Re: Subversion performance (issue #1429 et al)

cmpilato@collab.net writes:

> I'll take some time to see who all uses svn_fs_dir_entries(), and how
> they use it, and determine if this change would be Goodness or not.
> If Goodness, I'll code the change and commit.

Oh, geez, there are only a couple of uses where the caller doesn't
loop over the entries calling is_dir() on every one. I'll making
coding this change my highest priority, Sander.

For the record, here's how the cost trade-off will be.

Today:

   svn_fs_dir_entries() uses the not-cheap open_path() routine to walk
   the DAG down to the directory, then reads the dirents list from the
   reps/strings data and returns it.

   svn_fs_is_dir/file() use the not-cheap open_path() routine to walk
   the DAG down to the dir/file, then reads the kind out of its
   node-revision record, and returns an answer.

Tomorrow:

   svn_fs_dir_entries() uses the not-cheap open_path() routine to walk
   the DAG down to the directory, then reads the dirents list from the
   reps/strings data, then opens each dirent directly and asks the
   kind question, then returns the dirents with their kinds. Note
   that no open_path() is needed here because we already have the
   node-rev-ids of the entries. In other words, this is *far* cheaper
   to do inside the API than the equivalent work outside the API.

   svn_fs_is_dir/file() is not changed, but isn't called *nearly* as
   often. :-)

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Received on Sun Aug 17 17:16:30 2003