On Thu, May 1, 2014 at 4:17 AM, Roger Dingledine arma@mit.edu wrote:
On Thu, May 01, 2014 at 10:02:30AM +0200, Daniel Martà wrote:
- Regarding their size, #140 suggests that they are not useful past 16 hours. I thought we could compare the compressed size of the diffs when creating them, since they may be of use for a longer time. We could do this relative size limit first as well as the time limit mentioned above.
That is all that we came up with for now, what do you think? Ideas about what might be missing or needing an update are welcome, of course :)
Hypothesis: a good chunk of the new lines are lines that you've already seen in some recent consensus. That is, they're relays that lost the Running flag but now they have it again.
Step zero, see to what extent this theory is true in practice.
If it's true a lot, is there something clients can do to take advantage of this fact? Like, keep several recent consensuses so they already have the lines they're told to add back in? Or do the numbers work out poorly here, since the bytes we spend saying "yes, those lines from back then, the ones that hash to H" eat too much into our savings to warrant the extra complexity?
One alternative in this case would be to include non-running relays in the consensus. This would make each individual consensus longer, but (if your guess is right) might make compressed diffs shorter.