Date: Sun, 30 Oct 2022 12:40:14 +1000
From: Anthony Towns <aj@erisian.com.au>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] On mempool policy consistency
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On Sun, Oct 30, 2022 at 11:02:43AM +1000, Anthony Towns via bitcoin-dev wrote:
> > Some napkin math: there are about 250,000 transactions a day; if
> > we round that up to 100 million a year and assume we only want one
> > transaction per year to fail to initially propagate on a network where
> > 30% of nodes have adopted a more permissive policy, lightweight clients
> > will need to connect to over 50 randomly selected nodes.[1]  
> A target failure probability of 1-in-1e8 means:

Oh, based on the "receive version message" log entries of a node that
only does outbound connections, over the last ~3 weeks I see about 3000
outbound connections (mostly feelers/block-relay-only ones), of which
a bunch identify as non-taproot supporting:

     10 /Satoshi:0.16.0/:
     13 /Satoshi:0.17.0/:
     13 /Satoshi:0.17.0.1/:
     28 /Satoshi:0.16.3/:
     29 /Satoshi:0.19.0.1/:
     36 /Satoshi:0.18.1/:
     37 /Satoshi:0.19.1/:
     39 /Satoshi:0.17.1/:
     50 /Satoshi:0.20.0/:
     94 /Satoshi:0.21.0/:
     95 /Satoshi:0.18.0/:
    244 /Satoshi:0.20.1/:

Those add up to 688+ of 3065 total; if that's representative, it
presumably means a random node connecting to 8 random listening peers has
a 6.44-in-1-million chance of only connecting to peers that don't support
taproot, ie failing your suggested threshold by a factor of about 644.

Cheers,
aj