Unpickling bytea columns from Psycopg2

Unpickling bytea columns from Psycopg2

I am storing pickled objects in a PostgreSQL database. Originally I
thought this was a bad idea, but they are seldom accessed and from what
I've learned apparently TOAST makes the performance impact minimal for
storing big blobs in a relational database.
When you INSERT or UPDATE a bytea column it is simple. Just construct a
psycopg2.Binary and pass it to the execute call on the cursor object. In
my case, it's a pickled object.
Whenever you do a SELECT and get back a bytea column you wind up with a
python buffer object. In other words, you can't just do a pickle.loads or
a pickle.load. The best I've come up with is using StringIO
import psycopg2
import cPickle as pickle
import cStringIO as StringIO
conn = psycopg2.connect(user='postgres',database='postgres')
cur = conn.cursor()
cur.execute('Select %s', (psycopg2.Binary(pickle.dumps({'foo':'bar'},-1)), ))
result, = cur.fetchone()
cur.close()
conn.rollback()
result = StringIO.StringIO(result)
print pickle.load(result)
What's the cost of this? Are the StringIO objects just shallow copies of
the original buffer object? Is there a more practical way of doing this?
I'm using Stackless 2.7.5 if it matters.