title: SQLAlchemy Core bulk insert slow
body: <p>I'm trying to truncate a table and insert only ~3000 rows of data using SQLAlchemy, and it's very slow (~10 minutes). </p>
  
  <p>I followed the recommendations on this <a href="http://docs.sqlalchemy.org/en/latest/faq/performance.html" rel="nofollow">doc</a> and leveraged sqlalchemy core to do my inserts, but it's still running very very slow. What are possible culprits for me to look at? Database is a postgres RDS instance. Thanks!</p>
  
  <pre><code>engine = sa.create_engine(db_string, **kwargs, pool_recycle=3600)
  with engine.begin() as conn:
              conn.execute("TRUNCATE my_table")
              conn.execute(
                  MyTable.__table__.insert(),
                  data #where data is a list of dicts
              )
  </code></pre>