Python docs states that uuid1 uses current time to form the uuid value. But I could not find a reference that ensures UUID1 is sequential.
>>> import uuid
>>> u1 = uuid.uuid1()
>>> u2 = uuid.uuid1()
>>> u1 < u2
True
>>>
But not always:
>>> def test(n):
... old = uuid.uuid1()
... print old
... for x in range(n):
... new = uuid.uuid1()
... if old >= new:
... print "OOops"
... break
... old = new
... print new
>>> test(1000000)
fd4ae687-3619-11e1-8801-c82a1450e52f
OOops
00000035-361a-11e1-bc9f-c82a1450e52f