Hyrum K Wright wrote on Fri, Jul 01, 2011 at 11:21:58 -0500: > On Fri, Jul 1, 2011 at 8:05 AM, Daniel Shahaf <danie...@elego.de> wrote: > > Hyrum K Wright wrote on Thu, Jun 30, 2011 at 16:33:16 -0500: > >> On Thu, Jun 30, 2011 at 3:27 PM, Peter Samuelson <pe...@p12n.org> wrote: > >> > > >> > [Ivan Zhakov] > >> >> It should be easy to implement editing revprops without using SQLite: > >> >> in case someone modify revprop non-packed revprop file is created, in > >> >> read operation non-packed revprop file should be considered as more > >> >> up-to-date. In next svnadmin pack operation these non-packed files > >> >> should be merged back to packed one. > >> > > >> > +1. This would basically mean there's only _one_ code path for writing > >> > revprops, yes? 'svnadmin pack' gets a little more complex, but the > >> > rest of libsvn_fs_fs gets simpler. > >> > > >> > Anyone have time to actually do this? Converting the packed format > >> > from sqlite to the same format used for packed revs would be a bonus. > >> > >> I like this idea, but it would seem to introduce an additional stat() > >> call* for every attempt to fetch a revprop, because you'd first have > >> to check the "old" location, and then the packed one. > > > > I don't like the idea of writing revprops outside the DB and moving them > > back in. (I think I already said why elsethread?) > > (I will assume "the DB" means "the SQLite-backed revprop database".) > > I agree with you, but I don't think that's what the proposal was > about. My understanding would be that we'd pack revprops just like we > pack revision (one single concat'd file per shard), and then store any > edits in separate files. We'd then "repack" the edits into the pack > files when an admin subsequently runs 'svnadmin pack'.
Yes, that's exactly what I don't like :-) I already outlined one case where I think the behaviour would be incorrect. (And even stefan2's suggestion from IRC yesterday doesn't solve that race condition --- unless we can depend on the OS providing an atomic unlink_if_timestamp_is_not_X() functionality) > Aside from the complexity of having to attempt to open the non-packed > file everywhere before failing through to the common case, I really > like this solution. (So much so that I may go implement it...) As I said on #3944, I plan to implement the suggestion of "Either all revprops are in sharded files, or all revprops are in the DB" (due to Peter). So, let's agree on /what/ behaviour we want to implement, before either of us goes and implements anything :-) > > -Hyrum
