1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
Return-Path: <yanmaani@cock.li>
Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137])
by lists.linuxfoundation.org (Postfix) with ESMTP id 95453C000B
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 20 Apr 2021 01:22:48 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
by smtp4.osuosl.org (Postfix) with ESMTP id 6F6B1402CA
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 20 Apr 2021 01:22:48 +0000 (UTC)
X-Virus-Scanned: amavisd-new at osuosl.org
X-Spam-Flag: NO
X-Spam-Score: 0.59
X-Spam-Level:
X-Spam-Status: No, score=0.59 tagged_above=-999 required=5
tests=[BAYES_40=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1,
DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RDNS_NONE=0.793,
SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=no autolearn_force=no
Authentication-Results: smtp4.osuosl.org (amavisd-new);
dkim=pass (2048-bit key) header.d=cock.li
Received: from smtp4.osuosl.org ([127.0.0.1])
by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id b69ILQZeRBKU
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 20 Apr 2021 01:22:44 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.8.0
Received: from mail.cock.li (unknown [37.120.193.123])
by smtp4.osuosl.org (Postfix) with ESMTPS id D88BC40254
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 20 Apr 2021 01:22:43 +0000 (UTC)
MIME-Version: 1.0
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cock.li; s=mail;
t=1618881754; bh=F8mbpoWsrg69xtGpeRNG/DWGHIv5yR13Iqvq5SuJVUY=;
h=Date:From:To:Subject:From;
b=re60BnbRC6KlAhgzgv0j8jP+oqGShQsgdYtuSZlmgTOS7lXYPTpb3HPn2IbrFzxVD
ChElh+ZKs+XTvZmt/otIpN8IkEsSyoHJiwX/T4U/XcnHwOoc36RmQ3Q01v11ScqU+P
UfgCpdzNLm1LjrzJhMKXQZ+jBPkTQ3wusvn+oT3+4LQiy/xfsXvQaeFx5Fp7rHoywk
0ea+tq4/t2SuJXA1ioIQ8y9TNPhkDj1IsDSq2pk/HTBGU66W2RfwR+rP3xDSNHDeRf
pUC5XfTLx5OEEpb2QNVdaItDWCUuclZI1UQXzlDaK+5LnJZ5zZClRE7ZjgqEz7tK3M
DbGwEWXABS6PA==
Content-Type: text/plain; charset=US-ASCII;
format=flowed
Content-Transfer-Encoding: 7bit
Date: Tue, 20 Apr 2021 01:22:34 +0000
From: yanmaani@cock.li
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Message-ID: <42775695100e48eb5884d38e60b70957@cock.li>
X-Sender: yanmaani@cock.li
User-Agent: Roundcube Webmail/1.3.15
X-Mailman-Approved-At: Tue, 20 Apr 2021 02:28:26 +0000
Subject: [bitcoin-dev] Block weight penalty for UTXO set growth
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Tue, 20 Apr 2021 01:22:48 -0000
Bitcoin presently suffers from unconstrained UTXO set growth. It would
be possible to disincentivize this and incentivize consolidating UTXOs
by adding a block weight penalty for UTXO creation, and bonus for UTXO
destruction:
* For each block, calculate the net change in UTXOs. If all the
transactions in a block consume 6,256 inputs and create 6,512 outputs,
the net change is +256.
* For each block, change the weight limit by -penalty * delta
* For example, if the penalty is 10 vB/UTXO, that block would be 10*256
= 2560 vB smaller. At a fee of 150 sat/vB, this would reduce the
potential transaction fees by 0.00384000 BTC ($230 at current prices)
(Alternatively, it would also be possible to make the penalty in coin,
which would require miners to fail to claim/burn an equivalent amount of
subsidy.)
A problem is that it is not possible to increase the weight limit (or
the block reward). I can see three possible solutions to this:
1) Let any excess be wasted. Miners can only use consolidated UTXOs to
offset new ones.
2) Decrease the weight limit slightly (i.e. by 1%), so that miners have
an incentive to consolidate UTXOs at least up to that limit.
3) Increase the weight limit, but only if miners consolidate enough
UTXOs.
Aside from the obvious issues with the third option (it would be a
hardfork), another problem is that this would make it harder for low-fee
transactions to get confirmed; on blocks with bad fees, miners might
instead opt to create a load of dust UTXOs, so they can destroy them on
blocks with very high fees to free up capacity. On the other hand, this
might be seen as a feature rather than a bug, since it would allow block
sizes to vary by demand, a bit like VBR vs. CBR in audio compression.
Thoughts? Has this been discussed before?
|
