On 20 February 2018 at 02:08, Rusty Russell <ru...@rustcorp.com.au> wrote: > Hi all, > > This consumed much of our lightning dev interop call today! But > I think we have a way forward, which is in three parts, gated by a new > feature bitpair:
We've built a prototype with a new feature bit `channel_range_queries` and the following logic: When you receive their init message and check their local features - if they set `initial_routing_sync` and `channel_range_queries` then do nothing (they will send you a `query_channel_range`) - if they set `initial_routing_sync` and not `channel_range_queries` then send your routing table (as before) - if you support `channel_range_queries` then send a `query_channel_range` message This way new and old nodes should be able to understand each other > 1. query_short_channel_id > ========================= > > 1. type: 260 (`query_short_channel_id`) > 2. data: > * [`32`:`chain_hash`] > * [`8`:`short_channel_id`] We could add a `data` field which contains zipped ids like in `reply_channel_range` so we can query several items with a single message ? > 1. type: 262 (`reply_channel_range`) > 2. data: > * [`32`:`chain_hash`] > * [`4`:`first_blocknum`] > * [`4`:`number_of_blocks`] > * [`2`:`len`] > * [`len`:`data`] We could add an additional `encoding_type` field before `data` (or it could be the first byte of `data`) > Appendix A: Encoding Sizes > ========================== > > I tried various obvious compression schemes, in increasing complexity > order (see source below, which takes stdin and spits out stdout): > > Raw = raw 8-byte stream of ordered channels. > gzip -9: gzip -9 of raw. > splitgz: all blocknums first, then all txnums, then all outnums, then > gzip -9 > delta: CVarInt encoding: > blocknum_delta,num,num*txnum_delta,num*outnum. > deltagz: delta, with gzip -9 > > Corpus 1: LN mainnet dump, 1830 channels.[1] > > Raw: 14640 bytes > gzip -9: 6717 bytes > splitgz: 6464 bytes > delta: 6624 bytes > deltagz: 4171 bytes > > Corpus 2: All P2SH outputs between blocks 508000-508999 incl, 790844 > channels.[2] > > Raw: 6326752 bytes > gzip -9: 1861710 bytes > splitgz: 964332 bytes > delta: 1655255 bytes > deltagz: 595469 bytes > > [1] http://ozlabs.org/~rusty/short_channels-mainnet.xz > [2] http://ozlabs.org/~rusty/short_channels-all-p2sh-508000-509000.xz > Impressive! _______________________________________________ Lightning-dev mailing list Lightning-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
