Is there an application that requires watching for output scripts that doesn't also require watching for input scrips (or, less efficiently, input outpoints)?
Any of the wallet application that I'm aware of need to see coins being spent as well as created, else they may try to spend already spent coins. If we're not aware of any applications that wouldnt use both, there isn't much reason to separate them and if input scripts are used instead of input outpoints there is additional savings from combining them (due to the same scripts being spent as were created in the block-- due to reuse and chaining). I still am of the belief, based on Matt's argument, that there is no use for txid what-so-ever (instead just watch for an outpoint). On Mon, May 28, 2018 at 6:28 PM, Tamas Blummer <tamas.blum...@gmail.com> wrote: > Forgot to mention: The link I sent is to a branch that is patched to produce > the filter stats. > This is the main project and the BIP158 implementation: > https://github.com/rust-bitcoin/rust-bitcoin-spv/blob/master/src/blockfilter.rs > > Tamas Blummer > >> On May 28, 2018, at 20:18, Tamas Blummer <tamas.blum...@gmail.com> wrote: >> >> Hi Jim, >> >> A “basic” combined filter would mean up to 0.5 GB filter data per month >> (with 100% segwith use). Considering that 1 GB is the usual data quota for >> an entry level mobile phone contract, this could be a too high barrier for >> adoption. >> >> I repeated your calculations and produced a slightly different graph that >> shows the fraction of cummulative filter size to cummulative blockchain >> size. This is less noisy but otherwise confirms your measurement. >> >> I think that the data supports separation of filters as a combined filter >> does not seem to come with significant savings. (basic size ~= txid + input >> points + output scripts sizes) >> >> My calculations are repeatable with: >> >> https://github.com/tamasblummer/rust-bitcoin-spv/blob/blockfilterstats/src/bin/blockfilterstats.rs >> >> that is using a Rust implementation of an SPV client built on top of other >> libraries we work on in the rust-bitcoin GitHub community >> (https://github.com/rust-bitcoin). Yes, this is a shameles plug for the >> project hoping to attract more developer. >> >> Tamas Blummer >> >> >> <filters.png> >> >>> On May 24, 2018, at 05:48, Jim Posen via bitcoin-dev >>> <bitcoin-dev@lists.linuxfoundation.org> wrote: >>> >>> Greg, I've attached a graph including the input scripts. >>> >>> In the top graph, we can see how the input script filter compares to the >>> input outpoint filter. It is definitely smaller as a result of address >>> reuse. The bottom graph shows the ratio over time of combining the input >>> prev script and output script filters vs keeping them separate. In more >>> recent blocks, it appears that there are decreasing savings. >>> >> > _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
