my database had 72k annotations at the time I ran these benchmarks, here's the result:
$ python scripts/batch_bench.py conf/development-app.ini dumb
Memory summary: start
types | # objects | total size
=========== | =========== | ============
dict | 13852 | 12.46 MB
frozenset | 349 | 11.85 MB
VM: 327.29Mb