Bitcoin 0.12 release

[achow101]

I've been testing out 0.12.0rc3 in pruned mode, and have run into the following error message when restarting Bitcoin Core: "last wallet synchronisation goes beyond pruned data. You need to -reindex (download the whole blockchain again in case of pruned node)"

To reproduce:
0.) Start from scratch, deleting the entire Bitcoin data directory if it exists (leaving no wallet file or blockchain data).
1.) Install Bitcoin Core
2.) Create Bitcoin data directory if it doesn't exist, create bitcoin.conf, set "prune=550" without quotes
3.) Run Bitcoin Core
4.) After you've verified, say, 100,000 blocks, close Bitcoin Core. Wait until the warning window to not shutdown/restart computer completely closes.
5.) Run Bitcoin Core again, let it verify some more, close it again.
6.) Rinse and repeat step 5...

At some point, I get the above error message on starting Bitcoin Core.

I don't know what exactly is causing this, but if you're like me and you've verified a large amount of blocks and then you're told that you have to start completely over, you'll probably be pissed.

This error message is not new, as a related fix for this kind of error, when converting non-pruned nodes to pruned nodes was made here: https://github.com/bitcoin/bitcoin/issues/6345

While it's obviously easy to reproduce this error *if* you try plopping an *already existing* wallet.dat file into a pruned node data directory and then running Core -- that's not what I've been experiencing. I've been seeing this error with a brand new wallet.dat that was created from scratch *alongside* a fresh, pruned node.

Edit: If it's a brand new node from scratch, it seems that if you delete the wallet.dat after getting this error, a brand new one will be created, and the blockchain will continue to sync from where it left off, so at least there's that, though, it's still a bug.

Not sure what would cause this, but you would get a better response by posting on the github issue tracker. Or rather watch the issue thread that gmaxwell opened for you here: https://github.com/bitcoin/bitcoin/issues/7494

[David Rabahy]

If everyone ran in pruned mode then would that be a problem?  How would a new node catch up from the beginning?  I'm sure it's just that I am missing the obvious point.  Sorry to be such a dummy.

Maybe the idea is at least a few nodes will always keep the full history?  I am willing to if that helps.

[pedrog]

If everyone ran in pruned mode then would that be a problem?  How would a new node catch up from the beginning?  I'm sure it's just that I am missing the obvious point.  Sorry to be such a dummy.

Maybe the idea is at least a few nodes will always keep the full history?  I am willing to if that helps.

Correct, some nodes with the entire blockchain will always need to exist.

[theymos]

If everyone ran in pruned mode then would that be a problem?  How would a new node catch up from the beginning?  I'm sure it's just that I am missing the obvious point.  Sorry to be such a dummy.

Maybe the idea is at least a few nodes will always keep the full history?  I am willing to if that helps.

In the future Core will let you choose to "donate x GB to the network", and then you'll store a random range of historical blocks. Then nodes doing an initial sync will have to search out nodes that have the blocks they want from among these nodes storing chunks of the historical chain. It's a bit like how BitTorrent works.

[wttbs]

I run a full node now on 0.11.2, is it possible to upgrade to 0.12 RCx and still serve the network?

[cr1776]

I run a full node now on 0.11.2, is it possible to upgrade to 0.12 RCx and still serve the network?

Yes, just upgrade it.  Depending on what you mean by "serve the network" you'd want to avoid turning pruning on. 

[David Rabahy]

How many nodes do we need to satisfy initial syncs?  https://bitnodes.21.co/ indicates there are over 5,800 right now.  That seems like plenty for sure.  As pruning becomes more popular, who's job is it make sure the number doesn't dwindle too low?

What would happen if managed to lose every copy of the old blocks?

[Jet Cash]

How many nodes do we need to satisfy initial syncs?  https://bitnodes.21.co/ indicates there are over 5,800 right now.  That seems like plenty for sure.  As pruning becomes more popular, who's job is it make sure the number doesn't dwindle too low?

What would happen if managed to lose every copy of the old blocks?

Keep a copy on a USB stick.

[David Rabahy]

Does it make any sense at all to think about paying folks running full nodes (with or without all old blocks) even if they aren't mining?

[Jet Cash]

Does it make any sense at all to think about paying folks running full nodes (with or without all old blocks) even if they aren't mining?

Paying them might get complicated. It could be worth giving them a partial refund on their own transaction fees though.

[shorena]

Does it make any sense at all to think about paying folks running full nodes (with or without all old blocks) even if they aren't mining?

The question is how you distinguish a real node from a fake one.

[Jet Cash]

Does it make any sense at all to think about paying folks running full nodes (with or without all old blocks) even if they aren't mining?

The question is how you distinguish a real node from a fake one.

Ah! That's beyond my level of knowledge.

[watashi-kokoto]

Ah! That's beyond my level of knowledge.

there's no point having million nodes. 5000 is enough and they would easily handle millions of transactions.

much more important is for people to archive a copy of blockchain and validate it. in this way we can discover every possible problem, scam or attack.

[KiwiParty]

I'm looking forward to this.
The reduced Blockcahin size would help a lot, its 60GB in size already indeed.
The first installation took about two days, as i remember.
This was way too long.

[pedrog]

I'm looking forward to this.
The reduced Blockcahin size would help a lot, its 60GB in size already indeed.
The first installation took about two days, as i remember.
This was way too long.

With pruning mode enable you still need to download and verify the entire blockchain, if you don't wanna do this try a hosted or SPV wallet.

[achow101]

So when we expect this 0.12.0 release to be officially available?

Meanwhile classic gained ground, now they are 14% (830 nodes) of the total number of nodes.

Soon I think. Rc5 was tagged today and during the meeting today it was mentioned that rc5 would be the last rc for 0.12

[Karartma1]

If everyone ran in pruned mode then would that be a problem?  How would a new node catch up from the beginning?  I'm sure it's just that I am missing the obvious point.  Sorry to be such a dummy.

Maybe the idea is at least a few nodes will always keep the full history?  I am willing to if that helps.

In the future Core will let you choose to "donate x GB to the network", and then you'll store a random range of historical blocks. Then nodes doing an initial sync will have to search out nodes that have the blocks they want from among these nodes storing chunks of the historical chain. It's a bit like how BitTorrent works.

This could be the greatest plus thing we need and then I would be more than happy in contributing again.
When you talk about future, how far is this future? thanks 

[gmaxwell]

This could be the greatest plus thing we need and then I would be more than happy in contributing again.
When you talk about future, how far is this future? thanks 

I think it would be done now, if not for all the drama in the last year.

In 0.12 you can run a pruned node and you'll at least relay blocks on the tip.

I hope to see more sophistication maybe towards then end of the year; I'm hesitant to give any concrete numbers in the current climate.

[mmortal03]

So when we expect this 0.12.0 release to be officially available?

Meanwhile classic gained ground, now they are 14% (830 nodes) of the total number of nodes.

RC4 or RC5 will be out soon, some additional bugs were discovered and taken care of.

[mmortal03]

Does it make any sense at all to think about paying folks running full nodes (with or without all old blocks) even if they aren't mining?

So, running a full node is the only way to use Bitcoin in its most trustless form. But there's nothing stopping people from, say, running a full client to achieve this trustlessness, but still turning off the accepting of incoming connections so save bandwidth; well, that is, until *everyone* else decides to do the same, and then there isn't anyone left running an archival node from which to download the blockchain.

Full nodes enforce the consensus rules.  But even miners aren't directly incentivized to run their own full nodes. However, miners and businesses may rely on particular behavior from custom full node features that they may want to make use of, so they will often be incentivized to run their own full nodes for this purpose.