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From: =?iso-8859-1?Q?Michael_Gr=F8nager?= <gronager@ceptacle.com>
In-Reply-To: <CAAS2fgRiM9SFGVtYU1GJM8U0z8aMecc3Ng9wM4SNWkE5_MKPwQ@mail.gmail.com>
Date: Wed, 5 Oct 2011 15:44:08 +0200
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Message-Id: <03BEA6AD-7EF2-41D0-91A3-D943A7B2964D@ceptacle.com>
References: <E0AD809E-7446-4E18-9A2D-7E7480F8AB89@ceptacle.com>
	<CAAS2fgRiM9SFGVtYU1GJM8U0z8aMecc3Ng9wM4SNWkE5_MKPwQ@mail.gmail.com>
To: Gregory Maxwell <gmaxwell@gmail.com>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] vtxPrev
Precedence: list

Oups - I was reading the code wrongly - going through =
AddSupportingTransactions carefully again...

The vtxPrev contains a list of the supporting confirmations up to 3 =
confirmations back. So it is only of relevance (and only gets filled) if =
you accept coins that are less than 3 confirmations old. In this case =
you would like to resend the depending transactions to the network in =
case of chain splits.

This makes much more sense, but also, it is only of relevance when you =
accept newly earned coins. And it will only be of relevance for half an =
hour or so.

Cheers,

Michael


On 05/10/2011, at 14:50, Gregory Maxwell wrote:

> On Wed, Oct 5, 2011 at 8:31 AM, Michael Gr=F8nager =
<gronager@ceptacle.com> wrote:
>> The vtxPrev stores 3 transactions back, but as transactions need 7 =
block to maturity and respendability isn't it overkill - I mean it is =
highly unlikely that a transaction gets invalid after 7 confirmations =
and
>=20
> They don't need 7 blocks to maturity and respendability. The software
> will attempt to use older inputs when available but if not it will use
> what it has.  It's also prone to respending its own outputs quickly
> because it reasonably trusts that it won't doublespend its own
> transactions.
>=20
> And, yes, if there is a deep split then its possible that inputs might
> have been spent differently in the new split. But it's not especially
> likely. Retransmitting one of your own txn's parents if its dropped
> but not yet impossible sounds prudent to me.

Michael Gronager, PhD
Owner Ceptacle / NDGF Director, NORDUnet A/S
Jens Juels Gade 33
2100 Copenhagen E
Mobile: +45 31 62 14 01
E-mail: gronager@ceptacle.com