I'll note that if you have the choice, you can use UUIDType rather than
LexicalUUIDType. UUIDType fixes that behavior and use a proper lexical
comparison for non-type-1 uuids (the other behavior of UUIDType is that
for type 1 uuid, it compares them by time first, i.e. it is equivalent
to TimeUUIDType for type 1 uuid).
That's super helpful, thanks!
Follow-up question: it seems that range queries on the *second* field of
a CompositeType(UUIDType(), UUIDType()) do not work.
What am I missing?
I thought that creating 1000 column names with the *same* UUID in the
first field of the CompositeType and a random UUID in the second field
would make it so I can get out four subranges of the second UUID by
constructing four evenly spaced start/finish keys -- see below.
Instead, it appears that all of the rows end up in the last subrange.
See assert below marked "this fails"
Advice on this much appreciated -- jrf
sm = SystemManager(chosen_server)
sm.create_keyspace(namespace, SIMPLE_STRATEGY, {'replication_factor': '1'})
family = 'test'
sm.create_column_family(
namespace, family, super=False,
key_validation_class = ASCII_TYPE,
default_validation_class = BYTES_TYPE,
comparator_type=CompositeType(UUIDType(), UUIDType()),
)
pool = ConnectionPool(namespace, config['storage_addresses'],
max_retries=1000, pool_timeout=10, pool_size=2,
timeout=120)
cf = pycassa.ColumnFamily(pool, family)
u1, u2, u3, u4 = uuid.uuid1(), uuid.uuid1(), uuid.uuid1(), uuid.uuid1()
cf.insert('inbound', {(u1, u2): b''})
cf.insert('inbound', {(u1, u3): b''})
cf.insert('inbound', {(u1, u4): b''})
## test range searching
start = uuid.UUID(int=u3.int - 1)
finish = uuid.UUID(int=u3.int + 1)
assert start.int < u3.int < finish.int
rec3 = cf.get('inbound',
column_start =(u1, start),
column_finish=(u1, finish)).items()
assert len(rec3) == 1
assert rec3[0][0][1] == u3
#### This assert above passes!
#### This next part fails :-/
## now insert many rows -- enough that some should fall in each
## subrange below
for i in xrange(1000):
cf.insert('inbound', {(u1, uuid.uuid4()): b''})
## do four ranges, and expect more than zero in each
step_size = 2**(128 - 2)
## go in reverse order to illustrate that they are all at the end!!!?
for i in range(2**2, 0, -1):
start = uuid.UUID(int=(i-1) * step_size)
finish = uuid.UUID(int=min(i * step_size, 2**128 - 1))
recs = cf.get('inbound',
column_start =(u1, start),
column_finish=(u1, finish)).items()
for key, val in recs:
assert val == b''
assert start < key[1] < finish ## this fails!!
assert len(recs) > 0
print len(recs), ' for ', start, finish
sm.close()
