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From: Mike Hommey <mh@glandium.org>
To: Jon Smirl <jonsmirl@gmail.com>
Cc: Julian Phillips <julian@quantumfyre.co.uk>,
	Andreas Ericsson <ae@op5.se>, Theodore Tso <tytso@mit.edu>,
	Junio C Hamano <gitster@pobox.com>,
	Git Mailing List <git@vger.kernel.org>
Subject: Re: Git's database structure
Date: Wed, 5 Sep 2007 19:39:12 +0200	[thread overview]
Message-ID: <20070905173912.GB3396@glandium.org> (raw)
In-Reply-To: <9e4733910709050912i57ed7137o6abb02ee741d394b@mail.gmail.com>

On Wed, Sep 05, 2007 at 12:12:28PM -0400, Jon Smirl <jonsmirl@gmail.com> wrote:
> On 9/5/07, Julian Phillips <julian@quantumfyre.co.uk> wrote:
> > On Wed, 5 Sep 2007, Jon Smirl wrote:
> >
> > > On 9/5/07, Andreas Ericsson <ae@op5.se> wrote:
> > >> Jon Smirl wrote:
> > >>>
> > >>> The path name field needs to be moved back into the blobs to support
> > >>> alternative indexes. For example I want an index on the Signed-off-by
> > >>> field. I use this index to give me the SHAs for the blobs
> > >>> Signed-off-by a particular person. In the current design I have no way
> > >>> of recovering the path name for these blobs other than a brute force
> > >>> search following every path looking for the right SHA.
> > >>>
> > >>
> > >> Ah, there we go. A use-case at last :)
> >
> > But not a brilliant one.  You sign off on commits not blobs.  So you go
> > from the sign-off to paths, then to blobs.  There is no need to go from
> > blob to path unless you deliberately introduce such a need.
> 
> Use blame for an example. Blame has to crawl every commit to see if it
> touched the file. It keeps doing this until it figures out the last
> author for every line in the file. Worse case blame has to crawl every
> commit in the data store.

And why exactly would you need to change blobs to contain path for blame
to be faster ?

Or more generally, what, in the current way of git doing things,
prevents you from adding an index to $THE_DATA_YOU_LIKE, exactly ?

>From the very few use cases you've given, I see nothing preventing to
create an additional index from the data git currently uses.

Mike

  parent reply	other threads:[~2007-09-05 17:42 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-04 15:23 Git's database structure Jon Smirl
2007-09-04 15:55 ` Andreas Ericsson
2007-09-04 16:07   ` Mike Hommey
2007-09-04 16:10     ` Andreas Ericsson
2007-09-04 16:19   ` Jon Smirl
2007-09-04 16:29     ` Andreas Ericsson
2007-09-04 17:09     ` Jeff King
2007-09-04 20:17     ` David Tweed
2007-09-04 17:21   ` Junio C Hamano
2007-09-04 16:28 ` Jon Smirl
2007-09-04 16:31   ` Andreas Ericsson
2007-09-04 16:47     ` Jon Smirl
2007-09-04 16:51       ` Andreas Ericsson
2007-09-04 17:25   ` Junio C Hamano
2007-09-04 17:44     ` Jon Smirl
2007-09-04 18:04       ` Mike Hommey
2007-09-04 19:44         ` Reece Dunn
2007-09-04 18:06       ` Junio C Hamano
2007-09-04 21:25       ` Theodore Tso
2007-09-04 21:54         ` Jon Smirl
2007-09-05  7:18           ` Andreas Ericsson
2007-09-05 13:41             ` Jon Smirl
2007-09-05 14:51               ` Andreas Ericsson
2007-09-05 15:37                 ` Jon Smirl
2007-09-05 15:54                   ` Julian Phillips
2007-09-05 16:12                     ` Jon Smirl
2007-09-05 17:31                       ` Julian Phillips
2007-09-06  1:27                         ` Kyle Moffett
2007-09-05 17:39                       ` Mike Hommey [this message]
2007-09-06  8:49                       ` Andreas Ericsson
2007-09-06  9:09                         ` Junio C Hamano
2007-09-06 11:03                           ` Wincent Colaiuta
2007-09-06 12:56                       ` Johannes Schindelin
2007-09-06 18:14                         ` Steven Grimm
2007-09-07  0:33                       ` Martin Langhoff
2007-09-05 19:52               ` Andy Parkins
2007-09-04 17:19 ` Julian Phillips
2007-09-04 17:30   ` Jon Smirl
2007-09-04 18:51     ` Andreas Ericsson

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