I'll try with some easy answers that won't help you much ;-)
> What makes a physical structure physical? (If I point to the same persistent
> objects from different BTrees, which one then is physical if I store them?)
The first one stored.
> Should I always use an appropriate BTree to store a big mapping? (Becuse the
> BTree isn't loaded at once)
Yes, particularly for a big flat mapping (e.g. a folder containing
many many items).
> How do indexes basically work or how they are made? (Are they also BTrees,
> so that if they are big, they won't load at once?)
Yes they are BTrees.
jean . .. .... //\\\oo///\\
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