Greg Stein wrote on Thu, Apr 26, 2012 at 14:01:24 -0400:
> On Apr 26, 2012 1:56 PM, "Daniel Shahaf" <danielsh_at_elego.de> wrote:
> >
> > Greg Stein wrote on Thu, Apr 26, 2012 at 13:29:55 -0400:
> > > On Apr 26, 2012 12:55 PM, "Daniel Shahaf" <danielsh_at_elego.de> wrote:
> > > >
> > > > danielsh_at_apache.org wrote on Thu, Apr 26, 2012 at 16:30:45 -0000:
> > > > > Author: danielsh
> > > > > Date: Thu Apr 26 16:30:44 2012
> > > > > New Revision: 1330932
> > > > >
> > > > > URL: http://svn.apache.org/viewvc?rev=1330932&view=rev
> > > > > Log:
> > > > > Follow-up to r1330906: fix/work-around trail reentrancy assertions
> in
> > > BDB.
> > > > >
> > > > > (Why is the uuid stored in svn_fs_t->fsap_data rather than in
> svn_fs_t
> > > proper?)
> > > > >
> > > > > * subversion/libsvn_fs/fs-loader.c
> > > > > (cache_uuid): New function.
> > > > > (svn_fs_open, svn_fs_create): Call it after everything else.
> > > > > (svn_fs_open_berkeley, svn_fs_create_berkeley): Ditto.
> > > >
> > > > The purpose of this is to cause UUID to be cached in BDB's
> > > > svn_fs_t->fsap_data so that the new-in-r1330906 calls to
> > > > fs->vtable->get_uuid() wouldn't provoke the "run a transaction"
> > > > codepath of svn_fs_base__get_uuid().
> > > >
> > > > That seems a bit fragile; I'm not sure whether a better fix should be
> > > > found (get the UUID within the existing trail) or whether this should
> be
> > > > documented and svn_fs_base__get_uuid() annotated to point out that the
> > > > "run a trail" codepath now only runs once at the time of opening the
> > > > svn_fs_t.
> > > >
> > > > Thoughts?
> > >
> > > Put the uuid into svn_fs_t and fill it at creation time using the
> vtable.
> > > Change svn_fs_get_uuid to return that, rather than using the vtable.
> > >
> >
> > And delete the fs_vtable_t->get_uuid and fs_vtable_t->set_uuid callbacks
> > altogether, I presume.
>
> Umm. No... don't you still need the vtable to access/set the persisted
> value?
>
No, I don't. svn_fs_set_uuid() can set a hypothetical svn_fs_t->uuid
field itself; it only needs a vtable->set_uuid() helper if it wants to
set fsap_data->uuid (which exists in both backends, but fsap_data is
opaque to libsvn_fs).
> I'm just suggesting that the vtable is used at init time, rather than every
> call to get_uuid.
>
Where do you envision the UUID stored/cached --- in svn_fs_t or in
svn_fs_t->fsap_data? I understand we move it from the latter to the
former.
> Cheers,
> -g
Received on 2012-04-26 20:28:12 CEST