Re: getting list of objects for packing

From: Brandon Casey <casey@nrlssc.navy.mil>
Date: Oct 31, 2008, 21:40 UTC
Message-ID: <fAUegZ3bxPo8HquZjUM9syW-giYefuAzBtb1XXHQ-TwbmvJvMZvmDA@cipher.nrlssc.navy.mil>
In-Reply-To: <7v7i7o8nc5.fsf@gitster.siamese.dyndns.org>

Junio C Hamano wrote:

Show 16 quoted lines

> Brandon Casey <casey@nrlssc.navy.mil> writes:
> 
>> Nicolas Pitre wrote:
>>> On Fri, 31 Oct 2008, Brandon Casey wrote:
>>>>   -The sed statement is stripping off anything after the sha1. Any way to
>>>>    get rev-list to print out just the sha1 so that sed is not necessary?
>>> If you strip the data after the SHA1 when pipping into pack-objects then 
>>> you'll have horrible delta compression results.  The path names after 
>>> each SHA1 is used to sort objects when trying to find best matches for 
>>> delta compression. So you should preserve those and feed it back 
>>> especially with those packs that you still want delta compression for.
>> Ah, I'll have to rethink my script then. Thanks!
> 
> Yeah, but wasn't the purpose of your whole exercise to list objects that
> do not delta nor compress well with each other, in which case the delta
> compression order (aka name hash) would not matter, no?

The script I wrote actually starts up two pack-objects instances and I was writing the objects I wanted to pack _normally_ to one, and the ones that I did not want compressed/deltafied to the other (which was started with --no-reuse-object --window=0 --depth=0 --compression=0).

I didn't mentioned that fact in my first email, but I'm very glad Nico made his point.

-brandon