more performance work?

Robert Collins robertc at robertcollins.net
Wed Nov 7 19:03:17 GMT 2007


On Wed, 2007-11-07 at 19:47 +0100, Jelmer Vernooij wrote:


> > > * custom file-specific merging
> > This doesn't need properties - it's doable today, and I thought
> > abentley
> > had something in progress there though I may be wrong.
> Where would you specify what merge algorithm should be used for a
> particular file?

What I have in mind would use a local config or a heuristic - e.g. each
merge type can probe and decide. This is simpler as a first cut and
doesn't preclude a versioned config eventually.

> > What I'd really like to point out here is that *storage* of the data for
> > a feature is -not- why we have format bumps.
> > 
> > We have format bumps to ensure that the new /logic/ required to
> > correctly process the data of a new (or add-on-supplied) feature, is
> > present, when the data is, so that old versions don't mangle (by either
> > inaction or action) the logical state of that feature for the version
> > that introduced it.
> For all of the features specified above, I think they can all be
> advisory - in other words, it's ok if the data is present but ignored by
> older versions of bzr. For example, for line endings, it's the advised
> format in which the data should be stored. 

Well, for line endings, I think its a disastrous idea to store differing
versions commit after commit - very much not advisory. History size will
grow ridiculously, and diff will not DTRT if it is advisory.

> > file properties as a way to consolidate/reduce duplication of effort in
> > the serialisation of data are a fine thing. But they *don't reduce
> > format bumps at all*.
> This means there are a lot of format bumps ahead (presumably watershed
> upgrades?).

Lots of features which can only come in on format bumps. Watersheds
should only occur when a feature has been used in a tree - until then
exporting to a down level repository should be possible. (Rich roots
hasn't been done this way, but I don't think this applies to the other
features we listed).

-Rob
-- 
GPG key available at: <http://www.robertcollins.net/keys.txt>.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20071108/c7025227/attachment.pgp 


More information about the bazaar mailing list