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Re: [RFC/PATCH 0/8] Add configuration options for split-index

From
Duy Nguyen <pclouds@gmail.com>
Date
Jul 25, 2016, 16:04 UTC
Message-ID
<CACsJy8DRmcUzG+Uj65nqmyjbohbWq1Us4c7YkNkG15fjGijfEA@mail.gmail.com>
In-Reply-To
<CAP8UFD20WtCPLb3VzCJnYZSreUM7Q8GOC_VBG3h1j3wjOcR=_w@mail.gmail.com>

On Sat, Jul 23, 2016 at 6:11 PM, Christian Couder <christian.couder@gmail.com> wrote:

Show 12 quoted lines
> Ok, I started working on automatically pushing back all changes to the
> shared index when the percentage of entries in linked vs shared
> indexes is greater than 25% (maybe I will make it configurable later).
> It is very basic and doesn't work well for now (for one thing it is
> missing added entries), see:
>
> https://github.com/chriscool/git/commits/config-split-index8
>
> Basically I would like a way to count then entries that are only in
> the linked index without modifying them to be safe, but I have a hard
> time seeing how I could modify prepare_to_write_split_index() to get
> that.

Hmm.. can you do the counting separately? A shared cache_entry must have its field "index" greater than zero. By counting the number of entries whose index is zero (i.e. not shared) against the total number of real (*) entries, you should have a decent estimate when to split. Then you can do exactly what "git update-index --no-split-index" and "git update-index --split-index" sequence does, but in write_index(). It's easier than messing inside split-index.c. If we hit performance problem, then we can look into changing split-index.c

(*) remember that some entries may be marked CE_REMOVE, which are dead entries and should not be counted because they will never be written down on disk.

-- 
Duy
Previous: Christian CouderNext: Christian Couder
Message 18 of 19 in “Add configuration options for split-index”
  1. 0/8 Add configuration options for split-indexChristian Couder, Jul 11, 2016
  2. 2/8 split-index: add {add,remove}_split_index() functionsChristian Couder, Jul 11, 2016
  3. 3/8 read-cache: add and then use tweak_split_index()Christian Couder, Jul 11, 2016
  4. 5/8 Documentation/config: add information for core.splitIndexChristian Couder, Jul 11, 2016
  5. 6/8 Documentation/git-update-index: talk about core.splitIndex config varChristian Couder, Jul 11, 2016
  6. 7/8 t1700: add tests for core.splitIndexChristian Couder, Jul 11, 2016
  7. 4/8 update-index: warn in case of split-index incoherencyChristian Couder, Jul 11, 2016
  8. 8/8 read-cache: unlink old sharedindex filesChristian Couder, Jul 11, 2016
  9. Duy NguyenJul 11, 2016
  10. Christian CouderJul 12, 2016
  11. Duy NguyenJul 12, 2016
  12. Christian CouderJul 12, 2016
  13. Duy NguyenJul 13, 2016
  14. Christian CouderJul 13, 2016
  15. 1/8 config: add git_config_get_split_index()Christian Couder, Jul 11, 2016
  16. Duy NguyenJul 12, 2016
  17. Christian CouderJul 23, 2016
  18. Duy NguyenJul 25, 2016
  19. Christian CouderJul 25, 2016

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