old_contents: """Kombu transport using SQLAlchemy as the message store."""
  from __future__ import absolute_import, unicode_literals
  
  import datetime
  
  from sqlalchemy import (Column, Integer, String, Text, DateTime,
                          Sequence, Boolean, ForeignKey, SmallInteger)
  from sqlalchemy.ext.declarative import declarative_base, declared_attr
  from sqlalchemy.orm import relation
  from sqlalchemy.schema import MetaData
  
  class_registry = {}
  metadata = MetaData()
  ModelBase = declarative_base(metadata=metadata, class_registry=class_registry)
  
  
  class Queue(object):
      """The queue class."""
  
      __table_args__ = {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
  
      id = Column(Integer, Sequence('queue_id_sequence'), primary_key=True,
                  autoincrement=True)
      name = Column(String(200), unique=True)
  
      def __init__(self, name):
          self.name = name
  
      def __str__(self):
          return '<Queue({self.name})>'.format(self=self)
  
      @declared_attr
      def messages(cls):
          return relation('Message', backref='queue', lazy='noload')
  
  
  class Message(object):
      """The message class."""
  
      __table_args__ = {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
  
      id = Column(Integer, Sequence('message_id_sequence'),
                  primary_key=True, autoincrement=True)
      visible = Column(Boolean, default=True, index=True)
      sent_at = Column('timestamp', DateTime, nullable=True, index=True,
                       onupdate=datetime.datetime.now)
      payload = Column(Text, nullable=False)
      version = Column(SmallInteger, nullable=False, default=1)
  
      __mapper_args__ = {'version_id_col': version}
  
      def __init__(self, payload, queue):
          self.payload = payload
          self.queue = queue
  
      def __str__(self):
          return '<Message: {0.sent_at} {0.payload} {0.queue_id}>'.format(self)
  
      @declared_attr
      def queue_id(self):
          return Column(
              Integer,
              ForeignKey(
                  '%s.id' % class_registry['Queue'].__tablename__,
                  name='FK_kombu_message_queue'
              )
          )
  
new_contents: """Kombu transport using SQLAlchemy as the message store."""
  from __future__ import absolute_import, unicode_literals
  
  import datetime
  
  from sqlalchemy import (Column, Integer, String, Text, DateTime,
                          Sequence, Boolean, ForeignKey, SmallInteger, Index)
  from sqlalchemy.ext.declarative import declarative_base, declared_attr
  from sqlalchemy.orm import relation
  from sqlalchemy.schema import MetaData
  
  class_registry = {}
  metadata = MetaData()
  ModelBase = declarative_base(metadata=metadata, class_registry=class_registry)
  
  
  class Queue(object):
      """The queue class."""
  
      __table_args__ = {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
  
      id = Column(Integer, Sequence('queue_id_sequence'), primary_key=True,
                  autoincrement=True)
      name = Column(String(200), unique=True)
  
      def __init__(self, name):
          self.name = name
  
      def __str__(self):
          return '<Queue({self.name})>'.format(self=self)
  
      @declared_attr
      def messages(cls):
          return relation('Message', backref='queue', lazy='noload')
  
  
  class Message(object):
      """The message class."""
  
      __table_args__ = (
          Index('ix_kombu_message_timestamp_id', 'timestamp', 'id'),
          {'sqlite_autoincrement': True, 'mysql_engine': 'InnoDB'}
      )
  
      id = Column(Integer, Sequence('message_id_sequence'),
                  primary_key=True, autoincrement=True)
      visible = Column(Boolean, default=True, index=True)
      sent_at = Column('timestamp', DateTime, nullable=True, index=True,
                       onupdate=datetime.datetime.now)
      payload = Column(Text, nullable=False)
      version = Column(SmallInteger, nullable=False, default=1)
  
      __mapper_args__ = {'version_id_col': version}
  
      def __init__(self, payload, queue):
          self.payload = payload
          self.queue = queue
  
      def __str__(self):
          return '<Message: {0.sent_at} {0.payload} {0.queue_id}>'.format(self)
  
      @declared_attr
      def queue_id(self):
          return Column(
              Integer,
              ForeignKey(
                  '%s.id' % class_registry['Queue'].__tablename__,
                  name='FK_kombu_message_queue'
              )
          )
  
subject: Index in sqlalchemy transport for quick sorting (#850)