[squeak-dev] Re: Our process, some loose ideas regarding DS + MC
Göran Krampe
goran at krampe.se
Sun Aug 16 11:32:25 UTC 2009
Hi!
Igor Stasenko wrote:
> 2009/8/16 Andreas Raab <andreas.raab at gmx.de>:
>> Which reminds me: Where are the deltas stored and how big is the space
>> overhead for keeping them?
>
> i think most common overhead is 2x more space comparing to analoguous
> changeset record, since you have to keep 'before' version in addition
> to 'after' version. And most common change is changing the method(s)
> source a little bit.
Well, in fact it is more - a Changeset does in fact not hold a copy of
the new method source - just a pointer to the method modified (IIRC).
Thus Changesets are sneaky beasts, most people get the wrong impression.
> Oh, and did Goran mentioned that Deltas could be also 'compressed' in
> same way as changeset?
Yes, I have called it "normalized" but compressed may be a better term.
That code is not yet finished though, but a fun coding task for anyone
interested. :) There are two scenarios:
- Compressing a single Delta into its non redundant form. This makes it
look like a Changeset. Before compression it is a "perfect" log.
- Compression of multiple Deltas into one. This one is trivial once you
implemented first one.
For bug fixes and patches I believe one would naturally want to compress
before distributing of course.
regards, Göran
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