From: Beman Dawes (bdawes_at_[hidden])
Date: 2003-12-15 09:55:29
At 02:56 AM 12/15/2003, Toon Knapen wrote:
>A few months ago there was some initial discussion about implementing a
>B-tree to handle hugh datastructures by storing parts of the B-tree on
>Could someone tell me if there is still something going in this area ?
Several years ago I implemented a B-tree for Boost, but was dissatisfied
with it so never submitted it. Some of the problems included that for a
B-tree to be efficient, it has to deviate from the Associative Container
requirements in many ways, large and small. I was afraid that would be
error-prone, and that users would be dissatisfied with the interface. The
iterator-based design also ran about twice as slow as the older
cursor-based design I had used in the past.
The availability of Boost type_traits and concept checking libraries now
probably means that usage errors can be detected at compile time, rather
than showing up as runtime crashes. The C++ committee has also resolved an
iterator issue that was a concern. The Boost iterator adaptors would be a
great help, too, and weak_ptr's might make the page cache management
If the project were restarted, I'd rethink the interface so that the
portions which look like Associative Container operations were in fact
Associative Container compliant, and the operations which behaved
differently from the Associative Containers had interfaces different from
the usual interfaces.
That's the status at the moment.
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