From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 0A678959 for ; Wed, 31 May 2017 04:15:39 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from zinan.dashjr.org (zinan.dashjr.org [192.3.11.21]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 67FFD144 for ; Wed, 31 May 2017 04:15:38 +0000 (UTC) Received: from ishibashi.localnet (unknown [IPv6:2001:470:5:265:a45d:823b:2d27:961c]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id 2343138A0093; Wed, 31 May 2017 04:14:28 +0000 (UTC) X-Hashcash: 1:25:170531:bitcoin-dev@lists.linuxfoundation.org::twnobufcbaoHyb0M:a3kBF X-Hashcash: 1:25:170531:jtimon@jtimon.cc::B3ggVQJHPAh0RfB9:KhF1 X-Hashcash: 1:25:170531:macwhyte@gmail.com::JItRFthD9Vy9AgHg:hW3PI From: Luke Dashjr To: bitcoin-dev@lists.linuxfoundation.org, Jorge =?iso-8859-1?q?Tim=F3n?= Date: Wed, 31 May 2017 04:14:25 +0000 User-Agent: KMail/1.13.7 (Linux/4.9.16-gentoo; KDE/4.14.29; x86_64; ; ) References: <201705232023.40588.luke@dashjr.org> In-Reply-To: X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F X-PGP-Key-ID: BD02942421F4889F X-PGP-Keyserver: hkp://pgp.mit.edu MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message-Id: <201705310414.26724.luke@dashjr.org> X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] Hypothetical 2 MB hardfork to follow BIP148 X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 May 2017 04:15:39 -0000 On Wednesday 31 May 2017 1:22:44 AM Jorge Tim=F3n via bitcoin-dev wrote: > Why is it > https://github.com/bitcoin/bitcoin/blob/master/src/validation.cpp#L1661 > not enough at this point? > Why the need for a transaction size limit? Because the bottleneck is hashing the transaction, which costs (in CPU time= )=20 based on its size. Maybe it would make sense to factor sigops into the limi= t,=20 though? On Wednesday 31 May 2017 1:09:26 AM Jean-Paul Kogelman via bitcoin-dev wrot= e: > On May 30, 2017, at 4:50 PM, James MacWhyte wrote: > > Add a transaction-size limit of, say, 10kb and the quadratic hashing > > problem is a non-issue. Donezo. > > That would invalidate any pre-signed transactions that are currently out > there. You can't just change the rules out from under people. Make it 100kB and I think we'd be okay. Those have always been policy- forbidden so there should be no expectation they'd be acceptable in the=20 future. While we're at it, I suggest also specifying a minimum transaction size as= =20 well. The raw minimum possible is 60 bytes, but any sane output would need = at=20 least a hash, so I'd say make the minimum be 8 (60 + 160-bit hash) bytes? Luke