From: Michael Gronager <gronager@ceptacle•com>
To: Mike Hearn <mike@plan99•net>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] Warning: many 0.7 nodes break on large number of tx/block; fork risk
Date: Tue, 12 Mar 2013 13:27:32 +0100 [thread overview]
Message-ID: <D4AD3716-0349-4294-989D-F034A26B295A@ceptacle.com> (raw)
In-Reply-To: <CANEZrP1q4SnP=xEn0FNYQw3t6ZuzuLVF48YMr_hmVuYYmsWyfw@mail.gmail.com>
Well a reversed upgrade is an upgrade that went wrong ;)
Anyway, the incident makes it even more important for people to upgrade, well except, perhaps, for miners...
Forks are caused by rejection criteria, hence:
1. If you introduce new rejection criteria in an upgrade miners should upgrade _first_.
2. If you loosen some rejection criteria miners should upgrade _last_.
3. If you keep the same criteria assume 2.
/M
On 12/03/2013, at 13:11, Mike Hearn <mike@plan99•net> wrote:
> I'm not even sure I'd say the upgrade "went wrong". The problem if
> anything is the upgrade didn't happen fast enough. If we had run out
> of block space a few months from now, or if miners/merchants/exchanges
> had upgraded faster, it'd have made more sense to just roll forward
> and tolerate the loss of the older clients.
>
> This really reinforces the importance of keeping nodes up to date.
>
> On Tue, Mar 12, 2013 at 12:44 PM, Pieter Wuille <pieter.wuille@gmail•com> wrote:
>> On Tue, Mar 12, 2013 at 11:13:09AM +0100, Michael Gronager wrote:
>>> Yes, 0.7 (yes 0.7!) was not sufficiently tested it had an undocumented and unknown criteria for block rejection, hence the upgrade went wrong.
>>
>> We're using "0.7" as a short moniker for all clients, but this was a limitation that all
>> BDB-based bitcoins ever had. The bug is simply a limit in the number of lock objects
>> that was reached.
>>
>> It's ironic that 0.8 was supposed to solve all problems we had due to BDB (except the
>> wallet...), but now it seems it's still coming back to haunt us. I really hated telling
>> miners to go back to 0.7, given all efforts to make 0.8 signficantly more tolerable...
>>
>>> More space in the block is needed indeed, but the real problem you are describing is actually not missing space in the block, but proper handling of mem-pool transactions. They should be pruned on two criteria:
>>>
>>> 1. if they gets to old >24hr
>>> 2. if the client is running out of space, then the oldest should probably be pruned
>>>
>>> clients are anyway keeping, and re-relaying, their own transactions and hence it would mean only little, and only little for clients. Dropping free / old transaction is a much a better behavior than dying... Even a scheme where the client dropped all or random mempool txes would be a tolerable way of handling things (dropping all is similar to a restart, except for no user intervention).
>>
>> Right now, mempools are relatively small in memory usage, but with small block sizes,
>> it indeed risks going up. In 0.8, conflicting (=double spending) transactions in the
>> chain cause clearing the mempool of conflicts, so at least the mempool is bounded by
>> the size of the UTXO subset being spent. Dropping transactions from the memory pool
>> when they run out of space seems a correct solution. I'm less convinced about a
>> deterministic time-based rule, as that creates a double spending incentive at that
>> time, and a counter incentive to spam the network with your risking-to-be-cleared
>> transaction as well.
>>
>> Regarding the block space, we've seen the pct% of one single block chain space consumer
>> grow simultaneously with the introduction of larger blocks, so I'm not actually convinced
>> there is right now a big need for larger blocks (note: right now). The competition for
>> block chain space is mostly an issue for client software which doesn't deal correctly
>> with non-confirming transactions, and misleading users. It's mostly a usability problem
>> now, but increasing block sizes isn't guaranteed to fix that; it may just make more
>> space for spam.
>>
>> However, the presence of this bug, and the fact that a full solution is available (0.8),
>> probably helps achieving consensus fixing it (=a hardfork) is needed, and we should take
>> advantage of that. But please, let's not rush things...
>>
>> --
>> Piter
>
> ------------------------------------------------------------------------------
> Symantec Endpoint Protection 12 positioned as A LEADER in The Forrester
> Wave(TM): Endpoint Security, Q1 2013 and "remains a good choice" in the
> endpoint security space. For insight on selecting the right partner to
> tackle endpoint security challenges, access the full report.
> http://p.sf.net/sfu/symantec-dev2dev
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
next prev parent reply other threads:[~2013-03-12 12:27 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-12 0:18 Pieter Wuille
2013-03-12 1:01 ` Pieter Wuille
2013-03-12 9:10 ` Mike Hearn
2013-03-12 9:53 ` Jorge Timón
2013-03-12 9:57 ` Peter Todd
2013-03-12 10:10 ` Mike Hearn
2013-03-12 10:17 ` Peter Todd
2013-03-12 10:13 ` Michael Gronager
2013-03-12 10:26 ` Peter Todd
2013-03-12 10:43 ` Mike Hearn
2013-03-12 10:40 ` Roy Badami
2013-03-12 11:44 ` Pieter Wuille
2013-03-12 12:11 ` Mike Hearn
2013-03-12 12:27 ` Michael Gronager [this message]
2013-03-12 12:18 ` Jorge Timón
2013-03-12 12:40 ` Jay F
2013-03-12 12:38 ` Gregory Maxwell
2013-03-12 13:00 ` Michael Gronager
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=D4AD3716-0349-4294-989D-F034A26B295A@ceptacle.com \
--to=gronager@ceptacle$(echo .)com \
--cc=bitcoin-development@lists$(echo .)sourceforge.net \
--cc=mike@plan99$(echo .)net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox