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Re: [PATCHv4 08/12] Teach the notes lookup code to parse notes trees with various fanout schemes

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Aug 28, 2009, 11:56 UTC
Message-ID
<alpine.DEB.1.00.0908281349270.7434@intel-tinevez-2-302>
In-Reply-To
<200908281240.13311.johan@herland.net>
Hi,
On Fri, 28 Aug 2009, Johan Herland wrote:
Show 7 quoted lines
> On Friday 28 August 2009, Johannes Schindelin wrote:
>
> > And I can easily imagine a repository that has a daily note generated 
> > by an automatic build, and no other notes.  The date-based fan-out 
> > just wastes our time here, and even hurts performance.
> 
> What about a month-based fanout?

Well, I hoped to convince you that the date-based approach is too rigid. You basically cannot adapt the optimal data layout to the available data.

(I like to think of this issue as related to storing deltas: we let Git choose relatively freely what to delta against, and do not force a delta against the parent commit like others do; I think it is pretty obvious that our approach is more powerful.)

So the simplest (yet powerful-enough) way I could imagine is to teach the reading part to accept any fan-out (but that fan-out is really only based on the object name, nothing else), and to adjust the writing/merging part such that it has a maximum bin size (i.e. it starts a new fan-out whenever a tree object contains more than a config-specifyable limit).

I was certainly not thinking of something as complicated as Huffman.

Ciao, Dscho

Previous: Johan HerlandNext: Johan Herland
Message 29 of 38 in “[PATCHv4 00/12] git notes”
  1. Johan HerlandAug 27, 2009
  2. 01/12 Introduce commit notesJohan Herland, Aug 27, 2009
  3. 02/12 Add a script to edit/inspect notesJohan Herland, Aug 27, 2009
  4. 03/12 Speed up git notes lookupJohan Herland, Aug 27, 2009
  5. 04/12 Add an expensive test for git-notesJohan Herland, Aug 27, 2009
  6. 05/12 Teach "-m <msg>" and "-F <file>" to "git notes edit"Johan Herland, Aug 27, 2009
  7. 06/12 fast-import: Add support for importing commit notesJohan Herland, Aug 27, 2009
  8. 07/12 t3302-notes-index-expensive: Speed up create_repo()Johan Herland, Aug 27, 2009
  9. 08/12 Teach the notes lookup code to parse notes trees with various fanout schemesJohan Herland, Aug 27, 2009
  10. Junio C HamanoAug 27, 2009
  11. Johan HerlandAug 27, 2009
  12. Johannes SchindelinAug 27, 2009
  13. Junio C HamanoAug 27, 2009
  14. Johannes SchindelinAug 28, 2009
  15. Junio C HamanoAug 27, 2009
  16. Shawn O. PearceAug 27, 2009
  17. Junio C HamanoAug 27, 2009
  18. Johan HerlandAug 27, 2009
  19. Jeff KingAug 27, 2009
  20. Junio C HamanoAug 28, 2009
  21. Sverre RabbelierAug 28, 2009
  22. Junio C HamanoAug 28, 2009
  23. Sverre RabbelierAug 28, 2009
  24. Junio C HamanoAug 28, 2009
  25. Sverre RabbelierAug 28, 2009
  26. Junio C HamanoAug 28, 2009
  27. Johannes SchindelinAug 28, 2009
  28. Johan HerlandAug 28, 2009
  29. Johannes SchindelinAug 28, 2009
  30. Johan HerlandAug 28, 2009
  31. Johannes SchindelinAug 27, 2009
  32. 09/12 Selftests verifying semantics when loading notes trees with various fanoutsJohan Herland, Aug 27, 2009
  33. 10/12 notes.c: Implement simple memory pooling of leaf nodesJohan Herland, Aug 27, 2009
  34. Alex RiesenAug 27, 2009
  35. Johan HerlandAug 27, 2009
  36. Johan HerlandAug 27, 2009
  37. 11/12 Add flags to get_commit_notes() to control the format of the note stringJohan Herland, Aug 27, 2009
  38. 12/12 Add '%N'-format for pretty-printing commit notesJohan Herland, Aug 27, 2009

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