bzr-sax actually uses xml.sax interface

[John Arbash Meinel]

Robert Collins wrote:
> On Fri, 2005-10-21 at 00:47 -0500, John A Meinel wrote:
> 
> 
>>Using the same code bases, I developed this plot:
>>http://bzr.arbash-meinel.com/other/timing-2/TimeRevstore2Weave.png
>>
>>In it, you can see that the "real sax" is negligably slower than the
>>iterparse (using cElementTree) version. While bzr.dev is much slower.
>>This is mostly because I've reformatted the revision xml to make it
>>create better weaves (as my other posts indicated).
>>
>>So I would have to say our #1 priority is to get the Weave objects faster.
>>
>>Is there interest in having some compiled C extensions, for handling the
>>performance critical portions? Python distutils has decent support for
>>that sort of thing, it means people would need to do "python setup
>>install" before using bzr, rather than just having all python code. But
>>it seems like we have a couple of very obvious performance areas. Though
>>perhaps the append-only weave would fix some of it, I'm not convinced
>>that it would.
>>Mostly because for a lot of texts, (especially inventory) you are pretty
>>likely to have lines that cross lots of revisions. So when you extract
>>them, you are still going to have to go way back in the file, and
>>rebuild the current text from a lot of previous chunks.
> 
> 
> 'setup.py build' will build such extensions without installing them,
> FWIW.
> 
> Yes, there is definite interest in C extensions for performance critical
> areas. Martin and I have discussed this quite a few times :). I think
> both of us would like to leave heavy performance optimisation until we
> are really feature complete - its much easier to mutate design in pure
> python.

I certainly agree that it is easier to mutate in python. And as I said,
it depends how pieces change. I guess I'm not really sure what the
current roadmap is. Though I'm guessing it might become clearer at UBZ.

John
=:->

> 
> Rob
> 

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