Hello,
I am building a object cache in python, The cache has a maximum size and the
items have expiration dates.
At the moment I'm doing like that:
cache = {} # create dictionary
cache[ID] = (object, timestamp) # Save a tuple with the object itself and a
timestamp (from datetime.datetime.now()) under a unique object ID. This
make looking up a certain item a cheap operation (AFAIK). After looking up
my program checks if the expiration date and returns cache[ID][1] or
retrieve a new object and overwrite the one saved in the cache.
My problem now:
When len(cache) > cacheSize I need to remove the oldest objects (the ones
with the smalest timestamp). For that I need to iterate through all items
and get the oldest one: (pseudo code)
oldest = datetime.datetime.now()
for i in cache:
if i[1] < a:
id = i
n = i[0]
del cache[id]
What possible you see to optimize this lookup? Or anything else you see to
make it better?
Thanks,
Florian
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