Shelve doesn't appear to restore references properly????

Muppet google.com at magicdb.com
Sun Mar 9 04:06:35 CET 2003


> A shelved object cannot share data with another shelved object.  That
> is a known and accepted limitation of shelves, and, because of how
> shelves work, is not likely to go away.

Ahhhh.... Ouch.

> Yes, you can pickle a dict.  See the cPickle module.  I daresay you
> should have done it that way from the start: unless there are too many
> muppets to fit in memory, or you need fast lookup of only a few items,
> there is not much benefit of a shelf over a pickle.  (Because the
> objects share data, the latter possibility seems unlikely to me.)

I'm assuming you mean pickle a dict of all the "muppets" then restore
that entire pickle at the start of each session?

That's probably going to be too slow: this is going to end up running
as a CGI.

> Nevertheless, you know your code better than I.  If pickling a dict
> won't do, then you can work around the limitation of shelve using the
> __getstate__ and __setstate__ methods.  I will be happy to elaborate
> if you wish.

Please. I've spent most of the evening mucking around with
__getstate__ and __setstate__ and the best I've been able to manage is
a "borg" object, where the __dict__ attributes of the various restored
objects are the same, which isn't really progress. I just can't figure
out how to actually get shared objects back from the pickle, no matter
how I try.

This is really driving me nuts!




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