Date: Thu, 20 Jan 2022 21:22:15 -0500
From: Peter Todd <pete@petertodd.org>
To: Bram Cohen <bram@chia.net>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Message-ID: <YeoY12X1skxA8Lcy@petertodd.org>
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Cc: Billy Tetrud <billy.tetrud@gmail.com>
Subject: Re: [bitcoin-dev] Covenants and capabilities in the UTXO model
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On Thu, Jan 20, 2022 at 11:23:30AM -0800, Bram Cohen via bitcoin-dev wrote:
> > Nodes currently aren't required to keep around the whole blockchain, but
> > your proposal sounds like it would require them to. I think this could =
be
> > pretty detrimental to future scalability. Monero, for example, has a
> > situation where its UTXO set is the whole blockchain because you can't
> > generally know what has been spent and what hasn't been. Allowing
> > references to old blocks would pull in all this old block data into the
> > UTXO set. So unless you're very careful about how or when you can refer=
ence
> > old blocks, this could cause issues.
> >
>=20
> Don't full nodes by definition have to have the whole chain? This does ma=
ke
> pruned nodes difficult, but it could also have rules like you can only
> point back so far.

"you can only point back so far" leads to transactions becoming invalid, wh=
ich
is something we've always strictly avoided because it can result in huge
problems during reorgs with transactions being unable to be included in a n=
ew
change. That's exactly why transaction expiry proposals have been shot down
over and over again.

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org

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