[Tutor] __slots__

Liam Clarke ml.cyresse at gmail.com
Wed Oct 12 14:17:17 CEST 2005

If you've been wondering about how useful this is...

Well, all I can say is, don't use them unless you need them, they're a
lot of hassle.
I created two versions of the same object, same attribute values,  one
with slots, one without.

With slots, it pickled to a string of 163 characters. Without,
341.That's 178 bytes saved, rough approximation. So, if I create 5000
objects, I've saved somewhere around 900Kb of RAM.

At 500,000 objects I'd be saving roughly 86Mb of RAM, assuming that a
pickled object corresponds to one in memory. Or, 86Mb of HD space.

Of course, having to learn what __getstate__ was in order to pickle
the slotted instance wasn't much fun. Remember, premature optimisation
is bad...

This was a smaller object, so it'll be interesting to see what economy
an object with 70ish attributes makes. FWIW, I'm doing the exact
opposite of XP, and building to handle 300,000 to 600,000 objects...


Liam Clarke

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