_result
+          stmt.close if binds.empty?
+
+          result
+        end
+      end
+
       def begin_db_transaction #:nodoc:
         exec_without_stmt "BEGIN"
       rescue Mysql::Error