[ZODB-Dev] BTree performance characteristics

[Tim Peters]

[Toby Dickenson]
> I am looking at the number of persistent objects modified by
> different OIBTree operations.
>
> I see that the number is nicely low when *adding* elements to a
> BTree. However the number is much higher when changing the value
> associated with an existing key.
>
> Are BTrees known to work this way? or do I have something wierd
> going on?

It sounds fishy to me, but there's more than one implementation of BTrees
floating around and I only know about one of them.  In that one, changing a
value associated with an existing key should mark only the leaf-level
OIBucket containing the key as modified.