New toy for bzr developers: B+Tree index sketch

[Ian Clatworthy]

Robert Collins wrote:
> On Wed, 2008-07-02 at 22:28 +1000, Ian Clatworthy wrote:
> 
> 
>> Here are the performance figures from indexbench.py. OOo ...
> 
> These paint a very interesting picture. 
> 
> In summary:
> pack reading - massively faster at scanning indices which we do to
> combine two packs.
> 
> Fully random access: consistently slower. We yet to determine the cause.
> 
> Text extraction planning - consistently faster - 2 to 4 times faster.
> 
> Getting a revision history, from ~ the same to 4 times faster.
> 
> Writing - from 1/2 the speed (59725 keys) to about the same (1149504)
> - which suggests that for millions of keys the version you tested will
> be faster.

And writing has two aspects: everything and incremental. I'm guessing
commit is incremental (or ought to be). If so, the incremental write
speed is one we need more information about, yes?

What commands does Fully Random Access speed impact?

Ian C.