[ZODB-Dev] Re: [Zope3-dev] Re: Community opinion about search+filter

[Jim Washington]

Hi, Martijn

I have a suggestion, only because I have played around with the idea a bit.

Google for "python factoradics", and you will get my blog entry about
factoradics.

I see the problem statement as "How to obtain batching without
re-sorting multiple times".

If you see a sort order as one permutation of a list, the factoradic
technique provides a key to that permutation.  So, in theory, one would
sort the list, and store the factoradic index for that permutation.  The
next time the particular sort order is requested, it's a simple matter
of unpacking the factoradic. I have not done any tests to see whether
unpacking a factoradic is significantly less expensive than re-sorting. 
Intuitively, it should be.  In practice, I am not so sure.

Anyway, this is FWIW.  :)

-Jim Washington