On 17 December 2010 09:54, Tad Glines <[email protected]> wrote: > This proposal does present one solution to a problem I hadn't yet resolved > which was how to deal efficiently with the commit notice and acknowledgement > data. Logically the data is represented as records with four fields > (Destination name, WaveletName, last acknowledged version, last committed > version). Another way to look at is as a sparse table where the first two > columns are WaveletName and last committed version and the remaining columns > contain the last acknowledged version for a given name, one name per column. > > I think it's possible to generate checkpoints from the DeltaStore without > too much change. For the fileDeltaStore, the DeltaAccess implementation > would append a (WaveletName, start version, end version) record to a file > (at the root of the store), and an timer job (triggered by the first log > append) would suck in all the records, merge them and generate a checkpoint. > This would allow the DeltaStore to generate checkpoints without the need to > change it's existing interface and only minor changes to it's > implementation. > > I'm assuming that SignedVersion is actually HashedVersion. And that the > structure of CheckPoint a sequence of triples {wavelet name, start version, > end version}). I'm also assuming that CheckpointId's have a natural order > and monotonically increase. >
All correct assumptions. > > I think some of the details of the interfaces need to be changed but > fundamentally it seems like an appropriate solution for WiaB. > > -Tad > > On Thu, Dec 16, 2010 at 1:59 PM, Alex North <[email protected]> wrote: > >> Oops, thanks, I had hotlinked a non-internet-accessible images. >> >> Also +wave-dev >> >> >> On 17 December 2010 02:14, Tad Glines <[email protected]> wrote: >> >>> The image is broken. >>> >>> On Wed, Dec 15, 2010 at 9:51 PM, Alex North <[email protected]> wrote: >>> >>>> Prompted by Tad's proposal for commit notification persistence I've got >>>> around to publishing a design we had in Google Wave, and were part way >>>> through implementing (we can probably open the code) for a recovery service >>>> based on checkpoint messages. >>>> >>>> >>>> https://sites.google.com/a/waveprotocol.org/wave-protocol/protocol/design-proposals/checkpoint-based-recovery >>>> >>>> This has many similarities with Tad's proposal and aims to solve the >>>> same problems. Note that this design was originally for Google Wave, and >>>> Wave in a Box may support an even simpler design to start. This is a good >>>> opportunity to review the design (though since there is existing code this >>>> may be a good place to start). >>>> >>>> Alex >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Wave Protocol" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]<wave-protocol%[email protected]> >>>> . >>>> For more options, visit this group at >>>> http://groups.google.com/group/wave-protocol?hl=en. >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Wave Protocol" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]<wave-protocol%[email protected]> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/wave-protocol?hl=en. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Wave Protocol" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<wave-protocol%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/wave-protocol?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Wave Protocol" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<wave-protocol%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/wave-protocol?hl=en. > -- You received this message because you are subscribed to the Google Groups "Wave Protocol" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/wave-protocol?hl=en.
