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Re: [PATCH v4 20/21] refs: add LMDB refs storage backend

From
Duy Nguyen <pclouds@gmail.com>
Date
Feb 15, 2016, 09:57 UTC
Message-ID
<CACsJy8AkWpVERj8=ABaQ89xe=6-DRLV5KBz9_sxW8TE4LUzcQw@mail.gmail.com>
In-Reply-To
<CACsJy8CWS9E0Jb4omm4k0=kZ73w9UoHmofLFCFHUhHu53zfgYw@mail.gmail.com>
On Sun, Feb 14, 2016 at 7:04 PM, Duy Nguyen <pclouds@gmail.com> wrote:
Show 34 quoted lines
> On Sat, Feb 6, 2016 at 2:44 AM, David Turner <dturner@twopensource.com> wrote:
>> +static char *get_refdb_path(const char *base)
>> +{
>> +       static struct strbuf path_buf = STRBUF_INIT;
>> +       strbuf_reset(&path_buf);
>> +       strbuf_addf(&path_buf, "%s/refdb", base);
>> +       return path_buf.buf;
>> +}
> ...
>> +static int lmdb_init_db(struct strbuf *err, int shared)
>> +{
>> +       /*
>> +        * To create a db, all we need to do is make a directory for
>> +        * it to live in; lmdb will do the rest.
>> +        */
>> +
>> +       if (!db_path)
>> +               db_path = xstrdup(real_path(get_refdb_path(get_git_common_dir())));
>
> This works for multiple worktrees. But scripts may have harder time
> getting the path. The recommended way is "git rev-parse --git-path
> refdb" but because "refdb" is not registered in path.c:common_list[],
> that command becomes git_path("refdb") instead of
> get_refdb(get_git_... like here. And I will need to know that
> .git/refdb is _not_ per-worktree when I migrate/convert main worktree
> (it's very likely I have to go that route to solve .git/config issue
> in multi worktree).
>
> The solution is register refdb to common_list[] and you can do
> git_path("refdb") here. But then what happens when another backend is
> added? Will the new backend use the same path "refdb", or say
> "refdb.sqlite"? If all backends share the name "refdb", why can't we
> just reuse "refs" instead because the default filesystem-based backend
> is technically just another backend?

To answer myself: I forgot that there were per-worktree refs (e.g. refs/bisect). It makes me wonder if we should put per-worktree refs to lmdb as well (maybe one per worktree if we don't want to put all in one db). One of the advantages of moving away from fs-based backend is the ability to deal with case sensitivity, "nested" refs (e.g. a/b and a/b/c are both refs). With this split, I think some refs are still left behind.. Sorry if this was discussed before, I haven't followed this closely.

-- 
Duy
Previous: Duy NguyenNext: David Turner
Message 49 of 53 in “refs backend”
  1. 00/20 refs backendDavid Turner, Feb 5, 2016
  2. 01/21 refs: add a backend method structure with transaction functionsDavid Turner, Feb 5, 2016
  3. 02/21 refs: add methods for misc ref operationsDavid Turner, Feb 5, 2016
  4. Michael HaggertyFeb 11, 2016
  5. David TurnerFeb 12, 2016
  6. 03/21 refs: add methods for the ref iteratorsDavid Turner, Feb 5, 2016
  7. Michael HaggertyFeb 11, 2016
  8. David TurnerFeb 12, 2016
  9. 04/21 refs: add do_for_each_per_worktree_refDavid Turner, Feb 5, 2016
  10. 05/21 refs: add methods for reflogDavid Turner, Feb 5, 2016
  11. 06/21 refs: add method for initial ref transaction commitDavid Turner, Feb 5, 2016
  12. 07/21 refs: add method for delete_refsDavid Turner, Feb 5, 2016
  13. 08/21 refs: add methods to init refs dbDavid Turner, Feb 5, 2016
  14. Michael HaggertyFeb 11, 2016
  15. David TurnerFeb 11, 2016
  16. 09/21 refs: add method to rename refsDavid Turner, Feb 5, 2016
  17. Michael HaggertyFeb 11, 2016
  18. David TurnerFeb 11, 2016
  19. 10/21 refs: make lock genericDavid Turner, Feb 5, 2016
  20. 11/21 refs: move duplicate check to common codeDavid Turner, Feb 5, 2016
  21. 12/21 refs: allow log-only updatesDavid Turner, Feb 5, 2016
  22. Michael HaggertyFeb 11, 2016
  23. David TurnerFeb 11, 2016
  24. 13/21 refs: resolve symbolic refs firstDavid Turner, Feb 5, 2016
  25. Michael HaggertyFeb 12, 2016
  26. David TurnerFeb 18, 2016
  27. Michael HaggertyFeb 18, 2016
  28. 14/21 refs: always handle non-normal refs in files backendDavid Turner, Feb 5, 2016
  29. Michael HaggertyFeb 12, 2016
  30. David TurnerFeb 18, 2016
  31. Michael HaggertyFeb 18, 2016
  32. David TurnerFeb 18, 2016
  33. 15/21 init: allow alternate ref strorage to be set for new reposDavid Turner, Feb 5, 2016
  34. Michael HaggertyFeb 12, 2016
  35. David TurnerFeb 17, 2016
  36. Michael HaggertyFeb 18, 2016
  37. 16/21 refs: check submodules ref storage configDavid Turner, Feb 5, 2016
  38. 17/21 clone: allow ref storage backend to be set for cloneDavid Turner, Feb 5, 2016
  39. 18/21 svn: learn ref-storage argumentDavid Turner, Feb 5, 2016
  40. 19/21 refs: add register_ref_storage_backends()David Turner, Feb 5, 2016
  41. Michael HaggertyFeb 12, 2016
  42. David TurnerFeb 17, 2016
  43. 20/21 refs: add LMDB refs storage backendDavid Turner, Feb 5, 2016
  44. Michael HaggertyFeb 11, 2016
  45. David TurnerFeb 11, 2016
  46. Michael HaggertyFeb 12, 2016
  47. David TurnerFeb 13, 2016
  48. Duy NguyenFeb 14, 2016
  49. Duy NguyenFeb 15, 2016
  50. David TurnerFeb 16, 2016
  51. David TurnerFeb 17, 2016
  52. 21/21 refs: tests for lmdb backendDavid Turner, Feb 5, 2016
  53. Junio C HamanoFeb 8, 2016

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