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Re: Using bitmaps to accelerate fetch and clone

From
Shawn Pearce <spearce@spearce.org>
Date
Oct 2, 2012, 15:00 UTC
Message-ID
<CAJo=hJtUVLpQaiR==DGdpeH5V5DGh9eF-Ez+gMNNKOyp_HbwVg@mail.gmail.com>
In-Reply-To
<CACsJy8Aikmf5vwNhLbELLKfyLLPTppWFvoqGOdSBZ2JoL1C_JQ@mail.gmail.com>
On Mon, Oct 1, 2012 at 5:48 AM, Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
> Probably off topic. Does saving a list of missing bases in the pack
> index help storing thin packs directly? I may be missing some points
> because I don't see why thin packs cannot be stored on disk in the
> first place.

Packs are supposed to be completely self contained. We require all delta bases to be in the pack so that we can always recover the objects stored within it, even if there is no other pack available. This simplifies things like git gc such that they don't need to worry about retaining delta bases for other packs, or avoiding delta chain cycles between packs. I have managed to create a A->B->A delta chain once that made the repository corrupt as soon as the last non-delta copy of A as removed. Both A and B became unreadable as A needed B which needed A which needed B... :-(

To keep things simple and easily verified as correct, we don't allow this.
Previous: Nguyen Thai Ngoc Duy
Message 20 of 20 in “Using bitmaps to accelerate fetch and clone”
  1. Shawn PearceSep 27, 2012
  2. Nguyen Thai Ngoc DuySep 27, 2012
  3. Shawn PearceSep 27, 2012
  4. Nguyen Thai Ngoc DuySep 28, 2012
  5. Jeff KingSep 27, 2012
  6. Shawn PearceSep 27, 2012
  7. Jeff KingSep 27, 2012
  8. Shawn PearceSep 27, 2012
  9. Jeff KingSep 27, 2012
  10. Jeff KingSep 27, 2012
  11. Junio C HamanoSep 27, 2012
  12. Jeff KingSep 27, 2012
  13. David Michael BarrSep 27, 2012
  14. Nguyen Thai Ngoc DuySep 28, 2012
  15. Nguyen Thai Ngoc DuySep 28, 2012
  16. Shawn PearceOct 1, 2012
  17. Nguyen Thai Ngoc DuyOct 1, 2012
  18. Shawn PearceOct 1, 2012
  19. Nguyen Thai Ngoc DuyOct 1, 2012
  20. Shawn PearceOct 2, 2012

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