In an exercise of experimentation I'm seeing if I can get a uuid4 collision in less than 20,000,000.

gistfile1.txt

import sys
import uuid

ids  = set()

try:
    while True:
        id = uuid.uuid4()
        if id in ids:
            break
        ids.add(id)
        l = len(ids)
        if l % 10000 == 0:
            print l
except KeyboardInterrupt:
    pass
print len(ids)
sys.exit()