Optimize Pickle Serialization Format #54
Description
Using diskcache 2.9.0, via python 2.7 on Mac:
I am having problems using a tuple of strings as a cache key. Once the key has been placed into the cache and is subsequently retrieved from the cache via the key iterator, it apparently no longer matches the pickled form of the key when it was first inserted, leading to the value not being found when looked up in sqlite. I have tried changing the pickle format version to no avail. Using a list instead of a tuple works properly. Here is code to demonstrate the problem:
from diskcache import Cache, Index
import shutil
import tempfile
key_part_0 = u"part0"
key_part_1 = u"part1"
to_test = [
(key_part_0, key_part_1),
[key_part_0, key_part_1]
]
for key in to_test:
tmpdir = tempfile.mkdtemp(prefix="discache_test.")
try:
dc = Index.fromcache(Cache(tmpdir, eviction_policy='none', size_limit=2**32)) #4GB
dc[key] = {
"example0": ["value0"]
}
diskcache_key = dc.keys()[0]
print "Keys equal: %s" % (diskcache_key==key)
print "Value using original key: %s" % dc[key]
try:
print "Value using retrieved key: %s" % dc[diskcache_key]
except KeyError as e:
print "Could not find value using retrieved key"
finally:
shutil.rmtree(tmpdir, True)
And the output:
Keys equal: True
Value using original key: {'example0': ['value0']}
Could not find value using retrieved key
Keys equal: True
Value using original key: {'example0': ['value0']}
Value using retrieved key: {'example0': ['value0']}
Thanks for any assistance you can provide.