title: Is SQLAlchemy ORM the right choice for larga data?
body: <p>I'm developing a web application where at some point, I need to select 1.000.000 rows from my database.</p>
  
  <p>My script looks like this : </p>
  
  <pre><code>engine = create_engine(
               "mysql://:@localhost/test",
               isolation_level="READ UNCOMMITTED",echo=False
          )
  
  meta = MetaData(bind=engine)
  meta.reflect(bind=engine)
  
  
  cr =  meta.tables['cr']
  bl = meta.tables['bl']
  
  DBSession = scoped_session(
      sessionmaker(
          autoflush=True,
         autocommit=False,
           bind=engine
      )
  )
  
  test_query = session.query(bl,cr).filter(bl.c.severity_logged == '4_minor')
  print test_query.all()
  </code></pre>
  
  <p>It keeps scanning the disc and increasing the memory usage but doesn't show anything.</p>
  
  <p>In MySQL command, the result is returned in 4 seconds.
  How can I use SQLALchemy to retrieve large amounts of data?</p>